christopher/rosetta-code · Datasets at Hugging Face

task_url stringlengths 30 116	task_name stringlengths 2 86	task_description stringlengths 0 14.4k	language_url stringlengths 2 53	language_name stringlengths 1 52	code stringlengths 0 61.9k
http://rosettacode.org/wiki/Rot-13	Rot-13	Task Implement a rot-13 function (or procedure, class, subroutine, or other "callable" object as appropriate to your programming environment). Optionally wrap this function in a utility program (like tr, which acts like a common UNIX utility, performing a line-by-line rot-13 encoding of every line of input contained in each file listed on its command line, or (if no filenames are passed thereon) acting as a filter on its "standard input." (A number of UNIX scripting languages and utilities, such as awk and sed either default to processing files in this way or have command line switches or modules to easily implement these wrapper semantics, e.g., Perl and Python). The rot-13 encoding is commonly known from the early days of Usenet "Netnews" as a way of obfuscating text to prevent casual reading of spoiler or potentially offensive material. Many news reader and mail user agent programs have built-in rot-13 encoder/decoders or have the ability to feed a message through any external utility script for performing this (or other) actions. The definition of the rot-13 function is to simply replace every letter of the ASCII alphabet with the letter which is "rotated" 13 characters "around" the 26 letter alphabet from its normal cardinal position (wrapping around from z to a as necessary). Thus the letters abc become nop and so on. Technically rot-13 is a "mono-alphabetic substitution cipher" with a trivial "key". A proper implementation should work on upper and lower case letters, preserve case, and pass all non-alphabetic characters in the input stream through without alteration. Related tasks Caesar cipher Substitution Cipher Vigenère Cipher/Cryptanalysis Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#Perl	Perl	sub rot13 { shift =~ tr/A-Za-z/N-ZA-Mn-za-m/r; } print rot13($_) while (<>);
http://rosettacode.org/wiki/Roman_numerals/Encode	Roman numerals/Encode	Task Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero. In Roman numerals: 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC 2008 is written as 2000=MM, 8=VIII; or MMVIII 1666 uses each Roman symbol in descending order: MDCLXVI	#Oforth	Oforth	[ [1000,"M"], [900,"CM"], [500,"D"], [400,"CD"], [100,"C"], [90,"XC"], [50,"L"], [40,"XL"], [10,"X"], [9,"IX"], [5,"V"], [4,"IV"], [1,"I"] ] const: Romans : roman(n) \| r \| StringBuffer new Romans forEach: r [ while(r first n <=) [ r second << n r first - ->n ] ] ;
http://rosettacode.org/wiki/Roman_numerals/Decode	Roman numerals/Decode	Task Create a function that takes a Roman numeral as its argument and returns its value as a numeric decimal integer. You don't need to validate the form of the Roman numeral. Modern Roman numerals are written by expressing each decimal digit of the number to be encoded separately, starting with the leftmost decimal digit and skipping any 0s (zeroes). 1990 is rendered as MCMXC (1000 = M, 900 = CM, 90 = XC) and 2008 is rendered as MMVIII (2000 = MM, 8 = VIII). The Roman numeral for 1666, MDCLXVI, uses each letter in descending order.	#PureBasic	PureBasic	Procedure romanDec(roman.s) Protected i, n, lastval, arabic For i = Len(roman) To 1 Step -1 Select UCase(Mid(roman, i, 1)) Case "M" n = 1000 Case "D" n = 500 Case "C" n = 100 Case "L" n = 50 Case "X" n = 10 Case "V" n = 5 Case "I" n = 1 Default n = 0 EndSelect If (n < lastval) arabic - n Else arabic + n EndIf lastval = n Next ProcedureReturn arabic EndProcedure If OpenConsole() PrintN(Str(romanDec("MCMXCIX"))) ;1999 PrintN(Str(romanDec("MDCLXVI"))) ;1666 PrintN(Str(romanDec("XXV"))) ;25 PrintN(Str(romanDec("CMLIV"))) ;954 PrintN(Str(romanDec("MMXI"))) ;2011 Print(#CRLF$ + #CRLF$ + "Press ENTER to exit"): Input() CloseConsole() EndIf
http://rosettacode.org/wiki/Run-length_encoding	Run-length encoding	Run-length encoding You are encouraged to solve this task according to the task description, using any language you may know. Task Given a string containing uppercase characters (A-Z), compress repeated 'runs' of the same character by storing the length of that run, and provide a function to reverse the compression. The output can be anything, as long as you can recreate the input with it. Example Input: WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW Output: 12W1B12W3B24W1B14W Note: the encoding step in the above example is the same as a step of the Look-and-say sequence.	#VBA	VBA	Option Explicit Sub Main() Dim p As String p = length_encoding("WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW") Debug.Print p Debug.Print length_decoding(p) End Sub Private Function length_encoding(S As String) As String Dim F As String, r As String, a As String, n As Long, c As Long, k As Long r = Left(S, 1) c = 1 For n = 2 To Len(S) If r <> Mid(S, n, 1) Then a = a & c & r r = Mid(S, n, 1) c = 1 Else c = c + 1 End If Next length_encoding = a & c & r End Function Private Function length_decoding(S As String) As String Dim F As Long, r As String, a As String For F = 1 To Len(S) If IsNumeric(Mid(S, F, 1)) Then r = r & Mid(S, F, 1) Else a = a & String(CLng(r), Mid(S, F, 1)) r = vbNullString End If Next length_decoding = a End Function
http://rosettacode.org/wiki/Repeat_a_string	Repeat a string	Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("", 5) => "****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#AppleScript	AppleScript	set str to "ha" set final_string to "" repeat 5 times set final_string to final_string & str end repeat
http://rosettacode.org/wiki/Return_multiple_values	Return multiple values	Task Show how to return more than one value from a function.	#Clojure	Clojure	(defn quot-rem [m n] [(quot m n) (rem m n)]) ; The following prints 3 2. (let [[q r] (quot-rem 11 3)] (println q) (println r))
http://rosettacode.org/wiki/Rep-string	Rep-string	Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#Ada	Ada	with Ada.Command_Line, Ada.Text_IO, Ada.Strings.Fixed; procedure Rep_String is function Find_Largest_Rep_String(S:String) return String is L: Natural := S'Length; begin for I in reverse 1 .. L/2 loop declare use Ada.Strings.Fixed; T: String := S(S'First .. S'First + I-1); -- the first I characters of S U: String := (1+(L/I)) * T; -- repeat T so often that U'Length >= L begin -- compare first L characers of U with S if U(U'First .. U'First + S'Length -1) = S then return T; -- T is a rep-string end if; end; end loop; return ""; -- no rep string; end Find_Largest_Rep_String; X: String := Ada.Command_Line.Argument(1); Y: String := Find_Largest_Rep_String(X); begin if Y="" then Ada.Text_IO.Put_Line("No rep-string for """ & X & """"); else Ada.Text_IO.Put_Line("Longest rep-string for """& X &""": """& Y &""""); end if; end Rep_String;
http://rosettacode.org/wiki/Regular_expressions	Regular expressions	Task match a string against a regular expression substitute part of a string using a regular expression	#Ada	Ada	with Ada.Text_IO; with Gnat.Regpat; use Ada.Text_IO; procedure Regex is package Pat renames Gnat.Regpat; procedure Search_For_Pattern(Compiled_Expression: Pat.Pattern_Matcher; Search_In: String; First, Last: out Positive; Found: out Boolean) is Result: Pat.Match_Array (0 .. 1); begin Pat.Match(Compiled_Expression, Search_In, Result); Found := not Pat."="(Result(1), Pat.No_Match); if Found then First := Result(1).First; Last := Result(1).Last; end if; end Search_For_Pattern; Word_Pattern: constant String := "([a-zA-Z]+)"; Str: String:= "I love PATTERN matching!"; Current_First: Positive := Str'First; First, Last: Positive; Found: Boolean; begin -- first, find all the words in Str loop Search_For_Pattern(Pat.Compile(Word_Pattern), Str(Current_First .. Str'Last), First, Last, Found); exit when not Found; Put_Line("<" & Str(First .. Last) & ">"); Current_First := Last+1; end loop; -- second, replace "PATTERN" in Str by "pattern" Search_For_Pattern(Pat.Compile("(PATTERN)"), Str, First, Last, Found); Str := Str(Str'First .. First-1) & "pattern" & Str(Last+1 .. Str'Last); Put_Line(Str); end Regex;
http://rosettacode.org/wiki/Reverse_a_string	Reverse a string	Task Take a string and reverse it. For example, "asdf" becomes "fdsa". Extra credit Preserve Unicode combining characters. For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa". Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#8th	8th	"abc" s:rev
http://rosettacode.org/wiki/Rendezvous	Rendezvous	Demonstrate the “rendezvous” communications technique by implementing a printer monitor.	#Erlang	Erlang	-module( rendezvous ). -export( [task/0] ). task() -> Printer_pid = erlang:spawn( fun() -> printer(1, 5) end ), Reserve_printer_pid = erlang:spawn( fun() -> printer(2, 5) end ), Monitor_pid = erlang:spawn( fun() -> printer_monitor(Printer_pid, Reserve_printer_pid) end ), erlang:spawn( fun() -> print(Monitor_pid, humpty_dumpty()) end ), erlang:spawn( fun() -> print(Monitor_pid, mother_goose()) end ). humpty_dumpty() -> ["Humpty Dumpty sat on a wall.", "Humpty Dumpty had a great fall.", "All the king's horses and all the king's men,", "Couldn't put Humpty together again."]. mother_goose() -> ["Old Mother Goose,", "When she wanted to wander,", "Would ride through the air,", "On a very fine gander.", "Jack's mother came in,", "And caught the goose soon,", "And mounting its back,", "Flew up to the moon."]. print( Pid, Lines ) -> io:fwrite( "Print ~p started~n", [erlang:self()] ), print( Pid, Lines, infinity ). print( _Pid, [], _Timeout ) -> ok; print( Pid, [Line \| T], Timeout ) -> print_line( Pid, Line, Timeout ), print_line_done(), print( Pid, T, Timeout ). print_line( Pid, Line, Timeout ) -> Pid ! {print, Line, erlang:self()}, receive {print, started} -> ok after Timeout -> erlang:throw( timeout ) end. print_line_done() -> receive {printer, ok} -> ok; {printer, out_of_ink} -> erlang:throw( out_of_ink ) end. printer( N, 0 ) -> receive {print, _Line, Pid} -> Pid ! {printer, out_of_ink} end, printer( N, 0 ); printer( N, Ink ) -> receive {print, Line, Pid} -> Pid ! {printer, ok}, io:fwrite( "~p: ", [N] ), [io:fwrite("~c", [X]) \|\| X <- Line], io:nl() end, printer( N, Ink - 1 ). printer_monitor( Printer, Reserve ) -> {Line, Pid} = printer_monitor_get_line(), Result = printer_monitor_print_line( Printer, Line ), printer_monitor_reserve( Result, Reserve, Line, Pid ), printer_monitor( Printer, Reserve ). printer_monitor_get_line() -> receive {print, Line, Pid} -> Pid ! {print, started}, {Line, Pid} end. printer_monitor_print_line( Printer_pid, Line ) -> Printer_pid ! {print, Line, erlang:self()}, receive {printer, Result} -> Result end. printer_monitor_reserve( ok, _Reserve_pid, _Line, Pid ) -> Pid ! {printer, ok}; printer_monitor_reserve( out_of_ink, Reserve_pid, Line, Pid ) -> Reserve_pid ! {print, Line, Pid}.
http://rosettacode.org/wiki/Repeat	Repeat	Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.	#AutoHotkey	AutoHotkey	repeat("fMsgBox",3) return repeat(f, n){ loop % n %f%() } fMsgBox(){ MsgBox hello }
http://rosettacode.org/wiki/Rename_a_file	Rename a file	Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)	#AutoHotkey	AutoHotkey	FileMove, oldname, newname
http://rosettacode.org/wiki/Rename_a_file	Rename a file	Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)	#AutoIt	AutoIt	$ awk 'BEGIN{system("mv input.txt output.txt")}' $ awk 'BEGIN{system("mv docs mydocs")}' $ awk 'BEGIN{system("mv /input.txt /output.txt")}' $ awk 'BEGIN{system("mv docs mydocs")}'
http://rosettacode.org/wiki/RIPEMD-160	RIPEMD-160	RIPEMD-160 is another hash function; it computes a 160-bit message digest. There is a RIPEMD-160 home page, with test vectors and pseudocode for RIPEMD-160. For padding the message, RIPEMD-160 acts like MD4 (RFC 1320). Find the RIPEMD-160 message digest of a string of octets. Use the ASCII encoded string “Rosetta Code”. You may either call an RIPEMD-160 library, or implement RIPEMD-160 in your language.	#Tcl	Tcl	package require ripemd160 puts [ripemd::ripemd160 -hex "Rosetta Code"]
http://rosettacode.org/wiki/RIPEMD-160	RIPEMD-160	RIPEMD-160 is another hash function; it computes a 160-bit message digest. There is a RIPEMD-160 home page, with test vectors and pseudocode for RIPEMD-160. For padding the message, RIPEMD-160 acts like MD4 (RFC 1320). Find the RIPEMD-160 message digest of a string of octets. Use the ASCII encoded string “Rosetta Code”. You may either call an RIPEMD-160 library, or implement RIPEMD-160 in your language.	#Wren	Wren	import "/crypto" for Ripemd160 import "/fmt" for Fmt var strings = [ "", "a", "abc", "message digest", "abcdefghijklmnopqrstuvwxyz", "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789", "12345678901234567890123456789012345678901234567890123456789012345678901234567890", "The quick brown fox jumps over the lazy dog", "The quick brown fox jumps over the lazy cog", "Rosetta Code" ] for (s in strings) { var hash = Ripemd160.digest(s) Fmt.print("$s <== '$0s'", hash, s) }
http://rosettacode.org/wiki/Resistor_mesh	Resistor mesh	Task Given 10×10 grid nodes (as shown in the image) interconnected by 1Ω resistors as shown, find the resistance between points A and B. See also (humor, nerd sniping) xkcd.com cartoon	#Modula-2	Modula-2	MODULE ResistorMesh; FROM RConversions IMPORT RealToStringFixed; FROM Terminal IMPORT WriteString,WriteLn,ReadChar; CONST S = 10; TYPE Node = RECORD v : LONGREAL; fixed : INTEGER; END; PROCEDURE SetBoundary(VAR m : ARRAY OF ARRAY OF Node); BEGIN m[1][1].v := 1.0; m[1][1].fixed := 1; m[6][7].v := -1.0; m[6][7].fixed := -1; END SetBoundary; PROCEDURE CalcDiff(VAR m,d : ARRAY OF ARRAY OF Node) : LONGREAL; VAR total,v : LONGREAL; i,j,n : INTEGER; BEGIN total := 0.0; FOR i:=0 TO S DO FOR j:=0 TO S DO v := 0.0; n := 0; IF i>0 THEN v := v + m[i-1][j].v; INC(n); END; IF j>0 THEN v := v + m[i][j-1].v; INC(n); END; IF i+1<S THEN v := v + m[i+1][j].v; INC(n); END; IF j+1<S THEN v := v + m[i][j+1].v; INC(n); END; v := m[i][j].v - v / LFLOAT(n); d[i][j].v := v; IF m[i][j].fixed=0 THEN total := total + vv; END; END; END; RETURN total; END CalcDiff; PROCEDURE Iter(m : ARRAY OF ARRAY OF Node) : LONGREAL; VAR d : ARRAY[0..S] OF ARRAY[0..S] OF Node; i,j,k : INTEGER; cur : ARRAY[0..2] OF LONGREAL; diff : LONGREAL; BEGIN FOR i:=0 TO S DO FOR j:=0 TO S DO d[i][j] := Node{0.0,0}; END; END; diff := 1.0E10; WHILE diff>1.0E-24 DO SetBoundary(m); diff := CalcDiff(m,d); FOR i:=0 TO S DO FOR j:=0 TO S DO m[i][j].v := m[i][j].v - d[i][j].v; END; END; END; FOR i:=0 TO S DO FOR j:=0 TO S DO k:=0; IF i#0 THEN INC(k) END; IF j#0 THEN INC(k) END; IF i<S-1 THEN INC(k) END; IF j<S-1 THEN INC(k) END; cur[m[i][j].fixed+1] := cur[m[i][j].fixed+1] + d[i][j].vLFLOAT(k); END; END; RETURN (cur[2]-cur[0]) / 2.0; END Iter; VAR mesh : ARRAY[0..S] OF ARRAY[0..S] OF Node; buf : ARRAY[0..32] OF CHAR; r : LONGREAL; pos : CARDINAL; ok : BOOLEAN; BEGIN pos := 0; r := 2.0 / Iter(mesh); WriteString("R = "); RealToStringFixed(r, 15,0, buf, pos, ok); WriteString(buf); WriteString(" ohms"); WriteLn; ReadChar; END ResistorMesh.
http://rosettacode.org/wiki/Respond_to_an_unknown_method_call	Respond to an unknown method call	Task Demonstrate how to make the object respond (sensibly/usefully) to an invocation of a method on it that it does not support through its class definitions. Note that this is not the same as just invoking a defined method whose name is given dynamically; the method named at the point of invocation must not be defined. This task is intended only for object systems that use a dynamic dispatch mechanism without static checking. Related task Send an unknown method call.	#Scala	Scala	class DynamicTest extends Dynamic { def foo()=println("this is foo") def bar()=println("this is bar") def applyDynamic(name: String)(args: Any*)={ println("tried to handle unknown method "+name) if(!args.isEmpty) println(" it had arguments: "+args.mkString(",")) } } object DynamicTest { def main(args: Array[String]): Unit = { val d=new DynamicTest() d.foo() d.bar() d.grill() d.ding("dong") } }
http://rosettacode.org/wiki/Respond_to_an_unknown_method_call	Respond to an unknown method call	Task Demonstrate how to make the object respond (sensibly/usefully) to an invocation of a method on it that it does not support through its class definitions. Note that this is not the same as just invoking a defined method whose name is given dynamically; the method named at the point of invocation must not be defined. This task is intended only for object systems that use a dynamic dispatch mechanism without static checking. Related task Send an unknown method call.	#Sidef	Sidef	class Example { method foo { say "this is foo" } method bar { say "this is bar" } method AUTOLOAD(_, name, *args) { say ("tried to handle unknown method %s" % name); if (args.len > 0) { say ("it had arguments: %s" % args.join(', ')); } } } var example = Example.new; example.foo; # prints “this is foo” example.bar; # prints “this is bar” example.grill; # prints “tried to handle unknown method grill” example.ding("dong"); # prints “tried to handle unknown method ding” # prints “it had arguments: dong”
http://rosettacode.org/wiki/Reverse_words_in_a_string	Reverse words in a string	Task Reverse the order of all tokens in each of a number of strings and display the result; the order of characters within a token should not be modified. Example Hey you, Bub! would be shown reversed as: Bub! you, Hey Tokens are any non-space characters separated by spaces (formally, white-space); the visible punctuation form part of the word within which it is located and should not be modified. You may assume that there are no significant non-visible characters in the input. Multiple or superfluous spaces may be compressed into a single space. Some strings have no tokens, so an empty string (or one just containing spaces) would be the result. Display the strings in order (1st, 2nd, 3rd, ···), and one string per line. (You can consider the ten strings as ten lines, and the tokens as words.) Input data (ten lines within the box) line ╔════════════════════════════════════════╗ 1 ║ ---------- Ice and Fire ------------ ║ 2 ║ ║ ◄─── a blank line here. 3 ║ fire, in end will world the say Some ║ 4 ║ ice. in say Some ║ 5 ║ desire of tasted I've what From ║ 6 ║ fire. favor who those with hold I ║ 7 ║ ║ ◄─── a blank line here. 8 ║ ... elided paragraph last ... ║ 9 ║ ║ ◄─── a blank line here. 10 ║ Frost Robert ----------------------- ║ ╚════════════════════════════════════════╝ Cf. Phrase reversals	#COBOL	COBOL	program-id. rev-word. data division. working-storage section. 1 text-block. 2 pic x(36) value "---------- Ice and Fire ------------". 2 pic x(36) value " ". 2 pic x(36) value "fire, in end will world the say Some". 2 pic x(36) value "ice. in say Some ". 2 pic x(36) value "desire of tasted I've what From ". 2 pic x(36) value "fire. favor who those with hold I ". 2 pic x(36) value " ". 2 pic x(36) value "... elided paragraph last ... ". 2 pic x(36) value " ". 2 pic x(36) value "Frost Robert -----------------------". 1 redefines text-block. 2 occurs 10. 3 text-line pic x(36). 1 text-word. 2 wk-len binary pic 9(4). 2 wk-word pic x(36). 1 word-stack. 2 occurs 10. 3 word-entry. 4 word-len binary pic 9(4). 4 word pic x(36). 1 binary. 2 i pic 9(4). 2 pos pic 9(4). 2 word-stack-ptr pic 9(4). procedure division. perform varying i from 1 by 1 until i > 10 perform push-words perform pop-words end-perform stop run . push-words. move 1 to pos move 0 to word-stack-ptr perform until pos > 36 unstring text-line (i) delimited by all space into wk-word count in wk-len pointer pos end-unstring add 1 to word-stack-ptr move text-word to word-entry (word-stack-ptr) end-perform . pop-words. perform varying word-stack-ptr from word-stack-ptr by -1 until word-stack-ptr < 1 move word-entry (word-stack-ptr) to text-word display wk-word (1:wk-len) space with no advancing end-perform display space . end program rev-word.
http://rosettacode.org/wiki/Rot-13	Rot-13	Task Implement a rot-13 function (or procedure, class, subroutine, or other "callable" object as appropriate to your programming environment). Optionally wrap this function in a utility program (like tr, which acts like a common UNIX utility, performing a line-by-line rot-13 encoding of every line of input contained in each file listed on its command line, or (if no filenames are passed thereon) acting as a filter on its "standard input." (A number of UNIX scripting languages and utilities, such as awk and sed either default to processing files in this way or have command line switches or modules to easily implement these wrapper semantics, e.g., Perl and Python). The rot-13 encoding is commonly known from the early days of Usenet "Netnews" as a way of obfuscating text to prevent casual reading of spoiler or potentially offensive material. Many news reader and mail user agent programs have built-in rot-13 encoder/decoders or have the ability to feed a message through any external utility script for performing this (or other) actions. The definition of the rot-13 function is to simply replace every letter of the ASCII alphabet with the letter which is "rotated" 13 characters "around" the 26 letter alphabet from its normal cardinal position (wrapping around from z to a as necessary). Thus the letters abc become nop and so on. Technically rot-13 is a "mono-alphabetic substitution cipher" with a trivial "key". A proper implementation should work on upper and lower case letters, preserve case, and pass all non-alphabetic characters in the input stream through without alteration. Related tasks Caesar cipher Substitution Cipher Vigenère Cipher/Cryptanalysis Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#Phix	Phix	function rot13(string s) integer ch for i=1 to length(s) do ch = upper(s[i]) if ch>='A' and ch<='Z' then s[i] += iff(ch<='M',+13,-13) end if end for return s end function ?rot13("abjurer NOWHERE.")
http://rosettacode.org/wiki/Roman_numerals/Encode	Roman numerals/Encode	Task Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero. In Roman numerals: 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC 2008 is written as 2000=MM, 8=VIII; or MMVIII 1666 uses each Roman symbol in descending order: MDCLXVI	#OpenEdge.2FProgress	OpenEdge/Progress	FUNCTION encodeRoman RETURNS CHAR ( i_i AS INT ): DEF VAR cresult AS CHAR. DEF VAR croman AS CHAR EXTENT 7 INIT [ "M", "D", "C", "L", "X", "V", "I" ]. DEF VAR idecimal AS INT EXTENT 7 INIT [ 1000, 500, 100, 50, 10, 5, 1 ]. DEF VAR ipos AS INT INIT 1. DO WHILE i_i > 0: IF i_i - idecimal[ ipos ] >= 0 THEN ASSIGN cresult = cresult + croman[ ipos ] i_i = i_i - idecimal[ ipos ] . ELSE IF ipos < EXTENT( croman ) - 1 AND i_i - ( idecimal[ ipos ] - idecimal[ ipos + 2 ] ) >= 0 THEN ASSIGN cresult = cresult + croman[ ipos + 2 ] + croman[ ipos ] i_i = i_i - ( idecimal[ ipos ] - idecimal[ ipos + 2 ] ) ipos = ipos + 1 . ELSE ipos = ipos + 1. END. RETURN cresult. END FUNCTION. /* encodeRoman */ MESSAGE 1990 encodeRoman( 1990 ) SKIP 2008 encodeRoman( 2008 ) SKIP 2000 encodeRoman( 2000 ) SKIP 1666 encodeRoman( 1666 ) SKIP VIEW-AS ALERT-BOX.
http://rosettacode.org/wiki/Roman_numerals/Decode	Roman numerals/Decode	Task Create a function that takes a Roman numeral as its argument and returns its value as a numeric decimal integer. You don't need to validate the form of the Roman numeral. Modern Roman numerals are written by expressing each decimal digit of the number to be encoded separately, starting with the leftmost decimal digit and skipping any 0s (zeroes). 1990 is rendered as MCMXC (1000 = M, 900 = CM, 90 = XC) and 2008 is rendered as MMVIII (2000 = MM, 8 = VIII). The Roman numeral for 1666, MDCLXVI, uses each letter in descending order.	#Python	Python	_rdecode = dict(zip('MDCLXVI', (1000, 500, 100, 50, 10, 5, 1))) def decode( roman ): result = 0 for r, r1 in zip(roman, roman[1:]): rd, rd1 = _rdecode[r], _rdecode[r1] result += -rd if rd < rd1 else rd return result + _rdecode[roman[-1]] if __name__ == '__main__': for r in 'MCMXC MMVIII MDCLXVI'.split(): print( r, decode(r) )
http://rosettacode.org/wiki/Run-length_encoding	Run-length encoding	Run-length encoding You are encouraged to solve this task according to the task description, using any language you may know. Task Given a string containing uppercase characters (A-Z), compress repeated 'runs' of the same character by storing the length of that run, and provide a function to reverse the compression. The output can be anything, as long as you can recreate the input with it. Example Input: WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW Output: 12W1B12W3B24W1B14W Note: the encoding step in the above example is the same as a step of the Look-and-say sequence.	#Vedit_macro_language	Vedit macro language	:RL_ENCODE: BOF While (!At_EOF) { if (At_EOL) { Line(1) Continue } // skip newlines #1 = Cur_Char // #1 = character Match("(.)\1*", REGEXP) // count run length #2 = Chars_Matched // #2 = run length if (#2 > 127) { #2 = 127 } // can be max 127 if (#2 > 1 \|\| #1 > 127) { Del_Char(#2) Ins_Char(#2 \| 128) // run length (high bit set) Ins_Char(#1) // character } else { // single ASCII char Char // skip } } Return :RL_DECODE: BOF While (!At_EOF) { #2 = Cur_Char if (#2 > 127) { // is this run length? #1 = Cur_Char(1) // #1 = character value Del_Char(2) Ins_Char(#1, COUNT, #2 & 127) } else { // single ASCII char Char } } Return
http://rosettacode.org/wiki/Repeat_a_string	Repeat a string	Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("", 5) => "****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#Applesoft_BASIC	Applesoft BASIC	FOR I = 1 TO 5 : S$ = S$ + "HA" : NEXT ? "X" SPC(20) "X"
http://rosettacode.org/wiki/Repeat_a_string	Repeat a string	Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("", 5) => "****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#Arturo	Arturo	print repeat "ha" 5
http://rosettacode.org/wiki/Return_multiple_values	Return multiple values	Task Show how to return more than one value from a function.	#CLU	CLU	% Returning multiple values (along with type parameterization) % was actually invented with CLU. % Do note that the procedure is actually returning multiple % values; it's not returning a tuple and unpacking it. % That doesn't exist in CLU. % For added CLU-ness, this function is fully general, requiring % only that its arguments support addition and subtraction in any way add_sub = proc [T,U,V,W: type] (a: T, b: U) returns (V, W) signals (overflow) where T has add: proctype (T,U) returns (V) signals (overflow), sub: proctype (T,U) returns (W) signals (overflow) return (a+b, a-b) resignal overflow end add_sub % And actually using it start_up = proc () add_sub_int = add_sub[int,int,int,int] % boring, but does what you'd expect po: stream := stream$primary_output() % returning two values from the function sum, diff: int := add_sub_int(33, 12) % print out both stream$putl(po, "33 + 12 = " \|\| int$unparse(sum)) stream$putl(po, "33 - 12 = " \|\| int$unparse(diff)) end start_up
http://rosettacode.org/wiki/Return_multiple_values	Return multiple values	Task Show how to return more than one value from a function.	#CMake	CMake	# Returns the first and last characters of string. function(firstlast string first last) # f = first character. string(SUBSTRING "${string}" 0 1 f) # g = last character. string(LENGTH "${string}" length) math(EXPR index "${length} - 1") string(SUBSTRING "${string}" ${index} 1 g) # Return both characters. set("${first}" "${f}" PARENT_SCOPE) set("${last}" "${g}" PARENT_SCOPE) endfunction(firstlast) firstlast("Rosetta Code" begin end) message(STATUS "begins with ${begin}, ends with ${end}")
http://rosettacode.org/wiki/Rep-string	Rep-string	Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#ALGOL_68	ALGOL 68	# procedure to find the longest rep-string in a given string # # the input string is not validated to contain only "0" and "1" characters # PROC longest rep string = ( STRING input )STRING: BEGIN STRING result := ""; # ensure the string we are working on has a lower-bound of 1 # STRING str = input[ AT 1 ]; # work backwards from half the input string looking for a rep-string # FOR string length FROM UPB str OVER 2 BY -1 TO 1 WHILE STRING left substring = str[ 1 : string length ]; # if the left substgring repeated a sufficient number of times # # (truncated on the right) is equal to the original string, then # # we have found the longest rep-string # STRING repeated string = ( left substring * ( ( UPB str OVER string length ) + 1 ) )[ 1 : UPB str ]; IF str = repeated string THEN # found a rep-string # result := left substring; FALSE ELSE # not a rep-string, keep looking # TRUE FI DO SKIP OD; result END; # longest rep string # # test the longest rep string procedure # main: ( []STRING tests = ( "1001110011" , "1110111011" , "0010010010" , "1010101010" , "1111111111" , "0100101101" , "0100100" , "101" , "11" , "00" , "1" ); FOR test number FROM LWB tests TO UPB tests DO STRING rep string = longest rep string( tests[ test number ] ); print( ( tests[ test number ] , ": " , IF rep string = "" THEN "no rep string" ELSE "longest rep string: """ + rep string + """" FI , newline ) ) OD )
http://rosettacode.org/wiki/Regular_expressions	Regular expressions	Task match a string against a regular expression substitute part of a string using a regular expression	#ALGOL_68	ALGOL 68	INT match=0, no match=1, out of memory error=2, other error=3; STRING str := "i am a string"; # Match: # STRING m := "string$"; INT start, end; IF grep in string(m, str, start, end) = match THEN printf(($"Ends with """g""""l$, str[start:end])) FI; # Replace: # IF sub in string(" a ", " another ",str) = match THEN printf(($gl$, str)) FI;
http://rosettacode.org/wiki/Reverse_a_string	Reverse a string	Task Take a string and reverse it. For example, "asdf" becomes "fdsa". Extra credit Preserve Unicode combining characters. For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa". Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#ACL2	ACL2	(reverse "hello")
http://rosettacode.org/wiki/Rendezvous	Rendezvous	Demonstrate the “rendezvous” communications technique by implementing a printer monitor.	#F.23	F#	open System type PrinterCommand = Print of string // a message is a command and a facility to return an exception type Message = Message of PrinterCommand * AsyncReplyChannel<Exception option> // thrown if we have no more ink (and neither has our possible backup printer) exception OutOfInk type Printer(id, ?backup:Printer) = let mutable ink = 5 // the actual printing logic as a private function let print line = if ink > 0 then printf "%d: " id Seq.iter (printf "%c") line printf "\n" ink <- ink - 1 else match backup with \| Some p -> p.Print line \| None -> raise OutOfInk // use a MailboxProcessor to process commands asynchronously; // if an exception occurs, we return it to the calling thread let agent = MailboxProcessor.Start( fun inbox -> async { while true do let! Message (command, replyChannel) = inbox.Receive() try match command with \| Print line -> print line replyChannel.Reply None with \| ex -> replyChannel.Reply (Some ex) }) // public printing method: // send Print command and propagate exception if one occurs member x.Print line = match agent.PostAndReply( fun replyChannel -> Message (Print line, replyChannel) ) with \| None -> () \| Some ex -> raise ex open System.Threading do let main = new Printer(id=1, backup=new Printer(id=2)) (new Thread(fun () -> try main.Print "Humpty Dumpty sat on a wall." main.Print "Humpty Dumpty had a great fall." main.Print "All the king's horses and all the king's men" main.Print "Couldn't put Humpty together again." with \| OutOfInk -> printfn " Humpty Dumpty out of ink!" )).Start() (new Thread(fun () -> try main.Print "Old Mother Goose" main.Print "Would ride through the air" main.Print "On a very fine gander." main.Print "Jack's mother came in," main.Print "And caught the goose soon," main.Print "And mounting its back," main.Print "Flew up to the moon." with \| OutOfInk -> printfn " Mother Goose out of ink!" )).Start() Console.ReadLine() \|> ignore
http://rosettacode.org/wiki/Repeat	Repeat	Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.	#AWK	AWK	# syntax: GAWK -f REPEAT.AWK BEGIN { for (i=0; i<=3; i++) { f = (i % 2 == 0) ? "even" : "odd" @f(i) # indirect function call } exit(0) } function even(n, i) { for (i=1; i<=n; i++) { printf("inside even %d\n",n) } } function odd(n, i) { for (i=1; i<=n; i++) { printf("inside odd %d\n",n) } }
http://rosettacode.org/wiki/Repeat	Repeat	Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.	#Batch_File	Batch File	@echo off :_main setlocal call:_func1 _func2 3 pause>nul exit/b :_func1 setlocal enabledelayedexpansion for /l %%i in (1,1,%2) do call:%1 exit /b :_func2 setlocal echo _func2 has been executed exit /b
http://rosettacode.org/wiki/Rename_a_file	Rename a file	Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)	#AWK	AWK	$ awk 'BEGIN{system("mv input.txt output.txt")}' $ awk 'BEGIN{system("mv docs mydocs")}' $ awk 'BEGIN{system("mv /input.txt /output.txt")}' $ awk 'BEGIN{system("mv docs mydocs")}'
http://rosettacode.org/wiki/Rename_a_file	Rename a file	Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)	#BaCon	BaCon	RENAME "input.txt" TO "output.txt" RENAME "/input.txt" TO "/output.txt" RENAME "docs" TO "mydocs" RENAME "/docs" TO "/mydocs"
http://rosettacode.org/wiki/RIPEMD-160	RIPEMD-160	RIPEMD-160 is another hash function; it computes a 160-bit message digest. There is a RIPEMD-160 home page, with test vectors and pseudocode for RIPEMD-160. For padding the message, RIPEMD-160 acts like MD4 (RFC 1320). Find the RIPEMD-160 message digest of a string of octets. Use the ASCII encoded string “Rosetta Code”. You may either call an RIPEMD-160 library, or implement RIPEMD-160 in your language.	#zkl	zkl	var MsgHash=Import("zklMsgHash"); MsgHash.RIPEMD160("Rosetta Code")
http://rosettacode.org/wiki/Resistor_mesh	Resistor mesh	Task Given 10×10 grid nodes (as shown in the image) interconnected by 1Ω resistors as shown, find the resistance between points A and B. See also (humor, nerd sniping) xkcd.com cartoon	#Nim	Nim	const S = 10 type NodeKind = enum nodeFree, nodeA, nodeB Node = object v: float fixed: NodeKind Mesh[H, W: static int] = array[H, array[W, Node]] func setBoundary(m: var Mesh) = m[1][1].v = 1.0 m[1][1].fixed = nodeA m[6][7].v = -1.0 m[6][7].fixed = nodeB func calcDiff[H, W: static int](m,: Mesh[H, W]; d: var Mesh[H, W]): float = for i in 0..<H: for j in 0..<W: var v = 0.0 var n = 0 if i > 0: v += m[i - 1][j].v inc n if j > 0: v += m[i][j - 1].v inc n if i + 1 < m.H: v += m[i + 1][j].v inc n if j + 1 < m.W: v += m[i][j + 1].v inc n v = m[i][j].v - v / n.toFloat d[i][j].v = v if m[i][j].fixed == nodeFree: result += v * v func iter[H, W: static int](m: var Mesh[H, W]): float = var d: Mesh[H, W] cur: array[NodeKind, float] diff = 1e10 while diff > 1e-24: m.setBoundary() diff = calcDiff(m, d) for i in 0..<H: for j in 0..<W: m[i][j].v -= d[i][j].v for i in 0..<H: for j in 0..<W: var k = 0 if i != 0: inc k if j != 0: inc k if i < m.H - 1: inc k if j < m.W - 1: inc k cur[m[i][j].fixed] += d[i][j].v * k.toFloat result = (cur[nodeA] - cur[nodeB]) / 2 when isMainModule: var mesh: Mesh[S, S] let r = 2 / mesh.iter() echo "R = ", r
http://rosettacode.org/wiki/Respond_to_an_unknown_method_call	Respond to an unknown method call	Task Demonstrate how to make the object respond (sensibly/usefully) to an invocation of a method on it that it does not support through its class definitions. Note that this is not the same as just invoking a defined method whose name is given dynamically; the method named at the point of invocation must not be defined. This task is intended only for object systems that use a dynamic dispatch mechanism without static checking. Related task Send an unknown method call.	#Slate	Slate	define: #shell &builder: [lobby newSubSpace]. _@shell didNotUnderstand: message at: position "Form a command string and execute it." [ position > 0 ifTrue: [resend] ifFalse: [([\| :command \| message selector isUnarySelector ifTrue: [command ; message selector. message optionals pairsDo: [\| :key :value \| command ; ' -' ; (key as: String) allButFirst allButLast ; ' ' ; (value as: String)]]. message selector isKeywordSelector ifTrue: [\| keywords args \| keywords: ((message selector as: String) splitWith: $:). command ; keywords first. keywords size = 1 ifTrue: "Read a string or array of arguments." [args: message arguments second. (args is: String) ifTrue: [command ; ' ' ; args] ifFalse: [args do: [\| :arg \| command ; ' ' ; arg]]]]] writingAs: String) ifNil: [resend] ifNotNilDo: [\| :cmd \| [Platform run: cmd]]] ].
http://rosettacode.org/wiki/Respond_to_an_unknown_method_call	Respond to an unknown method call	Task Demonstrate how to make the object respond (sensibly/usefully) to an invocation of a method on it that it does not support through its class definitions. Note that this is not the same as just invoking a defined method whose name is given dynamically; the method named at the point of invocation must not be defined. This task is intended only for object systems that use a dynamic dispatch mechanism without static checking. Related task Send an unknown method call.	#Smalltalk	Smalltalk	Object subclass: CatchThemAll [ foo [ 'foo received' displayNl ] bar [ 'bar received' displayNl ] doesNotUnderstand: aMessage [ ('message "' , (aMessage selector asString) , '"') displayNl. (aMessage arguments) do: [ :a \| 'argument: ' display. a printNl. ] ] ] \|a\| a := CatchThemAll new. a foo. a bar. a weCanDoIt. a theyCanToo: 'eat' and: 'walk'.
http://rosettacode.org/wiki/Respond_to_an_unknown_method_call	Respond to an unknown method call	Task Demonstrate how to make the object respond (sensibly/usefully) to an invocation of a method on it that it does not support through its class definitions. Note that this is not the same as just invoking a defined method whose name is given dynamically; the method named at the point of invocation must not be defined. This task is intended only for object systems that use a dynamic dispatch mechanism without static checking. Related task Send an unknown method call.	#SuperCollider	SuperCollider	Ingorabilis { tell { "I told you so".postln; } find { "I found nothing".postln } doesNotUnderstand { \|selector ... args\| "Method selector '%' not understood by %\n".postf(selector, this.class); "Giving you some good arguments in the following".postln; args.do { \|x\| x.postln }; "And now I delegate the method to my respected superclass".postln; super.doesNotUnderstand(selector, args) } }
http://rosettacode.org/wiki/Reverse_words_in_a_string	Reverse words in a string	Task Reverse the order of all tokens in each of a number of strings and display the result; the order of characters within a token should not be modified. Example Hey you, Bub! would be shown reversed as: Bub! you, Hey Tokens are any non-space characters separated by spaces (formally, white-space); the visible punctuation form part of the word within which it is located and should not be modified. You may assume that there are no significant non-visible characters in the input. Multiple or superfluous spaces may be compressed into a single space. Some strings have no tokens, so an empty string (or one just containing spaces) would be the result. Display the strings in order (1st, 2nd, 3rd, ···), and one string per line. (You can consider the ten strings as ten lines, and the tokens as words.) Input data (ten lines within the box) line ╔════════════════════════════════════════╗ 1 ║ ---------- Ice and Fire ------------ ║ 2 ║ ║ ◄─── a blank line here. 3 ║ fire, in end will world the say Some ║ 4 ║ ice. in say Some ║ 5 ║ desire of tasted I've what From ║ 6 ║ fire. favor who those with hold I ║ 7 ║ ║ ◄─── a blank line here. 8 ║ ... elided paragraph last ... ║ 9 ║ ║ ◄─── a blank line here. 10 ║ Frost Robert ----------------------- ║ ╚════════════════════════════════════════╝ Cf. Phrase reversals	#CoffeeScript	CoffeeScript	strReversed = '---------- Ice and Fire ------------\n\n fire, in end will world the say Some\n ice. in say Some\n desire of tasted I\'ve what From\n fire. favor who those with hold I\n\n ... elided paragraph last ...\n\n Frost Robert -----------------------' reverseString = (s) -> s.split('\n').map((l) -> l.split(/\s/).reverse().join ' ').join '\n' console.log reverseString(strReversed)
http://rosettacode.org/wiki/Rot-13	Rot-13	Task Implement a rot-13 function (or procedure, class, subroutine, or other "callable" object as appropriate to your programming environment). Optionally wrap this function in a utility program (like tr, which acts like a common UNIX utility, performing a line-by-line rot-13 encoding of every line of input contained in each file listed on its command line, or (if no filenames are passed thereon) acting as a filter on its "standard input." (A number of UNIX scripting languages and utilities, such as awk and sed either default to processing files in this way or have command line switches or modules to easily implement these wrapper semantics, e.g., Perl and Python). The rot-13 encoding is commonly known from the early days of Usenet "Netnews" as a way of obfuscating text to prevent casual reading of spoiler or potentially offensive material. Many news reader and mail user agent programs have built-in rot-13 encoder/decoders or have the ability to feed a message through any external utility script for performing this (or other) actions. The definition of the rot-13 function is to simply replace every letter of the ASCII alphabet with the letter which is "rotated" 13 characters "around" the 26 letter alphabet from its normal cardinal position (wrapping around from z to a as necessary). Thus the letters abc become nop and so on. Technically rot-13 is a "mono-alphabetic substitution cipher" with a trivial "key". A proper implementation should work on upper and lower case letters, preserve case, and pass all non-alphabetic characters in the input stream through without alteration. Related tasks Caesar cipher Substitution Cipher Vigenère Cipher/Cryptanalysis Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#PHP	PHP	echo str_rot13('foo'), "\n";
http://rosettacode.org/wiki/Roman_numerals/Encode	Roman numerals/Encode	Task Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero. In Roman numerals: 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC 2008 is written as 2000=MM, 8=VIII; or MMVIII 1666 uses each Roman symbol in descending order: MDCLXVI	#Oz	Oz	declare fun {Digit X Y Z K} unit([X] [X X] [X X X] [X Y] [Y] [Y X] [Y X X] [Y X X X] [X Z]) .K end fun {ToRoman X} if X == 0 then "" elseif X < 0 then raise toRoman(negativeInput X) end elseif X >= 1000 then "M"#{ToRoman X-1000} elseif X >= 100 then {Digit &C &D &M X div 100}#{ToRoman X mod 100} elseif X >= 10 then {Digit &X &L &C X div 10}#{ToRoman X mod 10} else {Digit &I &V &X X} end end in {ForAll {Map [1999 25 944] ToRoman} System.showInfo}
http://rosettacode.org/wiki/Roman_numerals/Decode	Roman numerals/Decode	Task Create a function that takes a Roman numeral as its argument and returns its value as a numeric decimal integer. You don't need to validate the form of the Roman numeral. Modern Roman numerals are written by expressing each decimal digit of the number to be encoded separately, starting with the leftmost decimal digit and skipping any 0s (zeroes). 1990 is rendered as MCMXC (1000 = M, 900 = CM, 90 = XC) and 2008 is rendered as MMVIII (2000 = MM, 8 = VIII). The Roman numeral for 1666, MDCLXVI, uses each letter in descending order.	#QBasic	QBasic	FUNCTION romToDec (roman$) num = 0 prenum = 0 FOR i = LEN(roman$) TO 1 STEP -1 x$ = MID$(roman$, i, 1) n = 0 IF x$ = "M" THEN n = 1000 IF x$ = "D" THEN n = 500 IF x$ = "C" THEN n = 100 IF x$ = "L" THEN n = 50 IF x$ = "X" THEN n = 10 IF x$ = "V" THEN n = 5 IF x$ = "I" THEN n = 1 IF n < preNum THEN num = num - n ELSE num = num + n preNum = n NEXT i romToDec = num END FUNCTION !Testing PRINT "MCMXCIX = "; romToDec("MCMXCIX") '1999 PRINT "MDCLXVI = "; romToDec("MDCLXVI") '1666 PRINT "XXV = "; romToDec("XXV") '25 PRINT "CMLIV = "; romToDec("CMLIV") '954 PRINT "MMXI = "; romToDec("MMXI") '2011
http://rosettacode.org/wiki/Run-length_encoding	Run-length encoding	Run-length encoding You are encouraged to solve this task according to the task description, using any language you may know. Task Given a string containing uppercase characters (A-Z), compress repeated 'runs' of the same character by storing the length of that run, and provide a function to reverse the compression. The output can be anything, as long as you can recreate the input with it. Example Input: WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW Output: 12W1B12W3B24W1B14W Note: the encoding step in the above example is the same as a step of the Look-and-say sequence.	#Wren	Wren	import "/pattern" for Pattern var p = Pattern.new("/u") // match any upper case letter var encode = Fn.new { \|s\| if (s == "") return s var e = "" var curr = s[0] var count = 1 var i = 1 while (i < s.count) { if (s[i] == curr) { count = count + 1 } else { e = e + count.toString + curr curr = s[i] count = 1 } i = i + 1 } return e + count.toString + curr } var decode = Fn.new { \|e\| if (e == "") return e var letters = Pattern.matchesText(p.findAll(e)) var numbers = p.splitAll(e)[0..-2].map { \|s\| Num.fromString(s) }.toList return (0...letters.count).reduce("") { \|acc, i\| acc + letters[i]*numbers[i] }.join() } var strings = [ "AA", "RROSETTAA", "WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW" ] for (s in strings) { System.print("Original text : %(s)") var e = encode.call(s) System.print("Encoded text : %(e)") var d = decode.call(e) System.print("Decoded text : %(d)") System.print("Original = decoded : %(s == d)\n") }
http://rosettacode.org/wiki/Repeat_a_string	Repeat a string	Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("", 5) => "****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#AutoHotkey	AutoHotkey	MsgBox % Repeat("ha",5) Repeat(String,Times) { Loop, %Times% Output .= String Return Output }
http://rosettacode.org/wiki/Return_multiple_values	Return multiple values	Task Show how to return more than one value from a function.	#COBOL	COBOL	identification division. program-id. multiple-values. environment division. configuration section. repository. function multiples function all intrinsic. REPLACE ==:linked-items:== BY == 01 a usage binary-long. 01 b pic x(10). 01 c usage float-short. == ==:record-item:== BY == 01 master. 05 ma usage binary-long. 05 mb pic x(10). 05 mc usage float-short. ==. data division. working-storage section. :linked-items: :record-item: procedure division. sample-main. move 41 to a move "aaaaabbbbb" to b move function e to c display "Original: " a ", " b ", " c call "subprogram" using a b c display "Modified: " a ", " b ", " c move multiples() to master display "Multiple: " ma ", " mb ", " mc goback. end program multiple-values. > subprogram identification division. program-id. subprogram. data division. linkage section. :linked-items: procedure division using a b c. add 1 to a inspect b converting "a" to "b" divide 2 into c goback. end program subprogram. > multiples function identification division. function-id. multiples. data division. linkage section. :record-item: procedure division returning master. move 84 to ma move "multiple" to mb move function pi to mc goback. end function multiples.
http://rosettacode.org/wiki/Remove_duplicate_elements	Remove duplicate elements	Sorting Algorithm This is a sorting algorithm. It may be applied to a set of data in order to sort it. For comparing various sorts, see compare sorts. For other sorting algorithms, see sorting algorithms, or: O(n logn) sorts Heap sort \| Merge sort \| Patience sort \| Quick sort O(n log2n) sorts Shell Sort O(n2) sorts Bubble sort \| Cocktail sort \| Cocktail sort with shifting bounds \| Comb sort \| Cycle sort \| Gnome sort \| Insertion sort \| Selection sort \| Strand sort other sorts Bead sort \| Bogo sort \| Common sorted list \| Composite structures sort \| Custom comparator sort \| Counting sort \| Disjoint sublist sort \| External sort \| Jort sort \| Lexicographical sort \| Natural sorting \| Order by pair comparisons \| Order disjoint list items \| Order two numerical lists \| Object identifier (OID) sort \| Pancake sort \| Quickselect \| Permutation sort \| Radix sort \| Ranking methods \| Remove duplicate elements \| Sleep sort \| Stooge sort \| [Sort letters of a string] \| Three variable sort \| Topological sort \| Tree sort Given an Array, derive a sequence of elements in which all duplicates are removed. There are basically three approaches seen here: Put the elements into a hash table which does not allow duplicates. The complexity is O(n) on average, and O(n2) worst case. This approach requires a hash function for your type (which is compatible with equality), either built-in to your language, or provided by the user. Sort the elements and remove consecutive duplicate elements. The complexity of the best sorting algorithms is O(n log n). This approach requires that your type be "comparable", i.e., have an ordering. Putting the elements into a self-balancing binary search tree is a special case of sorting. Go through the list, and for each element, check the rest of the list to see if it appears again, and discard it if it does. The complexity is O(n2). The up-shot is that this always works on any type (provided that you can test for equality).	#11l	11l	V items = [‘1’, ‘2’, ‘3’, ‘a’, ‘b’, ‘c’, ‘2’, ‘3’, ‘4’, ‘b’, ‘c’, ‘d’] V unique = Array(Set(items)) print(unique)
http://rosettacode.org/wiki/Reflection/List_properties	Reflection/List properties	Task The goal is to get the properties of an object, as names, values or both. Some languages support dynamic properties, which in general can only be inspected if a class' public API includes a way of listing them.	#C.23	C#	using System; using System.Collections.Generic; using System.Linq; using System.Reflection; public static class Reflection { public static void Main() { var t = new TestClass(); var flags = BindingFlags.Public \| BindingFlags.NonPublic \| BindingFlags.Instance; foreach (var prop in GetPropertyValues(t, flags)) { Console.WriteLine(prop); } foreach (var field in GetFieldValues(t, flags)) { Console.WriteLine(field); } } public static IEnumerable<(string name, object value)> GetPropertyValues<T>(T obj, BindingFlags flags) => from p in typeof(T).GetProperties(flags) where p.GetIndexParameters().Length == 0 //To filter out indexers select (p.Name, p.GetValue(obj, null)); public static IEnumerable<(string name, object value)> GetFieldValues<T>(T obj, BindingFlags flags) => typeof(T).GetFields(flags).Select(f => (f.Name, f.GetValue(obj))); class TestClass { private int privateField = 7; public int PublicNumber { get; } = 4; private int PrivateNumber { get; } = 2; } }
http://rosettacode.org/wiki/Rep-string	Rep-string	Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#APL	APL	rep ← ⊢ (⊢(/⍨)(⊂⊣)≡¨(≢⊣)⍴¨⊢) ⍳∘(⌊0.5×≢)↑¨⊂
http://rosettacode.org/wiki/Rep-string	Rep-string	Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#AppleScript	AppleScript	------------------------REP-CYCLES------------------------- -- repCycles :: String -> [String] on repCycles(xs) set n to length of xs script isCycle on \|λ\|(cs) xs = takeCycle(n, cs) end \|λ\| end script filter(isCycle, tail(inits(take(quot(n, 2), xs)))) end repCycles -- cycleReport :: String -> [String] on cycleReport(xs) set reps to repCycles(xs) if isNull(reps) then {xs, "(n/a)"} else {xs, item -1 of reps} end if end cycleReport ---------------------------TEST---------------------------- on run set samples to {"1001110011", "1110111011", "0010010010", ¬ "1010101010", "1111111111", "0100101101", "0100100", ¬ "101", "11", "00", "1"} unlines(cons("Longest cycle:" & linefeed, ¬ map(intercalate(" -> "), ¬ map(cycleReport, samples)))) end run ---------------------GENERIC FUNCTIONS--------------------- -- concat :: [[a]] -> [a] \| [String] -> String on concat(xs) if length of xs > 0 and class of (item 1 of xs) is string then set acc to "" else set acc to {} end if repeat with i from 1 to length of xs set acc to acc & item i of xs end repeat acc end concat -- cons :: a -> [a] -> [a] on cons(x, xs) {x} & xs end cons -- filter :: (a -> Bool) -> [a] -> [a] on filter(f, xs) tell mReturn(f) set lst to {} set lng to length of xs repeat with i from 1 to lng set v to item i of xs if \|λ\|(v, i, xs) then set end of lst to v end repeat return lst end tell end filter -- foldl :: (a -> b -> a) -> a -> [b] -> a on foldl(f, startValue, xs) tell mReturn(f) set v to startValue set lng to length of xs repeat with i from 1 to lng set v to \|λ\|(v, item i of xs, i, xs) end repeat return v end tell end foldl -- inits :: [a] -> [[a]] -- inits :: String -> [String] on inits(xs) script elemInit on \|λ\|(_, i, xs) items 1 thru i of xs end \|λ\| end script script charInit on \|λ\|(_, i, xs) text 1 thru i of xs end \|λ\| end script if class of xs is string then {""} & map(charInit, xs) else {{}} & map(elemInit, xs) end if end inits -- intercalate :: Text -> [Text] -> Text on intercalate(strText) script on \|λ\|(xs) set {dlm, my text item delimiters} to {my text item delimiters, strText} set strJoined to xs as text set my text item delimiters to dlm return strJoined end \|λ\| end script end intercalate -- map :: (a -> b) -> [a] -> [b] on map(f, xs) tell mReturn(f) set lng to length of xs set lst to {} repeat with i from 1 to lng set end of lst to \|λ\|(item i of xs, i, xs) end repeat return lst end tell end map -- Lift 2nd class handler function into 1st class script wrapper -- mReturn :: Handler -> Script on mReturn(f) if class of f is script then f else script property \|λ\| : f end script end if end mReturn -- isNull :: [a] -> Bool on isNull(xs) xs = {} end isNull -- min :: Ord a => a -> a -> a on min(x, y) if y < x then y else x end if end min -- quot :: Integral a => a -> a -> a on quot(n, m) n div m end quot -- replicate :: Int -> a -> [a] on replicate(n, a) set out to {} if n < 1 then return out set dbl to {a} repeat while (n > 1) if (n mod 2) > 0 then set out to out & dbl set n to (n div 2) set dbl to (dbl & dbl) end repeat return out & dbl end replicate -- tail :: [a] -> [a] on tail(xs) if length of xs > 1 then items 2 thru -1 of xs else {} end if end tail -- take :: Int -> [a] -> [a] on take(n, xs) if class of xs is string then if n > 0 then text 1 thru min(n, length of xs) of xs else "" end if else if n > 0 then items 1 thru min(n, length of xs) of xs else {} end if end if end take -- takeCycle :: Int -> [a] -> [a] on takeCycle(n, xs) set lng to length of xs if lng ≥ n then set cycle to xs else set cycle to concat(replicate((n div lng) + 1, xs)) end if if class of xs is string then items 1 thru n of cycle as string else items 1 thru n of cycle end if end takeCycle -- unlines :: [String] -> String on unlines(xs) \|λ\|(xs) of intercalate(linefeed) end unlines
http://rosettacode.org/wiki/Reflection/Get_source	Reflection/Get source	Task The goal is to get the source code or file path and line number where a programming object (e.g. module, class, function, method) is defined.	#6502_Assembly	6502 Assembly	LDA #<foo sta $00 LDA #>foo sta $01 jsr PrintBytecode foo: ;do stuff rts PrintBytecode: ldy #0 lda $01 ;high byte of starting address of the source jsr PrintHex ;unimplemented routine that separates the "nibbles" of the accumulator, ; adds $30 or $37 to each depending on if it's 0-9 or A-F respectively, which converts hex to ASCII, ; then prints the high nibble then the low. lda $00 ;low byte of the starting address of the source jsr PrintHex jsr NewLine ;unimplemented new line routine loop: lda ($00),y cmp #$60 beq Terminated jsr PrintHex jmp loop Terminated: jsr PrintHex ;print the last instruction of the routine. rts
http://rosettacode.org/wiki/Reflection/Get_source	Reflection/Get source	Task The goal is to get the source code or file path and line number where a programming object (e.g. module, class, function, method) is defined.	#Clojure	Clojure	; Use source function for source code. (source println) ; Use meta function for filenames and line numbers (and other metadata) (meta #'println)
http://rosettacode.org/wiki/Regular_expressions	Regular expressions	Task match a string against a regular expression substitute part of a string using a regular expression	#Amazing_Hopper	Amazing Hopper	#include <hopper.h> main: expReg="[A-Z]{1,2}[0-9][0-9A-Z]? +[0-9][A-Z]{2}" flag compile = REG_EXTENDED flag match=0 número de matches=10, T1=0 {flag compile,expReg} reg compile(T1) // compile regular expression, pointed whit T1 {flag match,número de matches,T1,"We are at SN12 7NY for this course"},reg match, // execute println reg free(T1) // free pointer to regular expression compiled. exit(0)
http://rosettacode.org/wiki/Regular_expressions	Regular expressions	Task match a string against a regular expression substitute part of a string using a regular expression	#AppleScript	AppleScript	try find text ".*string$" in "I am a string" with regexp on error message return message end try try change "original" into "modified" in "I am the original string" with regexp on error message return message end try
http://rosettacode.org/wiki/Reverse_a_string	Reverse a string	Task Take a string and reverse it. For example, "asdf" becomes "fdsa". Extra credit Preserve Unicode combining characters. For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa". Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#Action.21	Action!	PROC Reverse(CHAR ARRAY src,dst) BYTE i,j i=1 j=src(0) dst(0)=j WHILE j>0 DO dst(j)=src(i) i==+1 j==-1 OD RETURN PROC Test(CHAR ARRAY src) CHAR ARRAY dst(40) Reverse(src,dst) PrintF("'%S' -> '%S'%E",src,dst) RETURN PROC Main() Test("Hello World!") Test("123456789") Test("!noitcA iratA") RETURN
http://rosettacode.org/wiki/Rendezvous	Rendezvous	Demonstrate the “rendezvous” communications technique by implementing a printer monitor.	#Go	Go	package main import ( "errors" "fmt" "strings" "sync" ) var hdText = `Humpty Dumpty sat on a wall. Humpty Dumpty had a great fall. All the king's horses and all the king's men, Couldn't put Humpty together again.` var mgText = `Old Mother Goose, When she wanted to wander, Would ride through the air, On a very fine gander. Jack's mother came in, And caught the goose soon, And mounting its back, Flew up to the moon.` func main() { reservePrinter := startMonitor(newPrinter(5), nil) mainPrinter := startMonitor(newPrinter(5), reservePrinter) var busy sync.WaitGroup busy.Add(2) go writer(mainPrinter, "hd", hdText, &busy) go writer(mainPrinter, "mg", mgText, &busy) busy.Wait() } // printer is a type representing an abstraction of a physical printer. // It is a type defintion for a function that takes a string to print // and returns an error value, (hopefully usually nil, meaning no error.) type printer func(string) error // newPrinter is a constructor. The parameter is a quantity of ink. It // returns a printer object encapsulating the ink quantity. // Note that this is not creating the monitor, only the object serving as // a physical printer by writing to standard output. func newPrinter(ink int) printer { return func(line string) error { if ink == 0 { return eOutOfInk } for _, c := range line { fmt.Printf("%c", c) } fmt.Println() ink-- return nil } } var eOutOfInk = errors.New("out of ink") // For the language task, rSync is a type used to approximate the Ada // rendezvous mechanism that includes the caller waiting for completion // of the callee. For this use case, we signal completion with an error // value as a response. Exceptions are not idiomatic in Go and there is // no attempt here to model the Ada exception mechanism. Instead, it is // idomatic in Go to return error values. Sending an error value on a // channel works well here to signal completion. Go unbuffered channels // provide synchronous rendezvous, but call and response takes two channels, // which are bundled together here in a struct. The channel types are chosen // to mirror the parameter and return types of "type printer" defined above. // The channel types here, string and error are both "reference types" // in Go terminology. That is, they are small things containing pointers // to the actual data. Sending one on a channel does not involve copying, // or much less marshalling string data. type rSync struct { call chan string response chan error } // "rendezvous Print" requested by use case task. // For the language task though, it is implemented here as a method on // rSync that sends its argument on rSync.call and returns the result // received from rSync.response. Each channel operation is synchronous. // The two operations back to back approximate the Ada rendezvous. func (r rSync) print(data string) error { r.call <- data // blocks until data is accepted on channel return <-r.response // blocks until response is received } // monitor is run as a goroutine. It encapsulates the printer passed to it. // Print requests are received through the rSync object "entry," named entry // here to correspond to the Ada concept of an entry point. func monitor(hardPrint printer, entry, reserve rSync) { for { // The monitor goroutine will block here waiting for a "call" // to its "entry point." data := <-entry.call // Assuming the call came from a goroutine calling rSync.print, // that goroutine is now blocked, waiting for this one to send // a response. // attempt output switch err := hardPrint(data); { // consider return value from attempt case err == nil: entry.response <- nil // no problems case err == eOutOfInk && reserve != nil: // Requeue to "entry point" of reserve printer monitor. // Caller stays blocked, and now this goroutine blocks until // it gets a response from the reserve printer monitor. // It then transparently relays the response to the caller. entry.response <- reserve.print(data) default: entry.response <- err // return failure } // The response is away. Loop, and so immediately block again. } } // startMonitor can be seen as an rSync constructor. It also // of course, starts the monitor for which the rSync serves as entry point. // Further to the langauge task, note that the channels created here are // unbuffered. There is no buffer or message box to hold channel data. // A sender will block waiting for a receiver to accept data synchronously. func startMonitor(p printer, reservePrinter rSync) rSync { entry := &rSync{make(chan string), make(chan error)} go monitor(p, entry, reservePrinter) return entry } // Two writer tasks are started as goroutines by main. They run concurrently // and compete for printers as resources. Note the call to "rendezvous Print" // as requested in the use case task and compare the syntax, // Here: printMonitor.print(line); // Ada solution: Main.Print ("string literal"); func writer(printMonitor rSync, id, text string, busy sync.WaitGroup) { for _, line := range strings.Split(text, "\n") { if err := printMonitor.print(line); err != nil { fmt.Printf("** writer task %q terminated: %v **\n", id, err) break } } busy.Done() }
http://rosettacode.org/wiki/Repeat	Repeat	Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.	#BQN	BQN	•Show {2+𝕩}⍟3 1 _repeat_ ← {(𝕘>0)◶⊢‿(𝔽_𝕣_(𝕘-1)𝔽)𝕩} •Show {2+𝕩} _repeat_ 3 1
http://rosettacode.org/wiki/Repeat	Repeat	Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.	#C	C	#include <stdio.h> void repeat(void (f)(void), unsigned int n) { while (n-->0) (f)(); //or just f() } void example() { printf("Example\n"); } int main(int argc, char *argv[]) { repeat(example, 4); return 0; }
http://rosettacode.org/wiki/Rename_a_file	Rename a file	Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)	#BASIC	BASIC	NAME "input.txt" AS "output.txt" NAME "\input.txt" AS "\output.txt" NAME "docs" AS "mydocs" NAME "\docs" AS "\mydocs"
http://rosettacode.org/wiki/Rename_a_file	Rename a file	Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)	#Batch_File	Batch File	ren input.txt output.txt ren \input.txt output.txt ren docs mydocs ren \docs mydocs
http://rosettacode.org/wiki/Resistor_mesh	Resistor mesh	Task Given 10×10 grid nodes (as shown in the image) interconnected by 1Ω resistors as shown, find the resistance between points A and B. See also (humor, nerd sniping) xkcd.com cartoon	#Octave	Octave	N = 10; NN = NN; G = sparse(NN, NN); node = 0; for row=1:N; for col=1:N; node++; if row > 1 G(node, node)++; G(node, node - N) = -1; end if row < N; G(node, node)++; G(node, node + N) = -1; end if col > 1 G(node, node)++; G(node, node - 1) = -1; end if col < N; G(node, node)++; G(node, node + 1) = -1; end end end current = sparse(NN, 1); Ar = 2; Ac = 2; A = Ac + N( Ar - 1 ); Br = 7; Bc = 8; B = Bc + N*( Br - 1 ); current( A ) = -1; current( B ) = +1; voltage = G \ current; VA = voltage( A ); VB = voltage( B ); full( abs( VA - VB ) )
http://rosettacode.org/wiki/Respond_to_an_unknown_method_call	Respond to an unknown method call	Task Demonstrate how to make the object respond (sensibly/usefully) to an invocation of a method on it that it does not support through its class definitions. Note that this is not the same as just invoking a defined method whose name is given dynamically; the method named at the point of invocation must not be defined. This task is intended only for object systems that use a dynamic dispatch mechanism without static checking. Related task Send an unknown method call.	#Tcl	Tcl	package require TclOO # First create a simple, conventional class and object oo::class create Example { method foo {} { puts "this is foo" } method bar {} { puts "this is bar" } } Example create example # Modify the object to have a custom ‘unknown method’ interceptor oo::objdefine example { method unknown {name args} { puts "tried to handle unknown method \"$name\"" if {[llength $args]} { puts "it had arguments: $args" } } } # Show off what we can now do... example foo; # prints “this is foo” example bar; # prints “this is bar” example grill; # prints “tried to handle unknown method "grill"” example ding dong; # prints “tried to handle unknown method "ding"” # prints “it had arguments: dong”
http://rosettacode.org/wiki/Respond_to_an_unknown_method_call	Respond to an unknown method call	Task Demonstrate how to make the object respond (sensibly/usefully) to an invocation of a method on it that it does not support through its class definitions. Note that this is not the same as just invoking a defined method whose name is given dynamically; the method named at the point of invocation must not be defined. This task is intended only for object systems that use a dynamic dispatch mechanism without static checking. Related task Send an unknown method call.	#UNIX_Shell	UNIX Shell	function handle_error { status=$? # 127 is: command not found if [[ $status -ne 127 ]]; then return fi lastcmd=$(history \| tail -1 \| sed 's/^ [0-9] *//') read cmd args <<< "$lastcmd" echo "you tried to call $cmd" } # Trap errors. trap 'handle_error' ERR
http://rosettacode.org/wiki/Reverse_words_in_a_string	Reverse words in a string	Task Reverse the order of all tokens in each of a number of strings and display the result; the order of characters within a token should not be modified. Example Hey you, Bub! would be shown reversed as: Bub! you, Hey Tokens are any non-space characters separated by spaces (formally, white-space); the visible punctuation form part of the word within which it is located and should not be modified. You may assume that there are no significant non-visible characters in the input. Multiple or superfluous spaces may be compressed into a single space. Some strings have no tokens, so an empty string (or one just containing spaces) would be the result. Display the strings in order (1st, 2nd, 3rd, ···), and one string per line. (You can consider the ten strings as ten lines, and the tokens as words.) Input data (ten lines within the box) line ╔════════════════════════════════════════╗ 1 ║ ---------- Ice and Fire ------------ ║ 2 ║ ║ ◄─── a blank line here. 3 ║ fire, in end will world the say Some ║ 4 ║ ice. in say Some ║ 5 ║ desire of tasted I've what From ║ 6 ║ fire. favor who those with hold I ║ 7 ║ ║ ◄─── a blank line here. 8 ║ ... elided paragraph last ... ║ 9 ║ ║ ◄─── a blank line here. 10 ║ Frost Robert ----------------------- ║ ╚════════════════════════════════════════╝ Cf. Phrase reversals	#Common_Lisp	Common Lisp	(defun split-and-reverse (str) (labels ((iter (s lst) (let ((s2 (string-trim '(#\space) s))) (if s2 (let ((word-end (position #\space s2))) (if (and word-end (< (1+ word-end) (length s2))) (iter (subseq s2 (1+ word-end)) (cons (subseq s2 0 word-end) lst)) (cons s2 lst))) lst)))) (iter str NIL))) (defparameter poem "---------- Ice and Fire ------------ fire, in end will world the say Some ice. in say Some desire of tasted I've what From fire. favor who those with hold I ... elided paragraph last ... Frost Robert -----------------------") (with-input-from-string (s poem) (loop for line = (read-line s NIL) while line do (format t "~{~a~#[~:; ~]~}~%" (split-and-reverse line))))
http://rosettacode.org/wiki/Rot-13	Rot-13	Task Implement a rot-13 function (or procedure, class, subroutine, or other "callable" object as appropriate to your programming environment). Optionally wrap this function in a utility program (like tr, which acts like a common UNIX utility, performing a line-by-line rot-13 encoding of every line of input contained in each file listed on its command line, or (if no filenames are passed thereon) acting as a filter on its "standard input." (A number of UNIX scripting languages and utilities, such as awk and sed either default to processing files in this way or have command line switches or modules to easily implement these wrapper semantics, e.g., Perl and Python). The rot-13 encoding is commonly known from the early days of Usenet "Netnews" as a way of obfuscating text to prevent casual reading of spoiler or potentially offensive material. Many news reader and mail user agent programs have built-in rot-13 encoder/decoders or have the ability to feed a message through any external utility script for performing this (or other) actions. The definition of the rot-13 function is to simply replace every letter of the ASCII alphabet with the letter which is "rotated" 13 characters "around" the 26 letter alphabet from its normal cardinal position (wrapping around from z to a as necessary). Thus the letters abc become nop and so on. Technically rot-13 is a "mono-alphabetic substitution cipher" with a trivial "key". A proper implementation should work on upper and lower case letters, preserve case, and pass all non-alphabetic characters in the input stream through without alteration. Related tasks Caesar cipher Substitution Cipher Vigenère Cipher/Cryptanalysis Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#Picat	Picat	go => S = "Big fjords vex quick waltz nymph!", println(S), println(rot13(S)), println(rot13(rot13(S))), nl. % Rot 13 using a map rot13(S) = S2 => lower(Lower), upper(Upper), M = create_map(Lower, Upper), % If a char is not in a..zA..z then show it as it is. S2 := [M.get(C,C) : C in S]. create_map(Lower, Upper) = M => M = new_map(), Len = Lower.length, LDiv := Lower.length div 2, foreach(I in 1..Len) II = (LDiv+I) mod Len, if II == 0 then II := Len end, M.put(Upper[I],Upper[II]), M.put(Lower[I],Lower[II]) end. lower("abcdefghijklmnopqrstuvwxyz"). upper("ABCDEFGHIJKLMNOPQRSTUVWXYZ").
http://rosettacode.org/wiki/Roman_numerals/Encode	Roman numerals/Encode	Task Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero. In Roman numerals: 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC 2008 is written as 2000=MM, 8=VIII; or MMVIII 1666 uses each Roman symbol in descending order: MDCLXVI	#PARI.2FGP	PARI/GP	oldRoman(n)={ while(n>999999, n-=1000000; print1("((((I))))") ); if(n>499999, n-=500000; print1("I))))") ); while(n>99999, n-=100000; print1("(((I)))") ); if(n>49999, n-=50000; print1("I)))") ); while(n>9999, n-=10000; print1("((I))") ); if(n>4999, n-=5000; print1("I))") ); while(n>999, n-=1000; print1("(I)") ); if(n>499, n-=500; print1("I)") ); while(n>99, n-=100; print1("C") ); if(n>49, n-=50; print1("L"); ); while(n>9, n-=10; print1("X") ); if(n>4, n-=5; print1("V"); ); while(n, n--; print1("I") ); print() };
http://rosettacode.org/wiki/Roman_numerals/Decode	Roman numerals/Decode	Task Create a function that takes a Roman numeral as its argument and returns its value as a numeric decimal integer. You don't need to validate the form of the Roman numeral. Modern Roman numerals are written by expressing each decimal digit of the number to be encoded separately, starting with the leftmost decimal digit and skipping any 0s (zeroes). 1990 is rendered as MCMXC (1000 = M, 900 = CM, 90 = XC) and 2008 is rendered as MMVIII (2000 = MM, 8 = VIII). The Roman numeral for 1666, MDCLXVI, uses each letter in descending order.	#Quackery	Quackery	[ 2dup < if [ dip [ 2 * - ] dup ] nip dup rot + swap ] is roman ( t p n --> t p ) [ 1 roman ] is I ( t p --> t p ) [ 5 roman ] is V ( t p --> t p ) [ 10 roman ] is X ( t p --> t p ) [ 50 roman ] is L ( t p --> t p ) [ 100 roman ] is C ( t p --> t p ) [ 500 roman ] is D ( t p --> t p ) [ 1000 roman ] is M ( t p --> t p ) [ 0 1000 rot $ "" swap witheach [ space join join ] quackery drop ] is ->arabic ( $ --> n ) $ " MCMXC" dup echo$ say " = " ->arabic echo cr $ " MMVIII" dup echo$ say " = " ->arabic echo cr $ "MDCLXVI" dup echo$ say " = " ->arabic echo cr cr $ "I MIX VIVID MILD MIMIC" dup echo$ say " = " ->arabic echo cr
http://rosettacode.org/wiki/Run-length_encoding	Run-length encoding	Run-length encoding You are encouraged to solve this task according to the task description, using any language you may know. Task Given a string containing uppercase characters (A-Z), compress repeated 'runs' of the same character by storing the length of that run, and provide a function to reverse the compression. The output can be anything, as long as you can recreate the input with it. Example Input: WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW Output: 12W1B12W3B24W1B14W Note: the encoding step in the above example is the same as a step of the Look-and-say sequence.	#XPL0	XPL0	include c:\cxpl\codes; \intrinsic 'code' declarations string 0; \use zero-terminated strings, instead of MSb terminated proc Compress(S); \Compress string using run-length encoding, & display it char S; int I, C0, C, N; [I:= 0; C0:= S(I); I:= I+1; repeat ChOut(0, C0); N:= 0; repeat C:= S(I); I:= I+1; N:= N+1; until C#C0; if N>1 then IntOut(0, N-1); C0:= C; until C=0; ]; \Compress proc Expand(S); \Expand compressed string, and display it char S; int I, C0, C, N; [I:= 0; C0:= S(I); I:= I+1; repeat ChOut(0, C0); C:= S(I); I:= I+1; if C>=^1 & C<=^9 then [N:= 0; while C>=^0 & C<=^9 do [N:= N*10 + C-^0; C:= S(I); I:= I+1; ]; while N do [ChOut(0, C0); N:= N-1]; ]; C0:= C; until C=0; ]; \Expand [Compress("WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW"); CrLf(0); Expand("W11BW11B2W23BW13"); CrLf(0); ]
http://rosettacode.org/wiki/Repeat_a_string	Repeat a string	Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("", 5) => "****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#AutoIt	AutoIt	#include <String.au3> ConsoleWrite(_StringRepeat("ha", 5) & @CRLF)
http://rosettacode.org/wiki/Return_multiple_values	Return multiple values	Task Show how to return more than one value from a function.	#Common_Lisp	Common Lisp	(defun return-three () 3)
http://rosettacode.org/wiki/Return_multiple_values	Return multiple values	Task Show how to return more than one value from a function.	#Cowgol	Cowgol	include "cowgol.coh"; # In Cowgol, subroutines can simply define multiple output parameters. sub MinMax(arr: [uint8], len: intptr): (min: uint8, max: uint8) is min := 255; max := 0; while len > 0 loop len := len - 1; var cur := [arr]; if min > cur then min := cur; end if; if max < cur then max := cur; end if; arr := @next arr; end loop; # Values are also returned automatically. end sub; # Example of usage: var nums: uint8[] := {23, 65, 33, 12, 95, 5, 32, 91, 135, 25, 8}; var least: uint8; var most: uint8; # Accept two output parameters from a function (least, most) := MinMax(&nums[0], @sizeof nums); print("Min: "); print_i8(least); print_nl(); print("Max: "); print_i8(most); print_nl();
http://rosettacode.org/wiki/Remove_duplicate_elements	Remove duplicate elements	Sorting Algorithm This is a sorting algorithm. It may be applied to a set of data in order to sort it. For comparing various sorts, see compare sorts. For other sorting algorithms, see sorting algorithms, or: O(n logn) sorts Heap sort \| Merge sort \| Patience sort \| Quick sort O(n log2n) sorts Shell Sort O(n2) sorts Bubble sort \| Cocktail sort \| Cocktail sort with shifting bounds \| Comb sort \| Cycle sort \| Gnome sort \| Insertion sort \| Selection sort \| Strand sort other sorts Bead sort \| Bogo sort \| Common sorted list \| Composite structures sort \| Custom comparator sort \| Counting sort \| Disjoint sublist sort \| External sort \| Jort sort \| Lexicographical sort \| Natural sorting \| Order by pair comparisons \| Order disjoint list items \| Order two numerical lists \| Object identifier (OID) sort \| Pancake sort \| Quickselect \| Permutation sort \| Radix sort \| Ranking methods \| Remove duplicate elements \| Sleep sort \| Stooge sort \| [Sort letters of a string] \| Three variable sort \| Topological sort \| Tree sort Given an Array, derive a sequence of elements in which all duplicates are removed. There are basically three approaches seen here: Put the elements into a hash table which does not allow duplicates. The complexity is O(n) on average, and O(n2) worst case. This approach requires a hash function for your type (which is compatible with equality), either built-in to your language, or provided by the user. Sort the elements and remove consecutive duplicate elements. The complexity of the best sorting algorithms is O(n log n). This approach requires that your type be "comparable", i.e., have an ordering. Putting the elements into a self-balancing binary search tree is a special case of sorting. Go through the list, and for each element, check the rest of the list to see if it appears again, and discard it if it does. The complexity is O(n2). The up-shot is that this always works on any type (provided that you can test for equality).	#360_Assembly	360 Assembly	* Remove duplicate elements - 18/10/2015 REMDUP CSECT USING REMDUP,R15 set base register SR R6,R6 i=0 LA R8,1 k=1 LOOPK C R8,N do k=1 to n BH ELOOPK LR R1,R8 k SLA R1,2 L R9,T-4(R1) e=t(k) LR R7,R8 k BCTR R7,0 j=k-1 LOOPJ C R7,=F'1' do j=k-1 to 1 by -1 BL ELOOPJ LR R1,R7 j SLA R1,2 L R2,T-4(R1) t(j) CR R9,R2 if e=t(j) then goto iter BE ITER BCTR R7,0 j=j-1 B LOOPJ ELOOPJ LA R6,1(R6) i=i+1 LR R1,R6 i SLA R1,2 ST R9,T-4(R1) t(i)=e ITER LA R8,1(R8) k=k+1 B LOOPK ELOOPK LA R10,PG pgi=@pg LA R8,1 k=1 LOOP CR R8,R6 do k=1 to i BH ELOOP LR R1,R8 k SLA R1,2 L R2,T-4(R1) t(k) XDECO R2,PG+80 edit t(k) MVC 0(3,R10),PG+89 output t(k) on 3 char LA R10,3(R10) pgi=pgi+3 LA R8,1(R8) k=k+1 B LOOP ELOOP XPRNT PG,80 print buffer XR R15,R15 set return code BR R14 return to caller T DC F'6',F'6',F'1',F'5',F'6',F'2',F'1',F'7',F'5',F'22' DC F'4',F'19',F'1',F'1',F'6',F'8',F'9',F'10',F'11',F'12' N DC A((N-T)/4) number of T items PG DC CL92' ' YREGS END REMDUP
http://rosettacode.org/wiki/Reflection/List_properties	Reflection/List properties	Task The goal is to get the properties of an object, as names, values or both. Some languages support dynamic properties, which in general can only be inspected if a class' public API includes a way of listing them.	#D	D	import std.stdio; struct S { bool b; void foo() {} private void bar() {} } class C { bool b; void foo() {} private void bar() {} } void printProperties(T)() if (is(T == class) \|\| is(T == struct)) { import std.stdio; import std.traits; writeln("Properties of ", T.stringof, ':'); foreach (m; __traits(allMembers, T)) { static if (__traits(compiles, (typeof(__traits(getMember, T, m))))) { alias typeof(__traits(getMember, T, m)) ti; static if (!isFunction!ti) { writeln(" ", m); } } } } void main() { printProperties!S; printProperties!C; }
http://rosettacode.org/wiki/Reflection/List_properties	Reflection/List properties	Task The goal is to get the properties of an object, as names, values or both. Some languages support dynamic properties, which in general can only be inspected if a class' public API includes a way of listing them.	#Elena	Elena	import system'routines; import system'dynamic; import extensions; class MyClass { prop int X; prop string Y; } public program() { var o := new MyClass { this X := 2; this Y := "String"; }; MyClass.__getProperties().forEach:(p) { console.printLine("o.",p,"=",cast MessageName(p).getPropertyValue(o)) } }
http://rosettacode.org/wiki/Rep-string	Rep-string	Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#Arturo	Arturo	repeated?: function [text][ loop ((size text)/2)..0 'x [ if prefix? text slice text x (size text)-1 [ (x>0)? -> return slice text 0 x-1 -> return false ] ] return false ] strings: { 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 } loop split.lines strings 'str [ rep: repeated? str if? false = rep -> print [str "-> not a rep-string"] else -> print [str "->" rep "( length:" size rep ")"] ]
http://rosettacode.org/wiki/Reflection/Get_source	Reflection/Get source	Task The goal is to get the source code or file path and line number where a programming object (e.g. module, class, function, method) is defined.	#Factor	Factor	USE: see \ integer see ! class nl \ dip see ! word
http://rosettacode.org/wiki/Reflection/Get_source	Reflection/Get source	Task The goal is to get the source code or file path and line number where a programming object (e.g. module, class, function, method) is defined.	#FreeBASIC	FreeBASIC	' FB 1.05.0 Win64 (getsource.bas) Sub Proc() Print __Function__ & " is defined in " & __Path__ & "\" & __File__ & " at line " & ( __line__ - 1) End Sub Proc() Sleep
http://rosettacode.org/wiki/Reflection/Get_source	Reflection/Get source	Task The goal is to get the source code or file path and line number where a programming object (e.g. module, class, function, method) is defined.	#Go	Go	package main import ( "fmt" "path" "reflect" "runtime" ) func someFunc() { fmt.Println("someFunc called") } func main() { pc := reflect.ValueOf(someFunc).Pointer() f := runtime.FuncForPC(pc) name := f.Name() file, line := f.FileLine(pc) fmt.Println("Name of function :", name) fmt.Println("Name of file :", path.Base(file)) fmt.Println("Line number :", line) }
http://rosettacode.org/wiki/Reflection/Get_source	Reflection/Get source	Task The goal is to get the source code or file path and line number where a programming object (e.g. module, class, function, method) is defined.	#J	J	mean=:+/ %# 5!:5 <'mean' +/ % # 5!:6 <'mean' (+/) % # 4!:4 <'mean' _1 4!:4 <'names' 2 2 { 4!:3 '' ┌────────────────────────────────────────────┐ │/Applications/j64-804/system/main/stdlib.ijs│ └────────────────────────────────────────────┘
http://rosettacode.org/wiki/Regular_expressions	Regular expressions	Task match a string against a regular expression substitute part of a string using a regular expression	#Argile	Argile	use std, regex (: matching :) if "some matchable string" =~ /^some" "+[a-z]*" "+string$/ echo string matches else echo string "doesn't" match (: replacing :) let t = strdup "some allocated string" t =~ s/a/"4"/g t =~ s/e/"3"/g t =~ s/i/"1"/g t =~ s/o/"0"/g t =~ s/s/$/g print t free t (: flushing regex allocations :) uninit regex check mem leak; use dbg (:optional:)
http://rosettacode.org/wiki/Regular_expressions	Regular expressions	Task match a string against a regular expression substitute part of a string using a regular expression	#Arturo	Arturo	s: "This is a string" if contains? s {/string$/} -> print "yes, it ends with 'string'" replace 's {/[as]/} "x" print s
http://rosettacode.org/wiki/Reverse_a_string	Reverse a string	Task Take a string and reverse it. For example, "asdf" becomes "fdsa". Extra credit Preserve Unicode combining characters. For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa". Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#ActionScript	ActionScript	function reverseString(string:String):String { var reversed:String = new String(); for(var i:int = string.length -1; i >= 0; i--) reversed += string.charAt(i); return reversed; } function reverseStringCQAlternative(string:String):String { return string.split('').reverse().join(''); }
http://rosettacode.org/wiki/Rendezvous	Rendezvous	Demonstrate the “rendezvous” communications technique by implementing a printer monitor.	#Julia	Julia	mutable struct Printer inputpath::Channel{String} errorpath::Channel{String} inkremaining::Int32 reserve::Printer name::String function Printer(ch1, ch2, ink, name) this = new() this.inputpath = ch1 this.errorpath = ch2 this.inkremaining = ink this.name = name this.reserve = this this end end function lineprintertask(printer) while true line = take!(printer.inputpath) linesprinted = 0 if(printer.inkremaining < 1) if(printer.reserve == printer) put!(printer.errorpath, "Error: printer $(printer.name) out of ink") else put!(printer.reserve.inputpath, line) end else println(line) printer.inkremaining -= 1 end end end function schedulework(poems) printerclose(printer) = (close(printer.inputpath); close(printer.errorpath)) reserveprinter = Printer(Channel{String}(1), Channel{String}(10), 5, "Reserve") mainprinter = Printer(Channel{String}(1), Channel{String}(10), 5, "Main") mainprinter.reserve = reserveprinter @async(lineprintertask(mainprinter)) @async(lineprintertask(reserveprinter)) printers = [mainprinter, reserveprinter] activeprinter = 1 @sync( for poem in poems activeprinter = (activeprinter % length(printers)) + 1 @async( for line in poem put!(printers[activeprinter].inputpath, line) end) end) for p in printers while isready(p.errorpath) println(take!(p.errorpath)) end printerclose(p) end end const humptydumpty = ["Humpty Dumpty sat on a wall.", "Humpty Dumpty had a great fall.", "All the king's horses and all the king's men,", "Couldn't put Humpty together again."] const oldmothergoose = ["Old Mother Goose,", "When she wanted to wander,", "Would ride through the air,", "On a very fine gander.", "Jack's mother came in,", "And caught the goose soon,", "And mounting its back,", "Flew up to the moon."] schedulework([humptydumpty, oldmothergoose])
http://rosettacode.org/wiki/Rendezvous	Rendezvous	Demonstrate the “rendezvous” communications technique by implementing a printer monitor.	#Nim	Nim	import asyncdispatch, options, strutils type Printer = ref object inkLevel, id: int backup: Option[Printer] OutOfInkException = object of IOError proc print(p: Printer, line: string){.async.} = if p.inkLevel <= 0: if p.backup.isNone(): raise newException(OutOfInkException, "out of ink") else: await p.backup.get().print(line) else: p.inkLevel-=1 stdout.writeLine("$1:$2".format(p.id, line)) await sleepAsync(100) proc newPrinter(inkLevel, id: int, backup: Option[Printer]): Printer = new(result) result.inkLevel = inkLevel result.id = id result.backup = backup proc print(p: Printer, msg: seq[string]){.async.} = for line in msg: try: await p.print(line) except OutOfInkException as e: echo("out of ink") break const humptyLines = @[ "Humpty Dumpty sat on a wall.", "Humpty Dumpty had a great fall.", "All the king's horses and all the king's men,", "Couldn't put Humpty together again.", ] gooseLines = @[ "Old Mother Goose,", "When she wanted to wander,", "Would ride through the air,", "On a very fine gander.", "Jack's mother came in,", "And caught the goose soon,", "And mounting its back,", "Flew up to the moon.", ] proc main(){.async.} = var reservePrinter = newPrinter(5, 2, none(Printer)) mainPrinter = newPrinter(5, 1, some(reservePrinter)) await mainPrinter.print(gooseLines) and mainPrinter.print(humptyLines) waitFor main()
http://rosettacode.org/wiki/Rendezvous	Rendezvous	Demonstrate the “rendezvous” communications technique by implementing a printer monitor.	#Oz	Oz	declare class Printer attr ink:5 feat id backup meth init(id:ID backup:Backup<=unit) self.id = ID self.backup = Backup end meth print(Line)=Msg if @ink == 0 then if self.backup == unit then raise outOfInk end else {self.backup Msg} end else {System.printInfo self.id#": "} for C in Line do {System.printInfo [C]} end {System.printInfo "\n"} ink := @ink - 1 end end end
http://rosettacode.org/wiki/Repeat	Repeat	Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.	#C.23	C#	using System; namespace Repeat { class Program { static void Repeat(int count, Action<int> fn) { if (null == fn) { throw new ArgumentNullException("fn"); } for (int i = 0; i < count; i++) { fn.Invoke(i + 1); } } static void Main(string[] args) { Repeat(3, x => Console.WriteLine("Example {0}", x)); } } }
http://rosettacode.org/wiki/Repeat	Repeat	Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.	#C.2B.2B	C++	template <typename Function> void repeat(Function f, unsigned int n) { for(unsigned int i=n; 0<i; i--) f(); }
http://rosettacode.org/wiki/Rename_a_file	Rename a file	Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)	#BBC_BASIC	BBC BASIC	RENAME input.txt output.txt RENAME \input.txt \output.txt RENAME docs. mydocs. RENAME \docs. \mydocs.
http://rosettacode.org/wiki/Rename_a_file	Rename a file	Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)	#Bracmat	Bracmat	ren$("input.txt"."output.txt") { 'ren' is based on standard C function 'rename()' } ren$(docs.mydocs) { No quotes needed: names don't contain dots or colons. } ren$("d:\\input.txt"."d:\\output.txt") { Backslash is escape character, so we need to escape it. } ren$(@"d:\docs".@"d:\mydocs") { @ used as syntactic sugar as in C# for inhibiting escape. }
http://rosettacode.org/wiki/Resistor_mesh	Resistor mesh	Task Given 10×10 grid nodes (as shown in the image) interconnected by 1Ω resistors as shown, find the resistance between points A and B. See also (humor, nerd sniping) xkcd.com cartoon	#Perl	Perl	use strict; use warnings; my ($w, $h) = (9, 9); my @v = map([ (0) x ($w + 1) ], 0 .. $h); # voltage my @f = map([ (0) x ($w + 1) ], 0 .. $h); # fixed condition my @d = map([ (0) x ($w + 1) ], 0 .. $h); # diff my @n; # neighbors for my $i (0 .. $h) { push @{$n[$i][$_]}, [$i, $_ - 1] for 1 .. $w; push @{$n[$i][$_]}, [$i, $_ + 1] for 0 .. $w - 1; } for my $j (0 .. $w) { push @{$n[$_][$j]}, [$_ - 1, $j] for 1 .. $h; push @{$n[$_][$j]}, [$_ + 1, $j] for 0 .. $h - 1; } sub set_boundary { $f[1][1] = 1; $f[6][7] = -1; $v[1][1] = 1; $v[6][7] = -1; } sub calc_diff { my $total_diff; for my $i (0 .. $h) { for my $j (0 .. $w) { my ($p, $v) = $n[$i][$j]; $v += $v[$_->[0]][$_->[1]] for @$p; $d[$i][$j] = $v = $v[$i][$j] - $v / scalar(@$p); $total_diff += $v * $v unless $f[$i][$j]; } } $total_diff; } sub iter { my $diff = 1; while ($diff > 1e-15) { set_boundary(); $diff = calc_diff(); #print "error^2: $diff\n"; # un-comment to see slow convergence for my $i (0 .. $h) { for my $j (0 .. $w) { $v[$i][$j] -= $d[$i][$j]; } } } my @current = (0) x 3; for my $i (0 .. $h) { for my $j (0 .. $w) { $current[ $f[$i][$j] ] += $d[$i][$j] * scalar(@{$n[$i][$j]}); } } return ($current[1] - $current[-1]) / 2; } printf "R = %.6f\n", 2 / iter();
http://rosettacode.org/wiki/Respond_to_an_unknown_method_call	Respond to an unknown method call	Task Demonstrate how to make the object respond (sensibly/usefully) to an invocation of a method on it that it does not support through its class definitions. Note that this is not the same as just invoking a defined method whose name is given dynamically; the method named at the point of invocation must not be defined. This task is intended only for object systems that use a dynamic dispatch mechanism without static checking. Related task Send an unknown method call.	#Wren	Wren	import "io" for Stdin, Stdout class Test { construct new() {} foo() { System.print("Foo called.") } bar() { System.print("Bar called.") } missingMethod(m) { System.print(m) System.write("Try and continue anyway y/n ? ") Stdout.flush() var reply = Stdin.readLine() if (reply != "y" && reply != "Y") { Fiber.abort("Decided to abort due to missing method.") } } } var test = Test.new() var f = Fiber.new { test.foo() test.bar() test.baz() } f.try() var err = f.error if (err) { if (err.startsWith("Test does not implement")) { test.missingMethod(err) } else { Fiber.abort(err) // rethrow other errors } } System.print("OK, continuing.")
http://rosettacode.org/wiki/Respond_to_an_unknown_method_call	Respond to an unknown method call	Task Demonstrate how to make the object respond (sensibly/usefully) to an invocation of a method on it that it does not support through its class definitions. Note that this is not the same as just invoking a defined method whose name is given dynamically; the method named at the point of invocation must not be defined. This task is intended only for object systems that use a dynamic dispatch mechanism without static checking. Related task Send an unknown method call.	#zkl	zkl	class C{ fcn __notFound(name){println(name," not in ",self); bar} fcn bar{vm.arglist.println("***")} }
http://rosettacode.org/wiki/Reverse_words_in_a_string	Reverse words in a string	Task Reverse the order of all tokens in each of a number of strings and display the result; the order of characters within a token should not be modified. Example Hey you, Bub! would be shown reversed as: Bub! you, Hey Tokens are any non-space characters separated by spaces (formally, white-space); the visible punctuation form part of the word within which it is located and should not be modified. You may assume that there are no significant non-visible characters in the input. Multiple or superfluous spaces may be compressed into a single space. Some strings have no tokens, so an empty string (or one just containing spaces) would be the result. Display the strings in order (1st, 2nd, 3rd, ···), and one string per line. (You can consider the ten strings as ten lines, and the tokens as words.) Input data (ten lines within the box) line ╔════════════════════════════════════════╗ 1 ║ ---------- Ice and Fire ------------ ║ 2 ║ ║ ◄─── a blank line here. 3 ║ fire, in end will world the say Some ║ 4 ║ ice. in say Some ║ 5 ║ desire of tasted I've what From ║ 6 ║ fire. favor who those with hold I ║ 7 ║ ║ ◄─── a blank line here. 8 ║ ... elided paragraph last ... ║ 9 ║ ║ ◄─── a blank line here. 10 ║ Frost Robert ----------------------- ║ ╚════════════════════════════════════════╝ Cf. Phrase reversals	#D	D	void main() { import std.stdio, std.string, std.range, std.algorithm; immutable text = "---------- Ice and Fire ------------ fire, in end will world the say Some ice. in say Some desire of tasted I've what From fire. favor who those with hold I ... elided paragraph last ... Frost Robert -----------------------"; writefln("%(%-(%s %)\n%)", text.splitLines.map!(r => r.split.retro)); }
http://rosettacode.org/wiki/Rot-13	Rot-13	Task Implement a rot-13 function (or procedure, class, subroutine, or other "callable" object as appropriate to your programming environment). Optionally wrap this function in a utility program (like tr, which acts like a common UNIX utility, performing a line-by-line rot-13 encoding of every line of input contained in each file listed on its command line, or (if no filenames are passed thereon) acting as a filter on its "standard input." (A number of UNIX scripting languages and utilities, such as awk and sed either default to processing files in this way or have command line switches or modules to easily implement these wrapper semantics, e.g., Perl and Python). The rot-13 encoding is commonly known from the early days of Usenet "Netnews" as a way of obfuscating text to prevent casual reading of spoiler or potentially offensive material. Many news reader and mail user agent programs have built-in rot-13 encoder/decoders or have the ability to feed a message through any external utility script for performing this (or other) actions. The definition of the rot-13 function is to simply replace every letter of the ASCII alphabet with the letter which is "rotated" 13 characters "around" the 26 letter alphabet from its normal cardinal position (wrapping around from z to a as necessary). Thus the letters abc become nop and so on. Technically rot-13 is a "mono-alphabetic substitution cipher" with a trivial "key". A proper implementation should work on upper and lower case letters, preserve case, and pass all non-alphabetic characters in the input stream through without alteration. Related tasks Caesar cipher Substitution Cipher Vigenère Cipher/Cryptanalysis Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#PicoLisp	PicoLisp	(de rot13-Ch (C) (if (or (member C '`(apply circ (chop "ABCDEFGHIJKLMNOPQRSTUVWXYZ"))) (member C '`(apply circ (chop "abcdefghijklmnopqrstuvwxyz"))) ) (get @ 14) C ) )
http://rosettacode.org/wiki/Roman_numerals/Encode	Roman numerals/Encode	Task Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero. In Roman numerals: 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC 2008 is written as 2000=MM, 8=VIII; or MMVIII 1666 uses each Roman symbol in descending order: MDCLXVI	#Pascal	Pascal	<@ DEFUDOLITLIT>_RO\|__Transformer\|<@ DEFKEYPAR>__NationalNumericID\|2</@><@ LETRESCS%NNMPAR>...\|1</@></@> <@ ENU$$DLSTLITLIT>1990,2008,1,2,64,124,1666,10001\|,\| <@ SAYELTLST>...</@> is <@ SAY_ROELTLSTLIT>...\|RomanLowerUnicode</@> <@ SAY_ROELTLSTLIT>...\|RomanUpperUnicode</@> <@ SAY_ROELTLSTLIT>...\|RomanASCII</@> </@>
http://rosettacode.org/wiki/Roman_numerals/Decode	Roman numerals/Decode	Task Create a function that takes a Roman numeral as its argument and returns its value as a numeric decimal integer. You don't need to validate the form of the Roman numeral. Modern Roman numerals are written by expressing each decimal digit of the number to be encoded separately, starting with the leftmost decimal digit and skipping any 0s (zeroes). 1990 is rendered as MCMXC (1000 = M, 900 = CM, 90 = XC) and 2008 is rendered as MMVIII (2000 = MM, 8 = VIII). The Roman numeral for 1666, MDCLXVI, uses each letter in descending order.	#QB64	QB64	SCREEN _NEWIMAGE(400, 600, 32) CLS Main: '------------------------------------------------ ' CALLS THE romToDec FUNCTION WITH THE ROMAN ' NUMERALS AND RETURNS ITS DECIMAL EQUIVELENT. ' PRINT "ROMAN NUMERAL TO DECIMAL CONVERSION" PRINT: PRINT PRINT "MDCCIV = "; romToDec("MDCCIV") '1704 PRINT "MCMXC = "; romToDec("MCMXC") '1990 PRINT "MMVIII = "; romToDec("MMVIII") '2008 PRINT "MDCLXVI = "; romToDec("MDCLXVI") '1666 PRINT: PRINT PRINT "Here are other solutions not from the TASK:" PRINT "MCMXCIX = "; romToDec("MCMXCIX") '1999 PRINT "XXV = "; romToDec("XXV") '25 PRINT "CMLIV = "; romToDec("CMLIV") '954 PRINT "MMXI = "; romToDec("MMXI") '2011 PRINT "MMIIIX = "; romToDec("MMIIIX") '2011 PRINT: PRINT PRINT "2011 can be written either as MMXI or MMIIIX" PRINT "With the IX = 9, MMIIIX is also 2011." PRINT "2011 IS CORRECT (MM=2000 + II = 2 + IX = 9)" END FUNCTION romToDec (roman AS STRING) '------------------------------------------------------ ' FUNCTION THAT CONVERTS ANY ROMAN NUMERAL TO A DECIMAL ' prenum = 0: num = 0 LN = LEN(roman) FOR i = LN TO 1 STEP -1 x$ = MID$(roman, i, 1) n = 1000 SELECT CASE x$ CASE "M": n = n / 1 CASE "D": n = n / 2 CASE "C": n = n / 10 CASE "L": n = n / 20 CASE "X": n = n / 100 CASE "V": n = n / 200 CASE "I": n = n / n CASE ELSE: n = 0 END SELECT IF n < prenum THEN num = num - n ELSE num = num + n prenum = n NEXT i romToDec = num END FUNCTION
http://rosettacode.org/wiki/Run-length_encoding	Run-length encoding	Run-length encoding You are encouraged to solve this task according to the task description, using any language you may know. Task Given a string containing uppercase characters (A-Z), compress repeated 'runs' of the same character by storing the length of that run, and provide a function to reverse the compression. The output can be anything, as long as you can recreate the input with it. Example Input: WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW Output: 12W1B12W3B24W1B14W Note: the encoding step in the above example is the same as a step of the Look-and-say sequence.	#zkl	zkl	const MAX_LEN=250, MIN_LEN=3; fcn compress(text){ // !empty byte/text stream -->Data (byte stream) sink:=Data(); cnt:=Ref(0); write:='wrap(c,n){ // helper function while(n>MAX_LEN){ sink.write(1); sink.write(MAX_LEN); sink.write(c); n-=MAX_LEN; } if(n>MIN_LEN){ sink.write(1); sink.write(n); sink.write(c); } else { do(n) { sink.write(c); } } }; text.reduce('wrap(a,b){ if(a==b) cnt.inc(); else{ write(a,cnt.value); cnt.set(1); } b },text[0]) : write(_,cnt.value); sink; }
http://rosettacode.org/wiki/Repeat_a_string	Repeat a string	Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("", 5) => "****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet	#AWK	AWK	function repeat( str, n, rep, i ) { for( ; i<n; i++ ) rep = rep str return rep } BEGIN { print repeat( "ha", 5 ) }
http://rosettacode.org/wiki/Return_multiple_values	Return multiple values	Task Show how to return more than one value from a function.	#D	D	import std.stdio, std.typecons, std.algorithm; mixin template ret(string z) { mixin({ string res; auto r = z.split(" = "); auto m = r[0].split(", "); auto s = m.join("_"); res ~= "auto " ~ s ~ " = " ~ r[1] ~ ";"; foreach(i, n; m){ res ~= "auto " ~ n ~ " = " ~ s ~ "[" ~ i.to!string ~ "];\n"; } return res; }()); } auto addSub(T)(T x, T y) { return tuple(x + y, x - y); } void main() { mixin ret!q{ a, b = addSub(33, 12) }; writefln("33 + 12 = %d\n33 - 12 = %d", a, b); }

http://rosettacode.org/wiki/Rot-13

Rot-13

Task Implement a rot-13 function (or procedure, class, subroutine, or other "callable" object as appropriate to your programming environment). Optionally wrap this function in a utility program (like tr, which acts like a common UNIX utility, performing a line-by-line rot-13 encoding of every line of input contained in each file listed on its command line, or (if no filenames are passed thereon) acting as a filter on its "standard input." (A number of UNIX scripting languages and utilities, such as awk and sed either default to processing files in this way or have command line switches or modules to easily implement these wrapper semantics, e.g., Perl and Python). The rot-13 encoding is commonly known from the early days of Usenet "Netnews" as a way of obfuscating text to prevent casual reading of spoiler or potentially offensive material. Many news reader and mail user agent programs have built-in rot-13 encoder/decoders or have the ability to feed a message through any external utility script for performing this (or other) actions. The definition of the rot-13 function is to simply replace every letter of the ASCII alphabet with the letter which is "rotated" 13 characters "around" the 26 letter alphabet from its normal cardinal position (wrapping around from z to a as necessary). Thus the letters abc become nop and so on. Technically rot-13 is a "mono-alphabetic substitution cipher" with a trivial "key". A proper implementation should work on upper and lower case letters, preserve case, and pass all non-alphabetic characters in the input stream through without alteration. Related tasks Caesar cipher Substitution Cipher Vigenère Cipher/Cryptanalysis Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#Perl

Perl

sub rot13 { shift =~ tr/A-Za-z/N-ZA-Mn-za-m/r; } print rot13($_) while (<>);

http://rosettacode.org/wiki/Roman_numerals/Encode

Roman numerals/Encode

Task Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero. In Roman numerals: 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC 2008 is written as 2000=MM, 8=VIII; or MMVIII 1666 uses each Roman symbol in descending order: MDCLXVI

#Oforth

Oforth

[ [1000,"M"], [900,"CM"], [500,"D"], [400,"CD"], [100,"C"], [90,"XC"], [50,"L"], [40,"XL"], [10,"X"], [9,"IX"], [5,"V"], [4,"IV"], [1,"I"] ] const: Romans : roman(n) | r | StringBuffer new Romans forEach: r [ while(r first n <=) [ r second << n r first - ->n ] ] ;

http://rosettacode.org/wiki/Roman_numerals/Decode

Roman numerals/Decode

Task Create a function that takes a Roman numeral as its argument and returns its value as a numeric decimal integer. You don't need to validate the form of the Roman numeral. Modern Roman numerals are written by expressing each decimal digit of the number to be encoded separately, starting with the leftmost decimal digit and skipping any 0s (zeroes). 1990 is rendered as MCMXC (1000 = M, 900 = CM, 90 = XC) and 2008 is rendered as MMVIII (2000 = MM, 8 = VIII). The Roman numeral for 1666, MDCLXVI, uses each letter in descending order.

#PureBasic

PureBasic

Procedure romanDec(roman.s) Protected i, n, lastval, arabic For i = Len(roman) To 1 Step -1 Select UCase(Mid(roman, i, 1)) Case "M" n = 1000 Case "D" n = 500 Case "C" n = 100 Case "L" n = 50 Case "X" n = 10 Case "V" n = 5 Case "I" n = 1 Default n = 0 EndSelect If (n < lastval) arabic - n Else arabic + n EndIf lastval = n Next ProcedureReturn arabic EndProcedure If OpenConsole() PrintN(Str(romanDec("MCMXCIX"))) ;1999 PrintN(Str(romanDec("MDCLXVI"))) ;1666 PrintN(Str(romanDec("XXV"))) ;25 PrintN(Str(romanDec("CMLIV"))) ;954 PrintN(Str(romanDec("MMXI"))) ;2011 Print(#CRLF$ + #CRLF$ + "Press ENTER to exit"): Input() CloseConsole() EndIf

http://rosettacode.org/wiki/Run-length_encoding

Run-length encoding

Run-length encoding You are encouraged to solve this task according to the task description, using any language you may know. Task Given a string containing uppercase characters (A-Z), compress repeated 'runs' of the same character by storing the length of that run, and provide a function to reverse the compression. The output can be anything, as long as you can recreate the input with it. Example Input: WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW Output: 12W1B12W3B24W1B14W Note: the encoding step in the above example is the same as a step of the Look-and-say sequence.

#VBA

VBA

Option Explicit Sub Main() Dim p As String p = length_encoding("WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW") Debug.Print p Debug.Print length_decoding(p) End Sub Private Function length_encoding(S As String) As String Dim F As String, r As String, a As String, n As Long, c As Long, k As Long r = Left(S, 1) c = 1 For n = 2 To Len(S) If r <> Mid(S, n, 1) Then a = a & c & r r = Mid(S, n, 1) c = 1 Else c = c + 1 End If Next length_encoding = a & c & r End Function Private Function length_decoding(S As String) As String Dim F As Long, r As String, a As String For F = 1 To Len(S) If IsNumeric(Mid(S, F, 1)) Then r = r & Mid(S, F, 1) Else a = a & String(CLng(r), Mid(S, F, 1)) r = vbNullString End If Next length_decoding = a End Function

http://rosettacode.org/wiki/Repeat_a_string

Repeat a string

Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("*", 5) => "*****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#AppleScript

AppleScript

set str to "ha" set final_string to "" repeat 5 times set final_string to final_string & str end repeat

http://rosettacode.org/wiki/Return_multiple_values

Return multiple values

Task Show how to return more than one value from a function.

#Clojure

Clojure

(defn quot-rem [m n] [(quot m n) (rem m n)]) ; The following prints 3 2. (let [[q r] (quot-rem 11 3)] (println q) (println r))

http://rosettacode.org/wiki/Rep-string

Rep-string

Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#Ada

Ada

with Ada.Command_Line, Ada.Text_IO, Ada.Strings.Fixed; procedure Rep_String is function Find_Largest_Rep_String(S:String) return String is L: Natural := S'Length; begin for I in reverse 1 .. L/2 loop declare use Ada.Strings.Fixed; T: String := S(S'First .. S'First + I-1); -- the first I characters of S U: String := (1+(L/I)) * T; -- repeat T so often that U'Length >= L begin -- compare first L characers of U with S if U(U'First .. U'First + S'Length -1) = S then return T; -- T is a rep-string end if; end; end loop; return ""; -- no rep string; end Find_Largest_Rep_String; X: String := Ada.Command_Line.Argument(1); Y: String := Find_Largest_Rep_String(X); begin if Y="" then Ada.Text_IO.Put_Line("No rep-string for """ & X & """"); else Ada.Text_IO.Put_Line("Longest rep-string for """& X &""": """& Y &""""); end if; end Rep_String;

http://rosettacode.org/wiki/Regular_expressions

Regular expressions

Task match a string against a regular expression substitute part of a string using a regular expression

#Ada

Ada

with Ada.Text_IO; with Gnat.Regpat; use Ada.Text_IO; procedure Regex is package Pat renames Gnat.Regpat; procedure Search_For_Pattern(Compiled_Expression: Pat.Pattern_Matcher; Search_In: String; First, Last: out Positive; Found: out Boolean) is Result: Pat.Match_Array (0 .. 1); begin Pat.Match(Compiled_Expression, Search_In, Result); Found := not Pat."="(Result(1), Pat.No_Match); if Found then First := Result(1).First; Last := Result(1).Last; end if; end Search_For_Pattern; Word_Pattern: constant String := "([a-zA-Z]+)"; Str: String:= "I love PATTERN matching!"; Current_First: Positive := Str'First; First, Last: Positive; Found: Boolean; begin -- first, find all the words in Str loop Search_For_Pattern(Pat.Compile(Word_Pattern), Str(Current_First .. Str'Last), First, Last, Found); exit when not Found; Put_Line("<" & Str(First .. Last) & ">"); Current_First := Last+1; end loop; -- second, replace "PATTERN" in Str by "pattern" Search_For_Pattern(Pat.Compile("(PATTERN)"), Str, First, Last, Found); Str := Str(Str'First .. First-1) & "pattern" & Str(Last+1 .. Str'Last); Put_Line(Str); end Regex;

http://rosettacode.org/wiki/Reverse_a_string

Reverse a string

Task Take a string and reverse it. For example, "asdf" becomes "fdsa". Extra credit Preserve Unicode combining characters. For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa". Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#8th

8th

"abc" s:rev

http://rosettacode.org/wiki/Rendezvous

Rendezvous

Demonstrate the “rendezvous” communications technique by implementing a printer monitor.

#Erlang

Erlang

-module( rendezvous ). -export( [task/0] ). task() -> Printer_pid = erlang:spawn( fun() -> printer(1, 5) end ), Reserve_printer_pid = erlang:spawn( fun() -> printer(2, 5) end ), Monitor_pid = erlang:spawn( fun() -> printer_monitor(Printer_pid, Reserve_printer_pid) end ), erlang:spawn( fun() -> print(Monitor_pid, humpty_dumpty()) end ), erlang:spawn( fun() -> print(Monitor_pid, mother_goose()) end ). humpty_dumpty() -> ["Humpty Dumpty sat on a wall.", "Humpty Dumpty had a great fall.", "All the king's horses and all the king's men,", "Couldn't put Humpty together again."]. mother_goose() -> ["Old Mother Goose,", "When she wanted to wander,", "Would ride through the air,", "On a very fine gander.", "Jack's mother came in,", "And caught the goose soon,", "And mounting its back,", "Flew up to the moon."]. print( Pid, Lines ) -> io:fwrite( "Print ~p started~n", [erlang:self()] ), print( Pid, Lines, infinity ). print( _Pid, [], _Timeout ) -> ok; print( Pid, [Line | T], Timeout ) -> print_line( Pid, Line, Timeout ), print_line_done(), print( Pid, T, Timeout ). print_line( Pid, Line, Timeout ) -> Pid ! {print, Line, erlang:self()}, receive {print, started} -> ok after Timeout -> erlang:throw( timeout ) end. print_line_done() -> receive {printer, ok} -> ok; {printer, out_of_ink} -> erlang:throw( out_of_ink ) end. printer( N, 0 ) -> receive {print, _Line, Pid} -> Pid ! {printer, out_of_ink} end, printer( N, 0 ); printer( N, Ink ) -> receive {print, Line, Pid} -> Pid ! {printer, ok}, io:fwrite( "~p: ", [N] ), [io:fwrite("~c", [X]) || X <- Line], io:nl() end, printer( N, Ink - 1 ). printer_monitor( Printer, Reserve ) -> {Line, Pid} = printer_monitor_get_line(), Result = printer_monitor_print_line( Printer, Line ), printer_monitor_reserve( Result, Reserve, Line, Pid ), printer_monitor( Printer, Reserve ). printer_monitor_get_line() -> receive {print, Line, Pid} -> Pid ! {print, started}, {Line, Pid} end. printer_monitor_print_line( Printer_pid, Line ) -> Printer_pid ! {print, Line, erlang:self()}, receive {printer, Result} -> Result end. printer_monitor_reserve( ok, _Reserve_pid, _Line, Pid ) -> Pid ! {printer, ok}; printer_monitor_reserve( out_of_ink, Reserve_pid, Line, Pid ) -> Reserve_pid ! {print, Line, Pid}.

http://rosettacode.org/wiki/Repeat

Repeat

Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.

#AutoHotkey

AutoHotkey

repeat("fMsgBox",3) return repeat(f, n){ loop % n %f%() } fMsgBox(){ MsgBox hello }

http://rosettacode.org/wiki/Rename_a_file

Rename a file

Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)

#AutoHotkey

AutoHotkey

FileMove, oldname, newname

http://rosettacode.org/wiki/Rename_a_file

Rename a file

Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)

#AutoIt

AutoIt

$ awk 'BEGIN{system("mv input.txt output.txt")}' $ awk 'BEGIN{system("mv docs mydocs")}' $ awk 'BEGIN{system("mv /input.txt /output.txt")}' $ awk 'BEGIN{system("mv docs mydocs")}'

http://rosettacode.org/wiki/RIPEMD-160

RIPEMD-160

RIPEMD-160 is another hash function; it computes a 160-bit message digest. There is a RIPEMD-160 home page, with test vectors and pseudocode for RIPEMD-160. For padding the message, RIPEMD-160 acts like MD4 (RFC 1320). Find the RIPEMD-160 message digest of a string of octets. Use the ASCII encoded string “Rosetta Code”. You may either call an RIPEMD-160 library, or implement RIPEMD-160 in your language.

#Tcl

Tcl

package require ripemd160 puts [ripemd::ripemd160 -hex "Rosetta Code"]

http://rosettacode.org/wiki/RIPEMD-160

RIPEMD-160

RIPEMD-160 is another hash function; it computes a 160-bit message digest. There is a RIPEMD-160 home page, with test vectors and pseudocode for RIPEMD-160. For padding the message, RIPEMD-160 acts like MD4 (RFC 1320). Find the RIPEMD-160 message digest of a string of octets. Use the ASCII encoded string “Rosetta Code”. You may either call an RIPEMD-160 library, or implement RIPEMD-160 in your language.

#Wren

Wren

import "/crypto" for Ripemd160 import "/fmt" for Fmt var strings = [ "", "a", "abc", "message digest", "abcdefghijklmnopqrstuvwxyz", "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789", "12345678901234567890123456789012345678901234567890123456789012345678901234567890", "The quick brown fox jumps over the lazy dog", "The quick brown fox jumps over the lazy cog", "Rosetta Code" ] for (s in strings) { var hash = Ripemd160.digest(s) Fmt.print("$s <== '$0s'", hash, s) }

http://rosettacode.org/wiki/Resistor_mesh

Resistor mesh

Task Given 10×10 grid nodes (as shown in the image) interconnected by 1Ω resistors as shown, find the resistance between points A and B. See also (humor, nerd sniping) xkcd.com cartoon

#Modula-2

Modula-2

MODULE ResistorMesh; FROM RConversions IMPORT RealToStringFixed; FROM Terminal IMPORT WriteString,WriteLn,ReadChar; CONST S = 10; TYPE Node = RECORD v : LONGREAL; fixed : INTEGER; END; PROCEDURE SetBoundary(VAR m : ARRAY OF ARRAY OF Node); BEGIN m[1][1].v := 1.0; m[1][1].fixed := 1; m[6][7].v := -1.0; m[6][7].fixed := -1; END SetBoundary; PROCEDURE CalcDiff(VAR m,d : ARRAY OF ARRAY OF Node) : LONGREAL; VAR total,v : LONGREAL; i,j,n : INTEGER; BEGIN total := 0.0; FOR i:=0 TO S DO FOR j:=0 TO S DO v := 0.0; n := 0; IF i>0 THEN v := v + m[i-1][j].v; INC(n); END; IF j>0 THEN v := v + m[i][j-1].v; INC(n); END; IF i+1<S THEN v := v + m[i+1][j].v; INC(n); END; IF j+1<S THEN v := v + m[i][j+1].v; INC(n); END; v := m[i][j].v - v / LFLOAT(n); d[i][j].v := v; IF m[i][j].fixed=0 THEN total := total + v*v; END; END; END; RETURN total; END CalcDiff; PROCEDURE Iter(m : ARRAY OF ARRAY OF Node) : LONGREAL; VAR d : ARRAY[0..S] OF ARRAY[0..S] OF Node; i,j,k : INTEGER; cur : ARRAY[0..2] OF LONGREAL; diff : LONGREAL; BEGIN FOR i:=0 TO S DO FOR j:=0 TO S DO d[i][j] := Node{0.0,0}; END; END; diff := 1.0E10; WHILE diff>1.0E-24 DO SetBoundary(m); diff := CalcDiff(m,d); FOR i:=0 TO S DO FOR j:=0 TO S DO m[i][j].v := m[i][j].v - d[i][j].v; END; END; END; FOR i:=0 TO S DO FOR j:=0 TO S DO k:=0; IF i#0 THEN INC(k) END; IF j#0 THEN INC(k) END; IF i<S-1 THEN INC(k) END; IF j<S-1 THEN INC(k) END; cur[m[i][j].fixed+1] := cur[m[i][j].fixed+1] + d[i][j].v*LFLOAT(k); END; END; RETURN (cur[2]-cur[0]) / 2.0; END Iter; VAR mesh : ARRAY[0..S] OF ARRAY[0..S] OF Node; buf : ARRAY[0..32] OF CHAR; r : LONGREAL; pos : CARDINAL; ok : BOOLEAN; BEGIN pos := 0; r := 2.0 / Iter(mesh); WriteString("R = "); RealToStringFixed(r, 15,0, buf, pos, ok); WriteString(buf); WriteString(" ohms"); WriteLn; ReadChar; END ResistorMesh.

http://rosettacode.org/wiki/Respond_to_an_unknown_method_call

Respond to an unknown method call

Task Demonstrate how to make the object respond (sensibly/usefully) to an invocation of a method on it that it does not support through its class definitions. Note that this is not the same as just invoking a defined method whose name is given dynamically; the method named at the point of invocation must not be defined. This task is intended only for object systems that use a dynamic dispatch mechanism without static checking. Related task Send an unknown method call.

#Scala

Scala

class DynamicTest extends Dynamic { def foo()=println("this is foo") def bar()=println("this is bar") def applyDynamic(name: String)(args: Any*)={ println("tried to handle unknown method "+name) if(!args.isEmpty) println(" it had arguments: "+args.mkString(",")) } } object DynamicTest { def main(args: Array[String]): Unit = { val d=new DynamicTest() d.foo() d.bar() d.grill() d.ding("dong") } }

http://rosettacode.org/wiki/Respond_to_an_unknown_method_call

Respond to an unknown method call

Task Demonstrate how to make the object respond (sensibly/usefully) to an invocation of a method on it that it does not support through its class definitions. Note that this is not the same as just invoking a defined method whose name is given dynamically; the method named at the point of invocation must not be defined. This task is intended only for object systems that use a dynamic dispatch mechanism without static checking. Related task Send an unknown method call.

#Sidef

Sidef

class Example { method foo { say "this is foo" } method bar { say "this is bar" } method AUTOLOAD(_, name, *args) { say ("tried to handle unknown method %s" % name); if (args.len > 0) { say ("it had arguments: %s" % args.join(', ')); } } } var example = Example.new; example.foo; # prints “this is foo” example.bar; # prints “this is bar” example.grill; # prints “tried to handle unknown method grill” example.ding("dong"); # prints “tried to handle unknown method ding” # prints “it had arguments: dong”

http://rosettacode.org/wiki/Reverse_words_in_a_string

Reverse words in a string

Task Reverse the order of all tokens in each of a number of strings and display the result; the order of characters within a token should not be modified. Example Hey you, Bub! would be shown reversed as: Bub! you, Hey Tokens are any non-space characters separated by spaces (formally, white-space); the visible punctuation form part of the word within which it is located and should not be modified. You may assume that there are no significant non-visible characters in the input. Multiple or superfluous spaces may be compressed into a single space. Some strings have no tokens, so an empty string (or one just containing spaces) would be the result. Display the strings in order (1st, 2nd, 3rd, ···), and one string per line. (You can consider the ten strings as ten lines, and the tokens as words.) Input data (ten lines within the box) line ╔════════════════════════════════════════╗ 1 ║ ---------- Ice and Fire ------------ ║ 2 ║ ║ ◄─── a blank line here. 3 ║ fire, in end will world the say Some ║ 4 ║ ice. in say Some ║ 5 ║ desire of tasted I've what From ║ 6 ║ fire. favor who those with hold I ║ 7 ║ ║ ◄─── a blank line here. 8 ║ ... elided paragraph last ... ║ 9 ║ ║ ◄─── a blank line here. 10 ║ Frost Robert ----------------------- ║ ╚════════════════════════════════════════╝ Cf. Phrase reversals

#COBOL

COBOL

program-id. rev-word. data division. working-storage section. 1 text-block. 2 pic x(36) value "---------- Ice and Fire ------------". 2 pic x(36) value " ". 2 pic x(36) value "fire, in end will world the say Some". 2 pic x(36) value "ice. in say Some ". 2 pic x(36) value "desire of tasted I've what From ". 2 pic x(36) value "fire. favor who those with hold I ". 2 pic x(36) value " ". 2 pic x(36) value "... elided paragraph last ... ". 2 pic x(36) value " ". 2 pic x(36) value "Frost Robert -----------------------". 1 redefines text-block. 2 occurs 10. 3 text-line pic x(36). 1 text-word. 2 wk-len binary pic 9(4). 2 wk-word pic x(36). 1 word-stack. 2 occurs 10. 3 word-entry. 4 word-len binary pic 9(4). 4 word pic x(36). 1 binary. 2 i pic 9(4). 2 pos pic 9(4). 2 word-stack-ptr pic 9(4). procedure division. perform varying i from 1 by 1 until i > 10 perform push-words perform pop-words end-perform stop run . push-words. move 1 to pos move 0 to word-stack-ptr perform until pos > 36 unstring text-line (i) delimited by all space into wk-word count in wk-len pointer pos end-unstring add 1 to word-stack-ptr move text-word to word-entry (word-stack-ptr) end-perform . pop-words. perform varying word-stack-ptr from word-stack-ptr by -1 until word-stack-ptr < 1 move word-entry (word-stack-ptr) to text-word display wk-word (1:wk-len) space with no advancing end-perform display space . end program rev-word.

http://rosettacode.org/wiki/Rot-13

Rot-13

Task Implement a rot-13 function (or procedure, class, subroutine, or other "callable" object as appropriate to your programming environment). Optionally wrap this function in a utility program (like tr, which acts like a common UNIX utility, performing a line-by-line rot-13 encoding of every line of input contained in each file listed on its command line, or (if no filenames are passed thereon) acting as a filter on its "standard input." (A number of UNIX scripting languages and utilities, such as awk and sed either default to processing files in this way or have command line switches or modules to easily implement these wrapper semantics, e.g., Perl and Python). The rot-13 encoding is commonly known from the early days of Usenet "Netnews" as a way of obfuscating text to prevent casual reading of spoiler or potentially offensive material. Many news reader and mail user agent programs have built-in rot-13 encoder/decoders or have the ability to feed a message through any external utility script for performing this (or other) actions. The definition of the rot-13 function is to simply replace every letter of the ASCII alphabet with the letter which is "rotated" 13 characters "around" the 26 letter alphabet from its normal cardinal position (wrapping around from z to a as necessary). Thus the letters abc become nop and so on. Technically rot-13 is a "mono-alphabetic substitution cipher" with a trivial "key". A proper implementation should work on upper and lower case letters, preserve case, and pass all non-alphabetic characters in the input stream through without alteration. Related tasks Caesar cipher Substitution Cipher Vigenère Cipher/Cryptanalysis Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#Phix

Phix

function rot13(string s) integer ch for i=1 to length(s) do ch = upper(s[i]) if ch>='A' and ch<='Z' then s[i] += iff(ch<='M',+13,-13) end if end for return s end function ?rot13("abjurer NOWHERE.")

http://rosettacode.org/wiki/Roman_numerals/Encode

Roman numerals/Encode

Task Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero. In Roman numerals: 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC 2008 is written as 2000=MM, 8=VIII; or MMVIII 1666 uses each Roman symbol in descending order: MDCLXVI

#OpenEdge.2FProgress

OpenEdge/Progress

FUNCTION encodeRoman RETURNS CHAR ( i_i AS INT ): DEF VAR cresult AS CHAR. DEF VAR croman AS CHAR EXTENT 7 INIT [ "M", "D", "C", "L", "X", "V", "I" ]. DEF VAR idecimal AS INT EXTENT 7 INIT [ 1000, 500, 100, 50, 10, 5, 1 ]. DEF VAR ipos AS INT INIT 1. DO WHILE i_i > 0: IF i_i - idecimal[ ipos ] >= 0 THEN ASSIGN cresult = cresult + croman[ ipos ] i_i = i_i - idecimal[ ipos ] . ELSE IF ipos < EXTENT( croman ) - 1 AND i_i - ( idecimal[ ipos ] - idecimal[ ipos + 2 ] ) >= 0 THEN ASSIGN cresult = cresult + croman[ ipos + 2 ] + croman[ ipos ] i_i = i_i - ( idecimal[ ipos ] - idecimal[ ipos + 2 ] ) ipos = ipos + 1 . ELSE ipos = ipos + 1. END. RETURN cresult. END FUNCTION. /* encodeRoman */ MESSAGE 1990 encodeRoman( 1990 ) SKIP 2008 encodeRoman( 2008 ) SKIP 2000 encodeRoman( 2000 ) SKIP 1666 encodeRoman( 1666 ) SKIP VIEW-AS ALERT-BOX.

http://rosettacode.org/wiki/Roman_numerals/Decode

Roman numerals/Decode

Task Create a function that takes a Roman numeral as its argument and returns its value as a numeric decimal integer. You don't need to validate the form of the Roman numeral. Modern Roman numerals are written by expressing each decimal digit of the number to be encoded separately, starting with the leftmost decimal digit and skipping any 0s (zeroes). 1990 is rendered as MCMXC (1000 = M, 900 = CM, 90 = XC) and 2008 is rendered as MMVIII (2000 = MM, 8 = VIII). The Roman numeral for 1666, MDCLXVI, uses each letter in descending order.

#Python

Python

_rdecode = dict(zip('MDCLXVI', (1000, 500, 100, 50, 10, 5, 1))) def decode( roman ): result = 0 for r, r1 in zip(roman, roman[1:]): rd, rd1 = _rdecode[r], _rdecode[r1] result += -rd if rd < rd1 else rd return result + _rdecode[roman[-1]] if __name__ == '__main__': for r in 'MCMXC MMVIII MDCLXVI'.split(): print( r, decode(r) )

http://rosettacode.org/wiki/Run-length_encoding

Run-length encoding

Run-length encoding You are encouraged to solve this task according to the task description, using any language you may know. Task Given a string containing uppercase characters (A-Z), compress repeated 'runs' of the same character by storing the length of that run, and provide a function to reverse the compression. The output can be anything, as long as you can recreate the input with it. Example Input: WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW Output: 12W1B12W3B24W1B14W Note: the encoding step in the above example is the same as a step of the Look-and-say sequence.

#Vedit_macro_language

Vedit macro language

:RL_ENCODE: BOF While (!At_EOF) { if (At_EOL) { Line(1) Continue } // skip newlines #1 = Cur_Char // #1 = character Match("(.)\1*", REGEXP) // count run length #2 = Chars_Matched // #2 = run length if (#2 > 127) { #2 = 127 } // can be max 127 if (#2 > 1 || #1 > 127) { Del_Char(#2) Ins_Char(#2 | 128) // run length (high bit set) Ins_Char(#1) // character } else { // single ASCII char Char // skip } } Return :RL_DECODE: BOF While (!At_EOF) { #2 = Cur_Char if (#2 > 127) { // is this run length? #1 = Cur_Char(1) // #1 = character value Del_Char(2) Ins_Char(#1, COUNT, #2 & 127) } else { // single ASCII char Char } } Return

http://rosettacode.org/wiki/Repeat_a_string

Repeat a string

Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("*", 5) => "*****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#Applesoft_BASIC

Applesoft BASIC

FOR I = 1 TO 5 : S$ = S$ + "HA" : NEXT ? "X" SPC(20) "X"

http://rosettacode.org/wiki/Repeat_a_string

Repeat a string

Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("*", 5) => "*****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#Arturo

Arturo

print repeat "ha" 5

http://rosettacode.org/wiki/Return_multiple_values

Return multiple values

Task Show how to return more than one value from a function.

#CLU

CLU

% Returning multiple values (along with type parameterization) % was actually invented with CLU. % Do note that the procedure is actually returning multiple % values; it's not returning a tuple and unpacking it. % That doesn't exist in CLU. % For added CLU-ness, this function is fully general, requiring % only that its arguments support addition and subtraction in any way add_sub = proc [T,U,V,W: type] (a: T, b: U) returns (V, W) signals (overflow) where T has add: proctype (T,U) returns (V) signals (overflow), sub: proctype (T,U) returns (W) signals (overflow) return (a+b, a-b) resignal overflow end add_sub % And actually using it start_up = proc () add_sub_int = add_sub[int,int,int,int] % boring, but does what you'd expect po: stream := stream$primary_output() % returning two values from the function sum, diff: int := add_sub_int(33, 12) % print out both stream$putl(po, "33 + 12 = " || int$unparse(sum)) stream$putl(po, "33 - 12 = " || int$unparse(diff)) end start_up

http://rosettacode.org/wiki/Return_multiple_values

Return multiple values

Task Show how to return more than one value from a function.

#CMake

CMake

# Returns the first and last characters of string. function(firstlast string first last) # f = first character. string(SUBSTRING "${string}" 0 1 f) # g = last character. string(LENGTH "${string}" length) math(EXPR index "${length} - 1") string(SUBSTRING "${string}" ${index} 1 g) # Return both characters. set("${first}" "${f}" PARENT_SCOPE) set("${last}" "${g}" PARENT_SCOPE) endfunction(firstlast) firstlast("Rosetta Code" begin end) message(STATUS "begins with ${begin}, ends with ${end}")

http://rosettacode.org/wiki/Rep-string

Rep-string

Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#ALGOL_68

ALGOL 68

# procedure to find the longest rep-string in a given string # # the input string is not validated to contain only "0" and "1" characters # PROC longest rep string = ( STRING input )STRING: BEGIN STRING result := ""; # ensure the string we are working on has a lower-bound of 1 # STRING str = input[ AT 1 ]; # work backwards from half the input string looking for a rep-string # FOR string length FROM UPB str OVER 2 BY -1 TO 1 WHILE STRING left substring = str[ 1 : string length ]; # if the left substgring repeated a sufficient number of times # # (truncated on the right) is equal to the original string, then # # we have found the longest rep-string # STRING repeated string = ( left substring * ( ( UPB str OVER string length ) + 1 ) )[ 1 : UPB str ]; IF str = repeated string THEN # found a rep-string # result := left substring; FALSE ELSE # not a rep-string, keep looking # TRUE FI DO SKIP OD; result END; # longest rep string # # test the longest rep string procedure # main: ( []STRING tests = ( "1001110011" , "1110111011" , "0010010010" , "1010101010" , "1111111111" , "0100101101" , "0100100" , "101" , "11" , "00" , "1" ); FOR test number FROM LWB tests TO UPB tests DO STRING rep string = longest rep string( tests[ test number ] ); print( ( tests[ test number ] , ": " , IF rep string = "" THEN "no rep string" ELSE "longest rep string: """ + rep string + """" FI , newline ) ) OD )

http://rosettacode.org/wiki/Regular_expressions

Regular expressions

Task match a string against a regular expression substitute part of a string using a regular expression

#ALGOL_68

ALGOL 68

INT match=0, no match=1, out of memory error=2, other error=3; STRING str := "i am a string"; # Match: # STRING m := "string$"; INT start, end; IF grep in string(m, str, start, end) = match THEN printf(($"Ends with """g""""l$, str[start:end])) FI; # Replace: # IF sub in string(" a ", " another ",str) = match THEN printf(($gl$, str)) FI;

http://rosettacode.org/wiki/Reverse_a_string

Reverse a string

Task Take a string and reverse it. For example, "asdf" becomes "fdsa". Extra credit Preserve Unicode combining characters. For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa". Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#ACL2

ACL2

(reverse "hello")

http://rosettacode.org/wiki/Rendezvous

Rendezvous

Demonstrate the “rendezvous” communications technique by implementing a printer monitor.

#F.23

F#

open System type PrinterCommand = Print of string // a message is a command and a facility to return an exception type Message = Message of PrinterCommand * AsyncReplyChannel<Exception option> // thrown if we have no more ink (and neither has our possible backup printer) exception OutOfInk type Printer(id, ?backup:Printer) = let mutable ink = 5 // the actual printing logic as a private function let print line = if ink > 0 then printf "%d: " id Seq.iter (printf "%c") line printf "\n" ink <- ink - 1 else match backup with | Some p -> p.Print line | None -> raise OutOfInk // use a MailboxProcessor to process commands asynchronously; // if an exception occurs, we return it to the calling thread let agent = MailboxProcessor.Start( fun inbox -> async { while true do let! Message (command, replyChannel) = inbox.Receive() try match command with | Print line -> print line replyChannel.Reply None with | ex -> replyChannel.Reply (Some ex) }) // public printing method: // send Print command and propagate exception if one occurs member x.Print line = match agent.PostAndReply( fun replyChannel -> Message (Print line, replyChannel) ) with | None -> () | Some ex -> raise ex open System.Threading do let main = new Printer(id=1, backup=new Printer(id=2)) (new Thread(fun () -> try main.Print "Humpty Dumpty sat on a wall." main.Print "Humpty Dumpty had a great fall." main.Print "All the king's horses and all the king's men" main.Print "Couldn't put Humpty together again." with | OutOfInk -> printfn " Humpty Dumpty out of ink!" )).Start() (new Thread(fun () -> try main.Print "Old Mother Goose" main.Print "Would ride through the air" main.Print "On a very fine gander." main.Print "Jack's mother came in," main.Print "And caught the goose soon," main.Print "And mounting its back," main.Print "Flew up to the moon." with | OutOfInk -> printfn " Mother Goose out of ink!" )).Start() Console.ReadLine() |> ignore

http://rosettacode.org/wiki/Repeat

Repeat

Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.

#AWK

AWK

# syntax: GAWK -f REPEAT.AWK BEGIN { for (i=0; i<=3; i++) { f = (i % 2 == 0) ? "even" : "odd" @f(i) # indirect function call } exit(0) } function even(n, i) { for (i=1; i<=n; i++) { printf("inside even %d\n",n) } } function odd(n, i) { for (i=1; i<=n; i++) { printf("inside odd %d\n",n) } }

http://rosettacode.org/wiki/Repeat

Repeat

Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.

#Batch_File

Batch File

@echo off :_main setlocal call:_func1 _func2 3 pause>nul exit/b :_func1 setlocal enabledelayedexpansion for /l %%i in (1,1,%2) do call:%1 exit /b :_func2 setlocal echo _func2 has been executed exit /b

http://rosettacode.org/wiki/Rename_a_file

Rename a file

Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)

#AWK

AWK

$ awk 'BEGIN{system("mv input.txt output.txt")}' $ awk 'BEGIN{system("mv docs mydocs")}' $ awk 'BEGIN{system("mv /input.txt /output.txt")}' $ awk 'BEGIN{system("mv docs mydocs")}'

http://rosettacode.org/wiki/Rename_a_file

Rename a file

Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)

#BaCon

BaCon

RENAME "input.txt" TO "output.txt" RENAME "/input.txt" TO "/output.txt" RENAME "docs" TO "mydocs" RENAME "/docs" TO "/mydocs"

http://rosettacode.org/wiki/RIPEMD-160

RIPEMD-160

RIPEMD-160 is another hash function; it computes a 160-bit message digest. There is a RIPEMD-160 home page, with test vectors and pseudocode for RIPEMD-160. For padding the message, RIPEMD-160 acts like MD4 (RFC 1320). Find the RIPEMD-160 message digest of a string of octets. Use the ASCII encoded string “Rosetta Code”. You may either call an RIPEMD-160 library, or implement RIPEMD-160 in your language.

#zkl

zkl

var MsgHash=Import("zklMsgHash"); MsgHash.RIPEMD160("Rosetta Code")

http://rosettacode.org/wiki/Resistor_mesh

Resistor mesh

Task Given 10×10 grid nodes (as shown in the image) interconnected by 1Ω resistors as shown, find the resistance between points A and B. See also (humor, nerd sniping) xkcd.com cartoon

#Nim

Nim

const S = 10 type NodeKind = enum nodeFree, nodeA, nodeB Node = object v: float fixed: NodeKind Mesh[H, W: static int] = array[H, array[W, Node]] func setBoundary(m: var Mesh) = m[1][1].v = 1.0 m[1][1].fixed = nodeA m[6][7].v = -1.0 m[6][7].fixed = nodeB func calcDiff[H, W: static int](m,: Mesh[H, W]; d: var Mesh[H, W]): float = for i in 0..<H: for j in 0..<W: var v = 0.0 var n = 0 if i > 0: v += m[i - 1][j].v inc n if j > 0: v += m[i][j - 1].v inc n if i + 1 < m.H: v += m[i + 1][j].v inc n if j + 1 < m.W: v += m[i][j + 1].v inc n v = m[i][j].v - v / n.toFloat d[i][j].v = v if m[i][j].fixed == nodeFree: result += v * v func iter[H, W: static int](m: var Mesh[H, W]): float = var d: Mesh[H, W] cur: array[NodeKind, float] diff = 1e10 while diff > 1e-24: m.setBoundary() diff = calcDiff(m, d) for i in 0..<H: for j in 0..<W: m[i][j].v -= d[i][j].v for i in 0..<H: for j in 0..<W: var k = 0 if i != 0: inc k if j != 0: inc k if i < m.H - 1: inc k if j < m.W - 1: inc k cur[m[i][j].fixed] += d[i][j].v * k.toFloat result = (cur[nodeA] - cur[nodeB]) / 2 when isMainModule: var mesh: Mesh[S, S] let r = 2 / mesh.iter() echo "R = ", r

http://rosettacode.org/wiki/Respond_to_an_unknown_method_call

Respond to an unknown method call

Task Demonstrate how to make the object respond (sensibly/usefully) to an invocation of a method on it that it does not support through its class definitions. Note that this is not the same as just invoking a defined method whose name is given dynamically; the method named at the point of invocation must not be defined. This task is intended only for object systems that use a dynamic dispatch mechanism without static checking. Related task Send an unknown method call.

#Slate

Slate

define: #shell &builder: [lobby newSubSpace]. _@shell didNotUnderstand: message at: position "Form a command string and execute it." [ position > 0 ifTrue: [resend] ifFalse: [([| :command | message selector isUnarySelector ifTrue: [command ; message selector. message optionals pairsDo: [| :key :value | command ; ' -' ; (key as: String) allButFirst allButLast ; ' ' ; (value as: String)]]. message selector isKeywordSelector ifTrue: [| keywords args | keywords: ((message selector as: String) splitWith: $:). command ; keywords first. keywords size = 1 ifTrue: "Read a string or array of arguments." [args: message arguments second. (args is: String) ifTrue: [command ; ' ' ; args] ifFalse: [args do: [| :arg | command ; ' ' ; arg]]]]] writingAs: String) ifNil: [resend] ifNotNilDo: [| :cmd | [Platform run: cmd]]] ].

http://rosettacode.org/wiki/Respond_to_an_unknown_method_call

Respond to an unknown method call

Task Demonstrate how to make the object respond (sensibly/usefully) to an invocation of a method on it that it does not support through its class definitions. Note that this is not the same as just invoking a defined method whose name is given dynamically; the method named at the point of invocation must not be defined. This task is intended only for object systems that use a dynamic dispatch mechanism without static checking. Related task Send an unknown method call.

#Smalltalk

Smalltalk

Object subclass: CatchThemAll [ foo [ 'foo received' displayNl ] bar [ 'bar received' displayNl ] doesNotUnderstand: aMessage [ ('message "' , (aMessage selector asString) , '"') displayNl. (aMessage arguments) do: [ :a | 'argument: ' display. a printNl. ] ] ] |a| a := CatchThemAll new. a foo. a bar. a weCanDoIt. a theyCanToo: 'eat' and: 'walk'.

http://rosettacode.org/wiki/Respond_to_an_unknown_method_call

Respond to an unknown method call

Task Demonstrate how to make the object respond (sensibly/usefully) to an invocation of a method on it that it does not support through its class definitions. Note that this is not the same as just invoking a defined method whose name is given dynamically; the method named at the point of invocation must not be defined. This task is intended only for object systems that use a dynamic dispatch mechanism without static checking. Related task Send an unknown method call.

#SuperCollider

SuperCollider

Ingorabilis { tell { "I told you so".postln; } find { "I found nothing".postln } doesNotUnderstand { |selector ... args| "Method selector '%' not understood by %\n".postf(selector, this.class); "Giving you some good arguments in the following".postln; args.do { |x| x.postln }; "And now I delegate the method to my respected superclass".postln; super.doesNotUnderstand(selector, args) } }

http://rosettacode.org/wiki/Reverse_words_in_a_string

Reverse words in a string

Task Reverse the order of all tokens in each of a number of strings and display the result; the order of characters within a token should not be modified. Example Hey you, Bub! would be shown reversed as: Bub! you, Hey Tokens are any non-space characters separated by spaces (formally, white-space); the visible punctuation form part of the word within which it is located and should not be modified. You may assume that there are no significant non-visible characters in the input. Multiple or superfluous spaces may be compressed into a single space. Some strings have no tokens, so an empty string (or one just containing spaces) would be the result. Display the strings in order (1st, 2nd, 3rd, ···), and one string per line. (You can consider the ten strings as ten lines, and the tokens as words.) Input data (ten lines within the box) line ╔════════════════════════════════════════╗ 1 ║ ---------- Ice and Fire ------------ ║ 2 ║ ║ ◄─── a blank line here. 3 ║ fire, in end will world the say Some ║ 4 ║ ice. in say Some ║ 5 ║ desire of tasted I've what From ║ 6 ║ fire. favor who those with hold I ║ 7 ║ ║ ◄─── a blank line here. 8 ║ ... elided paragraph last ... ║ 9 ║ ║ ◄─── a blank line here. 10 ║ Frost Robert ----------------------- ║ ╚════════════════════════════════════════╝ Cf. Phrase reversals

#CoffeeScript

CoffeeScript

strReversed = '---------- Ice and Fire ------------\n\n fire, in end will world the say Some\n ice. in say Some\n desire of tasted I\'ve what From\n fire. favor who those with hold I\n\n ... elided paragraph last ...\n\n Frost Robert -----------------------' reverseString = (s) -> s.split('\n').map((l) -> l.split(/\s/).reverse().join ' ').join '\n' console.log reverseString(strReversed)

http://rosettacode.org/wiki/Rot-13

Rot-13

Task Implement a rot-13 function (or procedure, class, subroutine, or other "callable" object as appropriate to your programming environment). Optionally wrap this function in a utility program (like tr, which acts like a common UNIX utility, performing a line-by-line rot-13 encoding of every line of input contained in each file listed on its command line, or (if no filenames are passed thereon) acting as a filter on its "standard input." (A number of UNIX scripting languages and utilities, such as awk and sed either default to processing files in this way or have command line switches or modules to easily implement these wrapper semantics, e.g., Perl and Python). The rot-13 encoding is commonly known from the early days of Usenet "Netnews" as a way of obfuscating text to prevent casual reading of spoiler or potentially offensive material. Many news reader and mail user agent programs have built-in rot-13 encoder/decoders or have the ability to feed a message through any external utility script for performing this (or other) actions. The definition of the rot-13 function is to simply replace every letter of the ASCII alphabet with the letter which is "rotated" 13 characters "around" the 26 letter alphabet from its normal cardinal position (wrapping around from z to a as necessary). Thus the letters abc become nop and so on. Technically rot-13 is a "mono-alphabetic substitution cipher" with a trivial "key". A proper implementation should work on upper and lower case letters, preserve case, and pass all non-alphabetic characters in the input stream through without alteration. Related tasks Caesar cipher Substitution Cipher Vigenère Cipher/Cryptanalysis Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#PHP

PHP

echo str_rot13('foo'), "\n";

http://rosettacode.org/wiki/Roman_numerals/Encode

Roman numerals/Encode

Task Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero. In Roman numerals: 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC 2008 is written as 2000=MM, 8=VIII; or MMVIII 1666 uses each Roman symbol in descending order: MDCLXVI

#Oz

Oz

declare fun {Digit X Y Z K} unit([X] [X X] [X X X] [X Y] [Y] [Y X] [Y X X] [Y X X X] [X Z]) .K end fun {ToRoman X} if X == 0 then "" elseif X < 0 then raise toRoman(negativeInput X) end elseif X >= 1000 then "M"#{ToRoman X-1000} elseif X >= 100 then {Digit &C &D &M X div 100}#{ToRoman X mod 100} elseif X >= 10 then {Digit &X &L &C X div 10}#{ToRoman X mod 10} else {Digit &I &V &X X} end end in {ForAll {Map [1999 25 944] ToRoman} System.showInfo}

http://rosettacode.org/wiki/Roman_numerals/Decode

Roman numerals/Decode

Task Create a function that takes a Roman numeral as its argument and returns its value as a numeric decimal integer. You don't need to validate the form of the Roman numeral. Modern Roman numerals are written by expressing each decimal digit of the number to be encoded separately, starting with the leftmost decimal digit and skipping any 0s (zeroes). 1990 is rendered as MCMXC (1000 = M, 900 = CM, 90 = XC) and 2008 is rendered as MMVIII (2000 = MM, 8 = VIII). The Roman numeral for 1666, MDCLXVI, uses each letter in descending order.

#QBasic

QBasic

FUNCTION romToDec (roman$) num = 0 prenum = 0 FOR i = LEN(roman$) TO 1 STEP -1 x$ = MID$(roman$, i, 1) n = 0 IF x$ = "M" THEN n = 1000 IF x$ = "D" THEN n = 500 IF x$ = "C" THEN n = 100 IF x$ = "L" THEN n = 50 IF x$ = "X" THEN n = 10 IF x$ = "V" THEN n = 5 IF x$ = "I" THEN n = 1 IF n < preNum THEN num = num - n ELSE num = num + n preNum = n NEXT i romToDec = num END FUNCTION !Testing PRINT "MCMXCIX = "; romToDec("MCMXCIX") '1999 PRINT "MDCLXVI = "; romToDec("MDCLXVI") '1666 PRINT "XXV = "; romToDec("XXV") '25 PRINT "CMLIV = "; romToDec("CMLIV") '954 PRINT "MMXI = "; romToDec("MMXI") '2011

http://rosettacode.org/wiki/Run-length_encoding

Run-length encoding

Run-length encoding You are encouraged to solve this task according to the task description, using any language you may know. Task Given a string containing uppercase characters (A-Z), compress repeated 'runs' of the same character by storing the length of that run, and provide a function to reverse the compression. The output can be anything, as long as you can recreate the input with it. Example Input: WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW Output: 12W1B12W3B24W1B14W Note: the encoding step in the above example is the same as a step of the Look-and-say sequence.

#Wren

Wren

import "/pattern" for Pattern var p = Pattern.new("/u") // match any upper case letter var encode = Fn.new { |s| if (s == "") return s var e = "" var curr = s[0] var count = 1 var i = 1 while (i < s.count) { if (s[i] == curr) { count = count + 1 } else { e = e + count.toString + curr curr = s[i] count = 1 } i = i + 1 } return e + count.toString + curr } var decode = Fn.new { |e| if (e == "") return e var letters = Pattern.matchesText(p.findAll(e)) var numbers = p.splitAll(e)[0..-2].map { |s| Num.fromString(s) }.toList return (0...letters.count).reduce("") { |acc, i| acc + letters[i]*numbers[i] }.join() } var strings = [ "AA", "RROSETTAA", "WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW" ] for (s in strings) { System.print("Original text : %(s)") var e = encode.call(s) System.print("Encoded text : %(e)") var d = decode.call(e) System.print("Decoded text : %(d)") System.print("Original = decoded : %(s == d)\n") }

http://rosettacode.org/wiki/Repeat_a_string

Repeat a string

Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("*", 5) => "*****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#AutoHotkey

AutoHotkey

MsgBox % Repeat("ha",5) Repeat(String,Times) { Loop, %Times% Output .= String Return Output }

http://rosettacode.org/wiki/Return_multiple_values

Return multiple values

Task Show how to return more than one value from a function.

#COBOL

COBOL

identification division. program-id. multiple-values. environment division. configuration section. repository. function multiples function all intrinsic. REPLACE ==:linked-items:== BY == 01 a usage binary-long. 01 b pic x(10). 01 c usage float-short. == ==:record-item:== BY == 01 master. 05 ma usage binary-long. 05 mb pic x(10). 05 mc usage float-short. ==. data division. working-storage section. :linked-items: :record-item: procedure division. sample-main. move 41 to a move "aaaaabbbbb" to b move function e to c display "Original: " a ", " b ", " c call "subprogram" using a b c display "Modified: " a ", " b ", " c move multiples() to master display "Multiple: " ma ", " mb ", " mc goback. end program multiple-values. *> subprogram identification division. program-id. subprogram. data division. linkage section. :linked-items: procedure division using a b c. add 1 to a inspect b converting "a" to "b" divide 2 into c goback. end program subprogram. *> multiples function identification division. function-id. multiples. data division. linkage section. :record-item: procedure division returning master. move 84 to ma move "multiple" to mb move function pi to mc goback. end function multiples.

http://rosettacode.org/wiki/Remove_duplicate_elements

Remove duplicate elements

Sorting Algorithm This is a sorting algorithm. It may be applied to a set of data in order to sort it. For comparing various sorts, see compare sorts. For other sorting algorithms, see sorting algorithms, or: O(n logn) sorts Heap sort | Merge sort | Patience sort | Quick sort O(n log2n) sorts Shell Sort O(n2) sorts Bubble sort | Cocktail sort | Cocktail sort with shifting bounds | Comb sort | Cycle sort | Gnome sort | Insertion sort | Selection sort | Strand sort other sorts Bead sort | Bogo sort | Common sorted list | Composite structures sort | Custom comparator sort | Counting sort | Disjoint sublist sort | External sort | Jort sort | Lexicographical sort | Natural sorting | Order by pair comparisons | Order disjoint list items | Order two numerical lists | Object identifier (OID) sort | Pancake sort | Quickselect | Permutation sort | Radix sort | Ranking methods | Remove duplicate elements | Sleep sort | Stooge sort | [Sort letters of a string] | Three variable sort | Topological sort | Tree sort Given an Array, derive a sequence of elements in which all duplicates are removed. There are basically three approaches seen here: Put the elements into a hash table which does not allow duplicates. The complexity is O(n) on average, and O(n2) worst case. This approach requires a hash function for your type (which is compatible with equality), either built-in to your language, or provided by the user. Sort the elements and remove consecutive duplicate elements. The complexity of the best sorting algorithms is O(n log n). This approach requires that your type be "comparable", i.e., have an ordering. Putting the elements into a self-balancing binary search tree is a special case of sorting. Go through the list, and for each element, check the rest of the list to see if it appears again, and discard it if it does. The complexity is O(n2). The up-shot is that this always works on any type (provided that you can test for equality).

#11l

11l

V items = [‘1’, ‘2’, ‘3’, ‘a’, ‘b’, ‘c’, ‘2’, ‘3’, ‘4’, ‘b’, ‘c’, ‘d’] V unique = Array(Set(items)) print(unique)

http://rosettacode.org/wiki/Reflection/List_properties

Reflection/List properties

Task The goal is to get the properties of an object, as names, values or both. Some languages support dynamic properties, which in general can only be inspected if a class' public API includes a way of listing them.

#C.23

C#

using System; using System.Collections.Generic; using System.Linq; using System.Reflection; public static class Reflection { public static void Main() { var t = new TestClass(); var flags = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance; foreach (var prop in GetPropertyValues(t, flags)) { Console.WriteLine(prop); } foreach (var field in GetFieldValues(t, flags)) { Console.WriteLine(field); } } public static IEnumerable<(string name, object value)> GetPropertyValues<T>(T obj, BindingFlags flags) => from p in typeof(T).GetProperties(flags) where p.GetIndexParameters().Length == 0 //To filter out indexers select (p.Name, p.GetValue(obj, null)); public static IEnumerable<(string name, object value)> GetFieldValues<T>(T obj, BindingFlags flags) => typeof(T).GetFields(flags).Select(f => (f.Name, f.GetValue(obj))); class TestClass { private int privateField = 7; public int PublicNumber { get; } = 4; private int PrivateNumber { get; } = 2; } }

http://rosettacode.org/wiki/Rep-string

Rep-string

Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#APL

APL

rep ← ⊢ (⊢(/⍨)(⊂⊣)≡¨(≢⊣)⍴¨⊢) ⍳∘(⌊0.5×≢)↑¨⊂

http://rosettacode.org/wiki/Rep-string

Rep-string

Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#AppleScript

AppleScript

------------------------REP-CYCLES------------------------- -- repCycles :: String -> [String] on repCycles(xs) set n to length of xs script isCycle on |λ|(cs) xs = takeCycle(n, cs) end |λ| end script filter(isCycle, tail(inits(take(quot(n, 2), xs)))) end repCycles -- cycleReport :: String -> [String] on cycleReport(xs) set reps to repCycles(xs) if isNull(reps) then {xs, "(n/a)"} else {xs, item -1 of reps} end if end cycleReport ---------------------------TEST---------------------------- on run set samples to {"1001110011", "1110111011", "0010010010", ¬ "1010101010", "1111111111", "0100101101", "0100100", ¬ "101", "11", "00", "1"} unlines(cons("Longest cycle:" & linefeed, ¬ map(intercalate(" -> "), ¬ map(cycleReport, samples)))) end run ---------------------GENERIC FUNCTIONS--------------------- -- concat :: [[a]] -> [a] | [String] -> String on concat(xs) if length of xs > 0 and class of (item 1 of xs) is string then set acc to "" else set acc to {} end if repeat with i from 1 to length of xs set acc to acc & item i of xs end repeat acc end concat -- cons :: a -> [a] -> [a] on cons(x, xs) {x} & xs end cons -- filter :: (a -> Bool) -> [a] -> [a] on filter(f, xs) tell mReturn(f) set lst to {} set lng to length of xs repeat with i from 1 to lng set v to item i of xs if |λ|(v, i, xs) then set end of lst to v end repeat return lst end tell end filter -- foldl :: (a -> b -> a) -> a -> [b] -> a on foldl(f, startValue, xs) tell mReturn(f) set v to startValue set lng to length of xs repeat with i from 1 to lng set v to |λ|(v, item i of xs, i, xs) end repeat return v end tell end foldl -- inits :: [a] -> [[a]] -- inits :: String -> [String] on inits(xs) script elemInit on |λ|(_, i, xs) items 1 thru i of xs end |λ| end script script charInit on |λ|(_, i, xs) text 1 thru i of xs end |λ| end script if class of xs is string then {""} & map(charInit, xs) else {{}} & map(elemInit, xs) end if end inits -- intercalate :: Text -> [Text] -> Text on intercalate(strText) script on |λ|(xs) set {dlm, my text item delimiters} to {my text item delimiters, strText} set strJoined to xs as text set my text item delimiters to dlm return strJoined end |λ| end script end intercalate -- map :: (a -> b) -> [a] -> [b] on map(f, xs) tell mReturn(f) set lng to length of xs set lst to {} repeat with i from 1 to lng set end of lst to |λ|(item i of xs, i, xs) end repeat return lst end tell end map -- Lift 2nd class handler function into 1st class script wrapper -- mReturn :: Handler -> Script on mReturn(f) if class of f is script then f else script property |λ| : f end script end if end mReturn -- isNull :: [a] -> Bool on isNull(xs) xs = {} end isNull -- min :: Ord a => a -> a -> a on min(x, y) if y < x then y else x end if end min -- quot :: Integral a => a -> a -> a on quot(n, m) n div m end quot -- replicate :: Int -> a -> [a] on replicate(n, a) set out to {} if n < 1 then return out set dbl to {a} repeat while (n > 1) if (n mod 2) > 0 then set out to out & dbl set n to (n div 2) set dbl to (dbl & dbl) end repeat return out & dbl end replicate -- tail :: [a] -> [a] on tail(xs) if length of xs > 1 then items 2 thru -1 of xs else {} end if end tail -- take :: Int -> [a] -> [a] on take(n, xs) if class of xs is string then if n > 0 then text 1 thru min(n, length of xs) of xs else "" end if else if n > 0 then items 1 thru min(n, length of xs) of xs else {} end if end if end take -- takeCycle :: Int -> [a] -> [a] on takeCycle(n, xs) set lng to length of xs if lng ≥ n then set cycle to xs else set cycle to concat(replicate((n div lng) + 1, xs)) end if if class of xs is string then items 1 thru n of cycle as string else items 1 thru n of cycle end if end takeCycle -- unlines :: [String] -> String on unlines(xs) |λ|(xs) of intercalate(linefeed) end unlines

http://rosettacode.org/wiki/Reflection/Get_source

Reflection/Get source

Task The goal is to get the source code or file path and line number where a programming object (e.g. module, class, function, method) is defined.

#6502_Assembly

6502 Assembly

LDA #<foo sta $00 LDA #>foo sta $01 jsr PrintBytecode foo: ;do stuff rts PrintBytecode: ldy #0 lda $01 ;high byte of starting address of the source jsr PrintHex ;unimplemented routine that separates the "nibbles" of the accumulator, ; adds $30 or $37 to each depending on if it's 0-9 or A-F respectively, which converts hex to ASCII, ; then prints the high nibble then the low. lda $00 ;low byte of the starting address of the source jsr PrintHex jsr NewLine ;unimplemented new line routine loop: lda ($00),y cmp #$60 beq Terminated jsr PrintHex jmp loop Terminated: jsr PrintHex ;print the last instruction of the routine. rts

http://rosettacode.org/wiki/Reflection/Get_source

Reflection/Get source

Task The goal is to get the source code or file path and line number where a programming object (e.g. module, class, function, method) is defined.

#Clojure

Clojure

; Use source function for source code. (source println) ; Use meta function for filenames and line numbers (and other metadata) (meta #'println)

http://rosettacode.org/wiki/Regular_expressions

Regular expressions

Task match a string against a regular expression substitute part of a string using a regular expression

#Amazing_Hopper

Amazing Hopper

#include <hopper.h> main: expReg="[A-Z]{1,2}[0-9][0-9A-Z]? +[0-9][A-Z]{2}" flag compile = REG_EXTENDED flag match=0 número de matches=10, T1=0 {flag compile,expReg} reg compile(T1) // compile regular expression, pointed whit T1 {flag match,número de matches,T1,"We are at SN12 7NY for this course"},reg match, // execute println reg free(T1) // free pointer to regular expression compiled. exit(0)

http://rosettacode.org/wiki/Regular_expressions

Regular expressions

Task match a string against a regular expression substitute part of a string using a regular expression

#AppleScript

AppleScript

try find text ".*string$" in "I am a string" with regexp on error message return message end try try change "original" into "modified" in "I am the original string" with regexp on error message return message end try

http://rosettacode.org/wiki/Reverse_a_string

Reverse a string

Task Take a string and reverse it. For example, "asdf" becomes "fdsa". Extra credit Preserve Unicode combining characters. For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa". Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#Action.21

Action!

PROC Reverse(CHAR ARRAY src,dst) BYTE i,j i=1 j=src(0) dst(0)=j WHILE j>0 DO dst(j)=src(i) i==+1 j==-1 OD RETURN PROC Test(CHAR ARRAY src) CHAR ARRAY dst(40) Reverse(src,dst) PrintF("'%S' -> '%S'%E",src,dst) RETURN PROC Main() Test("Hello World!") Test("123456789") Test("!noitcA iratA") RETURN

http://rosettacode.org/wiki/Rendezvous

Rendezvous

Demonstrate the “rendezvous” communications technique by implementing a printer monitor.

#Go

Go

package main import ( "errors" "fmt" "strings" "sync" ) var hdText = `Humpty Dumpty sat on a wall. Humpty Dumpty had a great fall. All the king's horses and all the king's men, Couldn't put Humpty together again.` var mgText = `Old Mother Goose, When she wanted to wander, Would ride through the air, On a very fine gander. Jack's mother came in, And caught the goose soon, And mounting its back, Flew up to the moon.` func main() { reservePrinter := startMonitor(newPrinter(5), nil) mainPrinter := startMonitor(newPrinter(5), reservePrinter) var busy sync.WaitGroup busy.Add(2) go writer(mainPrinter, "hd", hdText, &busy) go writer(mainPrinter, "mg", mgText, &busy) busy.Wait() } // printer is a type representing an abstraction of a physical printer. // It is a type defintion for a function that takes a string to print // and returns an error value, (hopefully usually nil, meaning no error.) type printer func(string) error // newPrinter is a constructor. The parameter is a quantity of ink. It // returns a printer object encapsulating the ink quantity. // Note that this is not creating the monitor, only the object serving as // a physical printer by writing to standard output. func newPrinter(ink int) printer { return func(line string) error { if ink == 0 { return eOutOfInk } for _, c := range line { fmt.Printf("%c", c) } fmt.Println() ink-- return nil } } var eOutOfInk = errors.New("out of ink") // For the language task, rSync is a type used to approximate the Ada // rendezvous mechanism that includes the caller waiting for completion // of the callee. For this use case, we signal completion with an error // value as a response. Exceptions are not idiomatic in Go and there is // no attempt here to model the Ada exception mechanism. Instead, it is // idomatic in Go to return error values. Sending an error value on a // channel works well here to signal completion. Go unbuffered channels // provide synchronous rendezvous, but call and response takes two channels, // which are bundled together here in a struct. The channel types are chosen // to mirror the parameter and return types of "type printer" defined above. // The channel types here, string and error are both "reference types" // in Go terminology. That is, they are small things containing pointers // to the actual data. Sending one on a channel does not involve copying, // or much less marshalling string data. type rSync struct { call chan string response chan error } // "rendezvous Print" requested by use case task. // For the language task though, it is implemented here as a method on // rSync that sends its argument on rSync.call and returns the result // received from rSync.response. Each channel operation is synchronous. // The two operations back to back approximate the Ada rendezvous. func (r *rSync) print(data string) error { r.call <- data // blocks until data is accepted on channel return <-r.response // blocks until response is received } // monitor is run as a goroutine. It encapsulates the printer passed to it. // Print requests are received through the rSync object "entry," named entry // here to correspond to the Ada concept of an entry point. func monitor(hardPrint printer, entry, reserve *rSync) { for { // The monitor goroutine will block here waiting for a "call" // to its "entry point." data := <-entry.call // Assuming the call came from a goroutine calling rSync.print, // that goroutine is now blocked, waiting for this one to send // a response. // attempt output switch err := hardPrint(data); { // consider return value from attempt case err == nil: entry.response <- nil // no problems case err == eOutOfInk && reserve != nil: // Requeue to "entry point" of reserve printer monitor. // Caller stays blocked, and now this goroutine blocks until // it gets a response from the reserve printer monitor. // It then transparently relays the response to the caller. entry.response <- reserve.print(data) default: entry.response <- err // return failure } // The response is away. Loop, and so immediately block again. } } // startMonitor can be seen as an rSync constructor. It also // of course, starts the monitor for which the rSync serves as entry point. // Further to the langauge task, note that the channels created here are // unbuffered. There is no buffer or message box to hold channel data. // A sender will block waiting for a receiver to accept data synchronously. func startMonitor(p printer, reservePrinter *rSync) *rSync { entry := &rSync{make(chan string), make(chan error)} go monitor(p, entry, reservePrinter) return entry } // Two writer tasks are started as goroutines by main. They run concurrently // and compete for printers as resources. Note the call to "rendezvous Print" // as requested in the use case task and compare the syntax, // Here: printMonitor.print(line); // Ada solution: Main.Print ("string literal"); func writer(printMonitor *rSync, id, text string, busy *sync.WaitGroup) { for _, line := range strings.Split(text, "\n") { if err := printMonitor.print(line); err != nil { fmt.Printf("**** writer task %q terminated: %v ****\n", id, err) break } } busy.Done() }

http://rosettacode.org/wiki/Repeat

Repeat

Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.

#BQN

BQN

•Show {2+𝕩}⍟3 1 _repeat_ ← {(𝕘>0)◶⊢‿(𝔽_𝕣_(𝕘-1)𝔽)𝕩} •Show {2+𝕩} _repeat_ 3 1

http://rosettacode.org/wiki/Repeat

Repeat

Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.

#C

C

#include <stdio.h> void repeat(void (*f)(void), unsigned int n) { while (n-->0) (*f)(); //or just f() } void example() { printf("Example\n"); } int main(int argc, char *argv[]) { repeat(example, 4); return 0; }

http://rosettacode.org/wiki/Rename_a_file

Rename a file

Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)

#BASIC

BASIC

NAME "input.txt" AS "output.txt" NAME "\input.txt" AS "\output.txt" NAME "docs" AS "mydocs" NAME "\docs" AS "\mydocs"

http://rosettacode.org/wiki/Rename_a_file

Rename a file

Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)

#Batch_File

Batch File

ren input.txt output.txt ren \input.txt output.txt ren docs mydocs ren \docs mydocs

http://rosettacode.org/wiki/Resistor_mesh

Resistor mesh

Task Given 10×10 grid nodes (as shown in the image) interconnected by 1Ω resistors as shown, find the resistance between points A and B. See also (humor, nerd sniping) xkcd.com cartoon

#Octave

Octave

N = 10; NN = N*N; G = sparse(NN, NN); node = 0; for row=1:N; for col=1:N; node++; if row > 1 G(node, node)++; G(node, node - N) = -1; end if row < N; G(node, node)++; G(node, node + N) = -1; end if col > 1 G(node, node)++; G(node, node - 1) = -1; end if col < N; G(node, node)++; G(node, node + 1) = -1; end end end current = sparse(NN, 1); Ar = 2; Ac = 2; A = Ac + N*( Ar - 1 ); Br = 7; Bc = 8; B = Bc + N*( Br - 1 ); current( A ) = -1; current( B ) = +1; voltage = G \ current; VA = voltage( A ); VB = voltage( B ); full( abs( VA - VB ) )

http://rosettacode.org/wiki/Respond_to_an_unknown_method_call

Respond to an unknown method call

Task Demonstrate how to make the object respond (sensibly/usefully) to an invocation of a method on it that it does not support through its class definitions. Note that this is not the same as just invoking a defined method whose name is given dynamically; the method named at the point of invocation must not be defined. This task is intended only for object systems that use a dynamic dispatch mechanism without static checking. Related task Send an unknown method call.

#Tcl

Tcl

package require TclOO # First create a simple, conventional class and object oo::class create Example { method foo {} { puts "this is foo" } method bar {} { puts "this is bar" } } Example create example # Modify the object to have a custom ‘unknown method’ interceptor oo::objdefine example { method unknown {name args} { puts "tried to handle unknown method \"$name\"" if {[llength $args]} { puts "it had arguments: $args" } } } # Show off what we can now do... example foo; # prints “this is foo” example bar; # prints “this is bar” example grill; # prints “tried to handle unknown method "grill"” example ding dong; # prints “tried to handle unknown method "ding"” # prints “it had arguments: dong”

http://rosettacode.org/wiki/Respond_to_an_unknown_method_call

Respond to an unknown method call

Task Demonstrate how to make the object respond (sensibly/usefully) to an invocation of a method on it that it does not support through its class definitions. Note that this is not the same as just invoking a defined method whose name is given dynamically; the method named at the point of invocation must not be defined. This task is intended only for object systems that use a dynamic dispatch mechanism without static checking. Related task Send an unknown method call.

#UNIX_Shell

UNIX Shell

function handle_error { status=$? # 127 is: command not found if [[ $status -ne 127 ]]; then return fi lastcmd=$(history | tail -1 | sed 's/^ *[0-9]* *//') read cmd args <<< "$lastcmd" echo "you tried to call $cmd" } # Trap errors. trap 'handle_error' ERR

http://rosettacode.org/wiki/Reverse_words_in_a_string

Reverse words in a string

Task Reverse the order of all tokens in each of a number of strings and display the result; the order of characters within a token should not be modified. Example Hey you, Bub! would be shown reversed as: Bub! you, Hey Tokens are any non-space characters separated by spaces (formally, white-space); the visible punctuation form part of the word within which it is located and should not be modified. You may assume that there are no significant non-visible characters in the input. Multiple or superfluous spaces may be compressed into a single space. Some strings have no tokens, so an empty string (or one just containing spaces) would be the result. Display the strings in order (1st, 2nd, 3rd, ···), and one string per line. (You can consider the ten strings as ten lines, and the tokens as words.) Input data (ten lines within the box) line ╔════════════════════════════════════════╗ 1 ║ ---------- Ice and Fire ------------ ║ 2 ║ ║ ◄─── a blank line here. 3 ║ fire, in end will world the say Some ║ 4 ║ ice. in say Some ║ 5 ║ desire of tasted I've what From ║ 6 ║ fire. favor who those with hold I ║ 7 ║ ║ ◄─── a blank line here. 8 ║ ... elided paragraph last ... ║ 9 ║ ║ ◄─── a blank line here. 10 ║ Frost Robert ----------------------- ║ ╚════════════════════════════════════════╝ Cf. Phrase reversals

#Common_Lisp

Common Lisp

(defun split-and-reverse (str) (labels ((iter (s lst) (let ((s2 (string-trim '(#\space) s))) (if s2 (let ((word-end (position #\space s2))) (if (and word-end (< (1+ word-end) (length s2))) (iter (subseq s2 (1+ word-end)) (cons (subseq s2 0 word-end) lst)) (cons s2 lst))) lst)))) (iter str NIL))) (defparameter *poem* "---------- Ice and Fire ------------ fire, in end will world the say Some ice. in say Some desire of tasted I've what From fire. favor who those with hold I ... elided paragraph last ... Frost Robert -----------------------") (with-input-from-string (s *poem*) (loop for line = (read-line s NIL) while line do (format t "~{~a~#[~:; ~]~}~%" (split-and-reverse line))))

http://rosettacode.org/wiki/Rot-13

Rot-13

Task Implement a rot-13 function (or procedure, class, subroutine, or other "callable" object as appropriate to your programming environment). Optionally wrap this function in a utility program (like tr, which acts like a common UNIX utility, performing a line-by-line rot-13 encoding of every line of input contained in each file listed on its command line, or (if no filenames are passed thereon) acting as a filter on its "standard input." (A number of UNIX scripting languages and utilities, such as awk and sed either default to processing files in this way or have command line switches or modules to easily implement these wrapper semantics, e.g., Perl and Python). The rot-13 encoding is commonly known from the early days of Usenet "Netnews" as a way of obfuscating text to prevent casual reading of spoiler or potentially offensive material. Many news reader and mail user agent programs have built-in rot-13 encoder/decoders or have the ability to feed a message through any external utility script for performing this (or other) actions. The definition of the rot-13 function is to simply replace every letter of the ASCII alphabet with the letter which is "rotated" 13 characters "around" the 26 letter alphabet from its normal cardinal position (wrapping around from z to a as necessary). Thus the letters abc become nop and so on. Technically rot-13 is a "mono-alphabetic substitution cipher" with a trivial "key". A proper implementation should work on upper and lower case letters, preserve case, and pass all non-alphabetic characters in the input stream through without alteration. Related tasks Caesar cipher Substitution Cipher Vigenère Cipher/Cryptanalysis Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#Picat

Picat

go => S = "Big fjords vex quick waltz nymph!", println(S), println(rot13(S)), println(rot13(rot13(S))), nl. % Rot 13 using a map rot13(S) = S2 => lower(Lower), upper(Upper), M = create_map(Lower, Upper), % If a char is not in a..zA..z then show it as it is. S2 := [M.get(C,C) : C in S]. create_map(Lower, Upper) = M => M = new_map(), Len = Lower.length, LDiv := Lower.length div 2, foreach(I in 1..Len) II = (LDiv+I) mod Len, if II == 0 then II := Len end, M.put(Upper[I],Upper[II]), M.put(Lower[I],Lower[II]) end. lower("abcdefghijklmnopqrstuvwxyz"). upper("ABCDEFGHIJKLMNOPQRSTUVWXYZ").

http://rosettacode.org/wiki/Roman_numerals/Encode

Roman numerals/Encode

Task Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero. In Roman numerals: 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC 2008 is written as 2000=MM, 8=VIII; or MMVIII 1666 uses each Roman symbol in descending order: MDCLXVI

#PARI.2FGP

PARI/GP

oldRoman(n)={ while(n>999999, n-=1000000; print1("((((I))))") ); if(n>499999, n-=500000; print1("I))))") ); while(n>99999, n-=100000; print1("(((I)))") ); if(n>49999, n-=50000; print1("I)))") ); while(n>9999, n-=10000; print1("((I))") ); if(n>4999, n-=5000; print1("I))") ); while(n>999, n-=1000; print1("(I)") ); if(n>499, n-=500; print1("I)") ); while(n>99, n-=100; print1("C") ); if(n>49, n-=50; print1("L"); ); while(n>9, n-=10; print1("X") ); if(n>4, n-=5; print1("V"); ); while(n, n--; print1("I") ); print() };

http://rosettacode.org/wiki/Roman_numerals/Decode

Roman numerals/Decode

Task Create a function that takes a Roman numeral as its argument and returns its value as a numeric decimal integer. You don't need to validate the form of the Roman numeral. Modern Roman numerals are written by expressing each decimal digit of the number to be encoded separately, starting with the leftmost decimal digit and skipping any 0s (zeroes). 1990 is rendered as MCMXC (1000 = M, 900 = CM, 90 = XC) and 2008 is rendered as MMVIII (2000 = MM, 8 = VIII). The Roman numeral for 1666, MDCLXVI, uses each letter in descending order.

#Quackery

Quackery

[ 2dup < if [ dip [ 2 * - ] dup ] nip dup rot + swap ] is roman ( t p n --> t p ) [ 1 roman ] is I ( t p --> t p ) [ 5 roman ] is V ( t p --> t p ) [ 10 roman ] is X ( t p --> t p ) [ 50 roman ] is L ( t p --> t p ) [ 100 roman ] is C ( t p --> t p ) [ 500 roman ] is D ( t p --> t p ) [ 1000 roman ] is M ( t p --> t p ) [ 0 1000 rot $ "" swap witheach [ space join join ] quackery drop ] is ->arabic ( $ --> n ) $ " MCMXC" dup echo$ say " = " ->arabic echo cr $ " MMVIII" dup echo$ say " = " ->arabic echo cr $ "MDCLXVI" dup echo$ say " = " ->arabic echo cr cr $ "I MIX VIVID MILD MIMIC" dup echo$ say " = " ->arabic echo cr

http://rosettacode.org/wiki/Run-length_encoding

Run-length encoding

Run-length encoding You are encouraged to solve this task according to the task description, using any language you may know. Task Given a string containing uppercase characters (A-Z), compress repeated 'runs' of the same character by storing the length of that run, and provide a function to reverse the compression. The output can be anything, as long as you can recreate the input with it. Example Input: WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW Output: 12W1B12W3B24W1B14W Note: the encoding step in the above example is the same as a step of the Look-and-say sequence.

#XPL0

XPL0

include c:\cxpl\codes; \intrinsic 'code' declarations string 0; \use zero-terminated strings, instead of MSb terminated proc Compress(S); \Compress string using run-length encoding, & display it char S; int I, C0, C, N; [I:= 0; C0:= S(I); I:= I+1; repeat ChOut(0, C0); N:= 0; repeat C:= S(I); I:= I+1; N:= N+1; until C#C0; if N>1 then IntOut(0, N-1); C0:= C; until C=0; ]; \Compress proc Expand(S); \Expand compressed string, and display it char S; int I, C0, C, N; [I:= 0; C0:= S(I); I:= I+1; repeat ChOut(0, C0); C:= S(I); I:= I+1; if C>=^1 & C<=^9 then [N:= 0; while C>=^0 & C<=^9 do [N:= N*10 + C-^0; C:= S(I); I:= I+1; ]; while N do [ChOut(0, C0); N:= N-1]; ]; C0:= C; until C=0; ]; \Expand [Compress("WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW"); CrLf(0); Expand("W11BW11B2W23BW13"); CrLf(0); ]

http://rosettacode.org/wiki/Repeat_a_string

Repeat a string

Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("*", 5) => "*****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#AutoIt

AutoIt

#include <String.au3> ConsoleWrite(_StringRepeat("ha", 5) & @CRLF)

http://rosettacode.org/wiki/Return_multiple_values

Return multiple values

Task Show how to return more than one value from a function.

#Common_Lisp

Common Lisp

(defun return-three () 3)

http://rosettacode.org/wiki/Return_multiple_values

Return multiple values

Task Show how to return more than one value from a function.

#Cowgol

Cowgol

include "cowgol.coh"; # In Cowgol, subroutines can simply define multiple output parameters. sub MinMax(arr: [uint8], len: intptr): (min: uint8, max: uint8) is min := 255; max := 0; while len > 0 loop len := len - 1; var cur := [arr]; if min > cur then min := cur; end if; if max < cur then max := cur; end if; arr := @next arr; end loop; # Values are also returned automatically. end sub; # Example of usage: var nums: uint8[] := {23, 65, 33, 12, 95, 5, 32, 91, 135, 25, 8}; var least: uint8; var most: uint8; # Accept two output parameters from a function (least, most) := MinMax(&nums[0], @sizeof nums); print("Min: "); print_i8(least); print_nl(); print("Max: "); print_i8(most); print_nl();

http://rosettacode.org/wiki/Remove_duplicate_elements

Remove duplicate elements

Sorting Algorithm This is a sorting algorithm. It may be applied to a set of data in order to sort it. For comparing various sorts, see compare sorts. For other sorting algorithms, see sorting algorithms, or: O(n logn) sorts Heap sort | Merge sort | Patience sort | Quick sort O(n log2n) sorts Shell Sort O(n2) sorts Bubble sort | Cocktail sort | Cocktail sort with shifting bounds | Comb sort | Cycle sort | Gnome sort | Insertion sort | Selection sort | Strand sort other sorts Bead sort | Bogo sort | Common sorted list | Composite structures sort | Custom comparator sort | Counting sort | Disjoint sublist sort | External sort | Jort sort | Lexicographical sort | Natural sorting | Order by pair comparisons | Order disjoint list items | Order two numerical lists | Object identifier (OID) sort | Pancake sort | Quickselect | Permutation sort | Radix sort | Ranking methods | Remove duplicate elements | Sleep sort | Stooge sort | [Sort letters of a string] | Three variable sort | Topological sort | Tree sort Given an Array, derive a sequence of elements in which all duplicates are removed. There are basically three approaches seen here: Put the elements into a hash table which does not allow duplicates. The complexity is O(n) on average, and O(n2) worst case. This approach requires a hash function for your type (which is compatible with equality), either built-in to your language, or provided by the user. Sort the elements and remove consecutive duplicate elements. The complexity of the best sorting algorithms is O(n log n). This approach requires that your type be "comparable", i.e., have an ordering. Putting the elements into a self-balancing binary search tree is a special case of sorting. Go through the list, and for each element, check the rest of the list to see if it appears again, and discard it if it does. The complexity is O(n2). The up-shot is that this always works on any type (provided that you can test for equality).

#360_Assembly

360 Assembly

* Remove duplicate elements - 18/10/2015 REMDUP CSECT USING REMDUP,R15 set base register SR R6,R6 i=0 LA R8,1 k=1 LOOPK C R8,N do k=1 to n BH ELOOPK LR R1,R8 k SLA R1,2 L R9,T-4(R1) e=t(k) LR R7,R8 k BCTR R7,0 j=k-1 LOOPJ C R7,=F'1' do j=k-1 to 1 by -1 BL ELOOPJ LR R1,R7 j SLA R1,2 L R2,T-4(R1) t(j) CR R9,R2 if e=t(j) then goto iter BE ITER BCTR R7,0 j=j-1 B LOOPJ ELOOPJ LA R6,1(R6) i=i+1 LR R1,R6 i SLA R1,2 ST R9,T-4(R1) t(i)=e ITER LA R8,1(R8) k=k+1 B LOOPK ELOOPK LA R10,PG pgi=@pg LA R8,1 k=1 LOOP CR R8,R6 do k=1 to i BH ELOOP LR R1,R8 k SLA R1,2 L R2,T-4(R1) t(k) XDECO R2,PG+80 edit t(k) MVC 0(3,R10),PG+89 output t(k) on 3 char LA R10,3(R10) pgi=pgi+3 LA R8,1(R8) k=k+1 B LOOP ELOOP XPRNT PG,80 print buffer XR R15,R15 set return code BR R14 return to caller T DC F'6',F'6',F'1',F'5',F'6',F'2',F'1',F'7',F'5',F'22' DC F'4',F'19',F'1',F'1',F'6',F'8',F'9',F'10',F'11',F'12' N DC A((N-T)/4) number of T items PG DC CL92' ' YREGS END REMDUP

http://rosettacode.org/wiki/Reflection/List_properties

Reflection/List properties

Task The goal is to get the properties of an object, as names, values or both. Some languages support dynamic properties, which in general can only be inspected if a class' public API includes a way of listing them.

#D

D

import std.stdio; struct S { bool b; void foo() {} private void bar() {} } class C { bool b; void foo() {} private void bar() {} } void printProperties(T)() if (is(T == class) || is(T == struct)) { import std.stdio; import std.traits; writeln("Properties of ", T.stringof, ':'); foreach (m; __traits(allMembers, T)) { static if (__traits(compiles, (typeof(__traits(getMember, T, m))))) { alias typeof(__traits(getMember, T, m)) ti; static if (!isFunction!ti) { writeln(" ", m); } } } } void main() { printProperties!S; printProperties!C; }

http://rosettacode.org/wiki/Reflection/List_properties

Reflection/List properties

Task The goal is to get the properties of an object, as names, values or both. Some languages support dynamic properties, which in general can only be inspected if a class' public API includes a way of listing them.

#Elena

Elena

import system'routines; import system'dynamic; import extensions; class MyClass { prop int X; prop string Y; } public program() { var o := new MyClass { this X := 2; this Y := "String"; }; MyClass.__getProperties().forEach:(p) { console.printLine("o.",p,"=",cast MessageName(p).getPropertyValue(o)) } }

http://rosettacode.org/wiki/Rep-string

Rep-string

Given a series of ones and zeroes in a string, define a repeated string or rep-string as a string which is created by repeating a substring of the first N characters of the string truncated on the right to the length of the input string, and in which the substring appears repeated at least twice in the original. For example, the string 10011001100 is a rep-string as the leftmost four characters of 1001 are repeated three times and truncated on the right to give the original string. Note that the requirement for having the repeat occur two or more times means that the repeating unit is never longer than half the length of the input string. Task Write a function/subroutine/method/... that takes a string and returns an indication of if it is a rep-string and the repeated string. (Either the string that is repeated, or the number of repeated characters would suffice). There may be multiple sub-strings that make a string a rep-string - in that case an indication of all, or the longest, or the shortest would suffice. Use the function to indicate the repeating substring if any, in the following: 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 Show your output on this page. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#Arturo

Arturo

repeated?: function [text][ loop ((size text)/2)..0 'x [ if prefix? text slice text x (size text)-1 [ (x>0)? -> return slice text 0 x-1 -> return false ] ] return false ] strings: { 1001110011 1110111011 0010010010 1010101010 1111111111 0100101101 0100100 101 11 00 1 } loop split.lines strings 'str [ rep: repeated? str if? false = rep -> print [str "-> *not* a rep-string"] else -> print [str "->" rep "( length:" size rep ")"] ]

http://rosettacode.org/wiki/Reflection/Get_source

Reflection/Get source

Task The goal is to get the source code or file path and line number where a programming object (e.g. module, class, function, method) is defined.

#Factor

Factor

USE: see \ integer see ! class nl \ dip see ! word

http://rosettacode.org/wiki/Reflection/Get_source

Reflection/Get source

Task The goal is to get the source code or file path and line number where a programming object (e.g. module, class, function, method) is defined.

#FreeBASIC

FreeBASIC

' FB 1.05.0 Win64 (getsource.bas) Sub Proc() Print __Function__ & " is defined in " & __Path__ & "\" & __File__ & " at line " & ( __line__ - 1) End Sub Proc() Sleep

http://rosettacode.org/wiki/Reflection/Get_source

Reflection/Get source

Task The goal is to get the source code or file path and line number where a programming object (e.g. module, class, function, method) is defined.

#Go

Go

package main import ( "fmt" "path" "reflect" "runtime" ) func someFunc() { fmt.Println("someFunc called") } func main() { pc := reflect.ValueOf(someFunc).Pointer() f := runtime.FuncForPC(pc) name := f.Name() file, line := f.FileLine(pc) fmt.Println("Name of function :", name) fmt.Println("Name of file :", path.Base(file)) fmt.Println("Line number :", line) }

http://rosettacode.org/wiki/Reflection/Get_source

Reflection/Get source

Task The goal is to get the source code or file path and line number where a programming object (e.g. module, class, function, method) is defined.

#J

J

mean=:+/ %# 5!:5 <'mean' +/ % # 5!:6 <'mean' (+/) % # 4!:4 <'mean' _1 4!:4 <'names' 2 2 { 4!:3 '' ┌────────────────────────────────────────────┐ │/Applications/j64-804/system/main/stdlib.ijs│ └────────────────────────────────────────────┘

http://rosettacode.org/wiki/Regular_expressions

Regular expressions

Task match a string against a regular expression substitute part of a string using a regular expression

#Argile

Argile

use std, regex (: matching :) if "some matchable string" =~ /^some" "+[a-z]*" "+string$/ echo string matches else echo string "doesn't" match (: replacing :) let t = strdup "some allocated string" t =~ s/a/"4"/g t =~ s/e/"3"/g t =~ s/i/"1"/g t =~ s/o/"0"/g t =~ s/s/$/g print t free t (: flushing regex allocations :) uninit regex check mem leak; use dbg (:optional:)

http://rosettacode.org/wiki/Regular_expressions

Regular expressions

Task match a string against a regular expression substitute part of a string using a regular expression

#Arturo

Arturo

s: "This is a string" if contains? s {/string$/} -> print "yes, it ends with 'string'" replace 's {/[as]/} "x" print s

http://rosettacode.org/wiki/Reverse_a_string

Reverse a string

Task Take a string and reverse it. For example, "asdf" becomes "fdsa". Extra credit Preserve Unicode combining characters. For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa". Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#ActionScript

ActionScript

function reverseString(string:String):String { var reversed:String = new String(); for(var i:int = string.length -1; i >= 0; i--) reversed += string.charAt(i); return reversed; } function reverseStringCQAlternative(string:String):String { return string.split('').reverse().join(''); }

http://rosettacode.org/wiki/Rendezvous

Rendezvous

Demonstrate the “rendezvous” communications technique by implementing a printer monitor.

#Julia

Julia

mutable struct Printer inputpath::Channel{String} errorpath::Channel{String} inkremaining::Int32 reserve::Printer name::String function Printer(ch1, ch2, ink, name) this = new() this.inputpath = ch1 this.errorpath = ch2 this.inkremaining = ink this.name = name this.reserve = this this end end function lineprintertask(printer) while true line = take!(printer.inputpath) linesprinted = 0 if(printer.inkremaining < 1) if(printer.reserve == printer) put!(printer.errorpath, "Error: printer $(printer.name) out of ink") else put!(printer.reserve.inputpath, line) end else println(line) printer.inkremaining -= 1 end end end function schedulework(poems) printerclose(printer) = (close(printer.inputpath); close(printer.errorpath)) reserveprinter = Printer(Channel{String}(1), Channel{String}(10), 5, "Reserve") mainprinter = Printer(Channel{String}(1), Channel{String}(10), 5, "Main") mainprinter.reserve = reserveprinter @async(lineprintertask(mainprinter)) @async(lineprintertask(reserveprinter)) printers = [mainprinter, reserveprinter] activeprinter = 1 @sync( for poem in poems activeprinter = (activeprinter % length(printers)) + 1 @async( for line in poem put!(printers[activeprinter].inputpath, line) end) end) for p in printers while isready(p.errorpath) println(take!(p.errorpath)) end printerclose(p) end end const humptydumpty = ["Humpty Dumpty sat on a wall.", "Humpty Dumpty had a great fall.", "All the king's horses and all the king's men,", "Couldn't put Humpty together again."] const oldmothergoose = ["Old Mother Goose,", "When she wanted to wander,", "Would ride through the air,", "On a very fine gander.", "Jack's mother came in,", "And caught the goose soon,", "And mounting its back,", "Flew up to the moon."] schedulework([humptydumpty, oldmothergoose])

http://rosettacode.org/wiki/Rendezvous

Rendezvous

Demonstrate the “rendezvous” communications technique by implementing a printer monitor.

#Nim

Nim

import asyncdispatch, options, strutils type Printer = ref object inkLevel, id: int backup: Option[Printer] OutOfInkException = object of IOError proc print(p: Printer, line: string){.async.} = if p.inkLevel <= 0: if p.backup.isNone(): raise newException(OutOfInkException, "out of ink") else: await p.backup.get().print(line) else: p.inkLevel-=1 stdout.writeLine("$1:$2".format(p.id, line)) await sleepAsync(100) proc newPrinter(inkLevel, id: int, backup: Option[Printer]): Printer = new(result) result.inkLevel = inkLevel result.id = id result.backup = backup proc print(p: Printer, msg: seq[string]){.async.} = for line in msg: try: await p.print(line) except OutOfInkException as e: echo("out of ink") break const humptyLines = @[ "Humpty Dumpty sat on a wall.", "Humpty Dumpty had a great fall.", "All the king's horses and all the king's men,", "Couldn't put Humpty together again.", ] gooseLines = @[ "Old Mother Goose,", "When she wanted to wander,", "Would ride through the air,", "On a very fine gander.", "Jack's mother came in,", "And caught the goose soon,", "And mounting its back,", "Flew up to the moon.", ] proc main(){.async.} = var reservePrinter = newPrinter(5, 2, none(Printer)) mainPrinter = newPrinter(5, 1, some(reservePrinter)) await mainPrinter.print(gooseLines) and mainPrinter.print(humptyLines) waitFor main()

http://rosettacode.org/wiki/Rendezvous

Rendezvous

Demonstrate the “rendezvous” communications technique by implementing a printer monitor.

#Oz

Oz

declare class Printer attr ink:5 feat id backup meth init(id:ID backup:Backup<=unit) self.id = ID self.backup = Backup end meth print(Line)=Msg if @ink == 0 then if self.backup == unit then raise outOfInk end else {self.backup Msg} end else {System.printInfo self.id#": "} for C in Line do {System.printInfo [C]} end {System.printInfo "\n"} ink := @ink - 1 end end end

http://rosettacode.org/wiki/Repeat

Repeat

Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.

#C.23

C#

using System; namespace Repeat { class Program { static void Repeat(int count, Action<int> fn) { if (null == fn) { throw new ArgumentNullException("fn"); } for (int i = 0; i < count; i++) { fn.Invoke(i + 1); } } static void Main(string[] args) { Repeat(3, x => Console.WriteLine("Example {0}", x)); } } }

http://rosettacode.org/wiki/Repeat

Repeat

Task Write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.

#C.2B.2B

C++

template <typename Function> void repeat(Function f, unsigned int n) { for(unsigned int i=n; 0<i; i--) f(); }

http://rosettacode.org/wiki/Rename_a_file

Rename a file

Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)

#BBC_BASIC

BBC BASIC

*RENAME input.txt output.txt *RENAME \input.txt \output.txt *RENAME docs. mydocs. *RENAME \docs. \mydocs.

http://rosettacode.org/wiki/Rename_a_file

Rename a file

Task Rename: a file called input.txt into output.txt and a directory called docs into mydocs. This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root. It can be assumed that the user has the rights to do so. (In unix-type systems, only the user root would have sufficient permissions in the filesystem root.)

#Bracmat

Bracmat

ren$("input.txt"."output.txt") { 'ren' is based on standard C function 'rename()' } ren$(docs.mydocs) { No quotes needed: names don't contain dots or colons. } ren$("d:\\input.txt"."d:\\output.txt") { Backslash is escape character, so we need to escape it. } ren$(@"d:\docs".@"d:\mydocs") { @ used as syntactic sugar as in C# for inhibiting escape. }

http://rosettacode.org/wiki/Resistor_mesh

Resistor mesh

Task Given 10×10 grid nodes (as shown in the image) interconnected by 1Ω resistors as shown, find the resistance between points A and B. See also (humor, nerd sniping) xkcd.com cartoon

#Perl

Perl

use strict; use warnings; my ($w, $h) = (9, 9); my @v = map([ (0) x ($w + 1) ], 0 .. $h); # voltage my @f = map([ (0) x ($w + 1) ], 0 .. $h); # fixed condition my @d = map([ (0) x ($w + 1) ], 0 .. $h); # diff my @n; # neighbors for my $i (0 .. $h) { push @{$n[$i][$_]}, [$i, $_ - 1] for 1 .. $w; push @{$n[$i][$_]}, [$i, $_ + 1] for 0 .. $w - 1; } for my $j (0 .. $w) { push @{$n[$_][$j]}, [$_ - 1, $j] for 1 .. $h; push @{$n[$_][$j]}, [$_ + 1, $j] for 0 .. $h - 1; } sub set_boundary { $f[1][1] = 1; $f[6][7] = -1; $v[1][1] = 1; $v[6][7] = -1; } sub calc_diff { my $total_diff; for my $i (0 .. $h) { for my $j (0 .. $w) { my ($p, $v) = $n[$i][$j]; $v += $v[$_->[0]][$_->[1]] for @$p; $d[$i][$j] = $v = $v[$i][$j] - $v / scalar(@$p); $total_diff += $v * $v unless $f[$i][$j]; } } $total_diff; } sub iter { my $diff = 1; while ($diff > 1e-15) { set_boundary(); $diff = calc_diff(); #print "error^2: $diff\n"; # un-comment to see slow convergence for my $i (0 .. $h) { for my $j (0 .. $w) { $v[$i][$j] -= $d[$i][$j]; } } } my @current = (0) x 3; for my $i (0 .. $h) { for my $j (0 .. $w) { $current[ $f[$i][$j] ] += $d[$i][$j] * scalar(@{$n[$i][$j]}); } } return ($current[1] - $current[-1]) / 2; } printf "R = %.6f\n", 2 / iter();

http://rosettacode.org/wiki/Respond_to_an_unknown_method_call

Respond to an unknown method call

Task Demonstrate how to make the object respond (sensibly/usefully) to an invocation of a method on it that it does not support through its class definitions. Note that this is not the same as just invoking a defined method whose name is given dynamically; the method named at the point of invocation must not be defined. This task is intended only for object systems that use a dynamic dispatch mechanism without static checking. Related task Send an unknown method call.

#Wren

Wren

import "io" for Stdin, Stdout class Test { construct new() {} foo() { System.print("Foo called.") } bar() { System.print("Bar called.") } missingMethod(m) { System.print(m) System.write("Try and continue anyway y/n ? ") Stdout.flush() var reply = Stdin.readLine() if (reply != "y" && reply != "Y") { Fiber.abort("Decided to abort due to missing method.") } } } var test = Test.new() var f = Fiber.new { test.foo() test.bar() test.baz() } f.try() var err = f.error if (err) { if (err.startsWith("Test does not implement")) { test.missingMethod(err) } else { Fiber.abort(err) // rethrow other errors } } System.print("OK, continuing.")

http://rosettacode.org/wiki/Respond_to_an_unknown_method_call

Respond to an unknown method call

Task Demonstrate how to make the object respond (sensibly/usefully) to an invocation of a method on it that it does not support through its class definitions. Note that this is not the same as just invoking a defined method whose name is given dynamically; the method named at the point of invocation must not be defined. This task is intended only for object systems that use a dynamic dispatch mechanism without static checking. Related task Send an unknown method call.

#zkl

zkl

class C{ fcn __notFound(name){println(name," not in ",self); bar} fcn bar{vm.arglist.println("***")} }

http://rosettacode.org/wiki/Reverse_words_in_a_string

Reverse words in a string

Task Reverse the order of all tokens in each of a number of strings and display the result; the order of characters within a token should not be modified. Example Hey you, Bub! would be shown reversed as: Bub! you, Hey Tokens are any non-space characters separated by spaces (formally, white-space); the visible punctuation form part of the word within which it is located and should not be modified. You may assume that there are no significant non-visible characters in the input. Multiple or superfluous spaces may be compressed into a single space. Some strings have no tokens, so an empty string (or one just containing spaces) would be the result. Display the strings in order (1st, 2nd, 3rd, ···), and one string per line. (You can consider the ten strings as ten lines, and the tokens as words.) Input data (ten lines within the box) line ╔════════════════════════════════════════╗ 1 ║ ---------- Ice and Fire ------------ ║ 2 ║ ║ ◄─── a blank line here. 3 ║ fire, in end will world the say Some ║ 4 ║ ice. in say Some ║ 5 ║ desire of tasted I've what From ║ 6 ║ fire. favor who those with hold I ║ 7 ║ ║ ◄─── a blank line here. 8 ║ ... elided paragraph last ... ║ 9 ║ ║ ◄─── a blank line here. 10 ║ Frost Robert ----------------------- ║ ╚════════════════════════════════════════╝ Cf. Phrase reversals

#D

D

void main() { import std.stdio, std.string, std.range, std.algorithm; immutable text = "---------- Ice and Fire ------------ fire, in end will world the say Some ice. in say Some desire of tasted I've what From fire. favor who those with hold I ... elided paragraph last ... Frost Robert -----------------------"; writefln("%(%-(%s %)\n%)", text.splitLines.map!(r => r.split.retro)); }

http://rosettacode.org/wiki/Rot-13

Rot-13

Task Implement a rot-13 function (or procedure, class, subroutine, or other "callable" object as appropriate to your programming environment). Optionally wrap this function in a utility program (like tr, which acts like a common UNIX utility, performing a line-by-line rot-13 encoding of every line of input contained in each file listed on its command line, or (if no filenames are passed thereon) acting as a filter on its "standard input." (A number of UNIX scripting languages and utilities, such as awk and sed either default to processing files in this way or have command line switches or modules to easily implement these wrapper semantics, e.g., Perl and Python). The rot-13 encoding is commonly known from the early days of Usenet "Netnews" as a way of obfuscating text to prevent casual reading of spoiler or potentially offensive material. Many news reader and mail user agent programs have built-in rot-13 encoder/decoders or have the ability to feed a message through any external utility script for performing this (or other) actions. The definition of the rot-13 function is to simply replace every letter of the ASCII alphabet with the letter which is "rotated" 13 characters "around" the 26 letter alphabet from its normal cardinal position (wrapping around from z to a as necessary). Thus the letters abc become nop and so on. Technically rot-13 is a "mono-alphabetic substitution cipher" with a trivial "key". A proper implementation should work on upper and lower case letters, preserve case, and pass all non-alphabetic characters in the input stream through without alteration. Related tasks Caesar cipher Substitution Cipher Vigenère Cipher/Cryptanalysis Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#PicoLisp

PicoLisp

(de rot13-Ch (C) (if (or (member C '`(apply circ (chop "ABCDEFGHIJKLMNOPQRSTUVWXYZ"))) (member C '`(apply circ (chop "abcdefghijklmnopqrstuvwxyz"))) ) (get @ 14) C ) )

http://rosettacode.org/wiki/Roman_numerals/Encode

Roman numerals/Encode

Task Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero. In Roman numerals: 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC 2008 is written as 2000=MM, 8=VIII; or MMVIII 1666 uses each Roman symbol in descending order: MDCLXVI

#Pascal

Pascal

http://rosettacode.org/wiki/Roman_numerals/Decode

Roman numerals/Decode

Task Create a function that takes a Roman numeral as its argument and returns its value as a numeric decimal integer. You don't need to validate the form of the Roman numeral. Modern Roman numerals are written by expressing each decimal digit of the number to be encoded separately, starting with the leftmost decimal digit and skipping any 0s (zeroes). 1990 is rendered as MCMXC (1000 = M, 900 = CM, 90 = XC) and 2008 is rendered as MMVIII (2000 = MM, 8 = VIII). The Roman numeral for 1666, MDCLXVI, uses each letter in descending order.

#QB64

QB64

SCREEN _NEWIMAGE(400, 600, 32) CLS Main: '------------------------------------------------ ' CALLS THE romToDec FUNCTION WITH THE ROMAN ' NUMERALS AND RETURNS ITS DECIMAL EQUIVELENT. ' PRINT "ROMAN NUMERAL TO DECIMAL CONVERSION" PRINT: PRINT PRINT "MDCCIV = "; romToDec("MDCCIV") '1704 PRINT "MCMXC = "; romToDec("MCMXC") '1990 PRINT "MMVIII = "; romToDec("MMVIII") '2008 PRINT "MDCLXVI = "; romToDec("MDCLXVI") '1666 PRINT: PRINT PRINT "Here are other solutions not from the TASK:" PRINT "MCMXCIX = "; romToDec("MCMXCIX") '1999 PRINT "XXV = "; romToDec("XXV") '25 PRINT "CMLIV = "; romToDec("CMLIV") '954 PRINT "MMXI = "; romToDec("MMXI") '2011 PRINT "MMIIIX = "; romToDec("MMIIIX") '2011 PRINT: PRINT PRINT "2011 can be written either as MMXI or MMIIIX" PRINT "With the IX = 9, MMIIIX is also 2011." PRINT "2011 IS CORRECT (MM=2000 + II = 2 + IX = 9)" END FUNCTION romToDec (roman AS STRING) '------------------------------------------------------ ' FUNCTION THAT CONVERTS ANY ROMAN NUMERAL TO A DECIMAL ' prenum = 0: num = 0 LN = LEN(roman) FOR i = LN TO 1 STEP -1 x$ = MID$(roman, i, 1) n = 1000 SELECT CASE x$ CASE "M": n = n / 1 CASE "D": n = n / 2 CASE "C": n = n / 10 CASE "L": n = n / 20 CASE "X": n = n / 100 CASE "V": n = n / 200 CASE "I": n = n / n CASE ELSE: n = 0 END SELECT IF n < prenum THEN num = num - n ELSE num = num + n prenum = n NEXT i romToDec = num END FUNCTION

http://rosettacode.org/wiki/Run-length_encoding

Run-length encoding

Run-length encoding You are encouraged to solve this task according to the task description, using any language you may know. Task Given a string containing uppercase characters (A-Z), compress repeated 'runs' of the same character by storing the length of that run, and provide a function to reverse the compression. The output can be anything, as long as you can recreate the input with it. Example Input: WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW Output: 12W1B12W3B24W1B14W Note: the encoding step in the above example is the same as a step of the Look-and-say sequence.

#zkl

zkl

http://rosettacode.org/wiki/Repeat_a_string

Repeat a string

Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("*", 5) => "*****"). Other tasks related to string operations: Metrics Array length String length Copy a string Empty string (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet

#AWK

AWK

function repeat( str, n, rep, i ) { for( ; i<n; i++ ) rep = rep str return rep } BEGIN { print repeat( "ha", 5 ) }

http://rosettacode.org/wiki/Return_multiple_values

Return multiple values

Task Show how to return more than one value from a function.

#D

D

import std.stdio, std.typecons, std.algorithm; mixin template ret(string z) { mixin({ string res; auto r = z.split(" = "); auto m = r[0].split(", "); auto s = m.join("_"); res ~= "auto " ~ s ~ " = " ~ r[1] ~ ";"; foreach(i, n; m){ res ~= "auto " ~ n ~ " = " ~ s ~ "[" ~ i.to!string ~ "];\n"; } return res; }()); } auto addSub(T)(T x, T y) { return tuple(x + y, x - y); } void main() { mixin ret!q{ a, b = addSub(33, 12) }; writefln("33 + 12 = %d\n33 - 12 = %d", a, b); }