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http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation. That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange. Generic swap is a task which brings together a few separate issues in programming language semantics. Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places. Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities. Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism). Do your best!
#Rust
Rust
  fn generic_swap<'a, T>(var1: &'a mut T, var2: &'a mut T) { std::mem::swap(var1, var2) }  
http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation. That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange. Generic swap is a task which brings together a few separate issues in programming language semantics. Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places. Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities. Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism). Do your best!
#Sather
Sather
class SWAP{T} is swap(inout a, inout b:T) is t ::= a; a := b; b := t; end; end;
http://rosettacode.org/wiki/Greatest_element_of_a_list
Greatest element of a list
Task Create a function that returns the maximum value in a provided set of values, where the number of values may not be known until run-time.
#WDTE
WDTE
let s => import 'stream'; let a => import 'arrays';   let max list => a.stream list -> s.extent 1 > -> at 0  ;
http://rosettacode.org/wiki/Greatest_element_of_a_list
Greatest element of a list
Task Create a function that returns the maximum value in a provided set of values, where the number of values may not be known until run-time.
#Wortel
Wortel
@maxl [1 6 4 6 4 8 6 3] ; returns 8
http://rosettacode.org/wiki/Generator/Exponential
Generator/Exponential
A generator is an executable entity (like a function or procedure) that contains code that yields a sequence of values, one at a time, so that each time you call the generator, the next value in the sequence is provided. Generators are often built on top of coroutines or objects so that the internal state of the object is handled “naturally”. Generators are often used in situations where a sequence is potentially infinite, and where it is possible to construct the next value of the sequence with only minimal state. Task Create a function that returns a generation of the m'th powers of the positive integers starting from zero, in order, and without obvious or simple upper limit. (Any upper limit to the generator should not be stated in the source but should be down to factors such as the languages natural integer size limit or computational time/size). Use it to create a generator of:   Squares.   Cubes. Create a new generator that filters all cubes from the generator of squares. Drop the first 20 values from this last generator of filtered results, and then show the next 10 values. Note that this task requires the use of generators in the calculation of the result. Also see Generator
#C.2B.2B
C++
#include <iostream> using namespace std;   template<class T> class Generator { public: virtual T operator()() = 0; };   // Does nothing unspecialized template<class T, T P> class PowersGenerator: Generator<T> {};   // Specialize with other types, or provide a generic version of pow template<int P> class PowersGenerator<int, P>: Generator<int> { public: int i; PowersGenerator() { i = 1; } virtual int operator()() { int o = 1; for(int j = 0; j < P; ++j) o *= i; ++i; return o; } };   // Only works with non-decreasing generators template<class T, class G, class F> class Filter: Generator<T> { public: G gen; F filter; T lastG, lastF;   Filter() { lastG = gen(); lastF = filter(); }   virtual T operator()() { while(lastG >= lastF) { if(lastG == lastF) lastG = gen(); lastF = filter(); }   T out = lastG; lastG = gen(); return out; } };   int main() { Filter<int, PowersGenerator<int, 2>, PowersGenerator<int, 3>> gen;   for(int i = 0; i < 20; ++i) gen();   for(int i = 20; i < 30; ++i) cout << i << ": " << gen() << endl; }
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#Ring
Ring
  see gcd (24, 32) func gcd gcd, b while b c = gcd gcd = b b = c % b end return gcd  
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#Ruby
Ruby
  40902.gcd(24140) # => 34
http://rosettacode.org/wiki/Generate_random_chess_position
Generate random chess position
Task Generate a random chess position in FEN format. The position does not have to be realistic or even balanced,  but it must comply to the following rules: there is one and only one king of each color  (one black king and one white king); the kings must not be placed on adjacent squares; there can not be any pawn in the promotion square  (no white pawn in the eighth rank, and no black pawn in the first rank); including the kings, up to 32 pieces of either color can be placed. There is no requirement for material balance between sides. The picking of pieces does not have to comply to a regular chess set --- there can be five knights, twenty rooks, whatever ... as long as the total number of pieces do not exceed thirty-two. it is white's turn. It's assumed that both sides have lost castling rights and that there is no possibility for   en passant   (the FEN should thus end in w - - 0 1). No requirement is made regarding the probability distribution of your method, but your program should be able to span a reasonably representative sample of all possible positions. For instance, programs that would always generate positions with say five pieces on the board, or with kings on a corner, would not be considered truly random.
#Action.21
Action!
DEFINE BOARDSIZE="64" DEFINE EMPTY="'."   BYTE FUNC AbsDist(BYTE a,b) IF a>b THEN RETURN (a-b) FI RETURN (b-a)   BYTE FUNC GetPiece(BYTE ARRAY board BYTE x,y) RETURN (board(x+y*8))   PROC PutPiece(BYTE ARRAY board BYTE x,y,piece) board(x+y*8)=piece RETURN   PROC PrintBoard(BYTE ARRAY board) BYTE i,j,c   FOR j=0 TO 7 DO FOR i=0 TO 7 DO c=GetPiece(board,i,j) Put(c) OD PutE() OD RETURN   PROC Append(CHAR ARRAY s CHAR c) s(0)==+1 s(s(0))=c RETURN   PROC ExportToFen(BYTE ARRAY board CHAR ARRAY fen) CHAR ARRAY s=" w - - 0 1" INT x,y BYTE count,p   fen(0)=0 FOR y=0 TO 7 DO x=0 WHILE x<8 DO count=0 WHILE x<8 AND GetPiece(board,x,y)=EMPTY DO x==+1 count==+1 OD IF count>0 THEN Append(fen,'0+count) ELSE p=GetPiece(board,x,y) Append(fen,p) x==+1 FI OD IF y<7 THEN Append(fen,'/) FI OD   FOR x=1 TO s(0) DO Append(fen,s(x)) OD RETURN   PROC PutKings(BYTE ARRAY board) BYTE x1,y1,x2,y2 DO x1=Rand(8) y1=Rand(8) x2=Rand(8) y2=Rand(8) IF AbsDist(x1,x2)>1 AND AbsDist(y1,y2)>1 THEN PutPiece(board,x1,y1,'K) PutPiece(board,x2,y2,'k) RETURN FI OD RETURN   PROC PutPieces(BYTE ARRAY board CHAR ARRAY pieces) BYTE i,x,y,p   FOR i=1 TO pieces(0) DO p=pieces(i) DO x=Rand(8) IF p='P OR p='p THEN y=Rand(6)+1 ELSE y=Rand(8) FI UNTIL GetPiece(board,x,y)=EMPTY OD PutPiece(board,x,y,p) OD RETURN   PROC Generate(BYTE ARRAY board CHAR ARRAY pieces) SetBlock(board,BOARDSIZE,EMPTY) PutKings(board) PutPieces(board,pieces) RETURN   PROC Test(CHAR ARRAY pieces) BYTE ARRAY board(BOARDSIZE) CHAR ARRAY fen(256)   Generate(board,pieces) PrintBoard(board) ExportToFen(board,fen) PrintE(fen) PutE() RETURN   PROC Main() Test("PPPPPPPPBBNNQRRppppppppbbnnqrr") Test("PPBNQRppbnqr") RETURN
http://rosettacode.org/wiki/Generate_random_chess_position
Generate random chess position
Task Generate a random chess position in FEN format. The position does not have to be realistic or even balanced,  but it must comply to the following rules: there is one and only one king of each color  (one black king and one white king); the kings must not be placed on adjacent squares; there can not be any pawn in the promotion square  (no white pawn in the eighth rank, and no black pawn in the first rank); including the kings, up to 32 pieces of either color can be placed. There is no requirement for material balance between sides. The picking of pieces does not have to comply to a regular chess set --- there can be five knights, twenty rooks, whatever ... as long as the total number of pieces do not exceed thirty-two. it is white's turn. It's assumed that both sides have lost castling rights and that there is no possibility for   en passant   (the FEN should thus end in w - - 0 1). No requirement is made regarding the probability distribution of your method, but your program should be able to span a reasonably representative sample of all possible positions. For instance, programs that would always generate positions with say five pieces on the board, or with kings on a corner, would not be considered truly random.
#C
C
#include <stdio.h> #include <math.h> #include <string.h> #include <stdlib.h> #include <time.h>   #define TRUE 1 #define FALSE 0   typedef int bool;   char grid[8][8];   void placeKings() { int r1, r2, c1, c2; for (;;) { r1 = rand() % 8; c1 = rand() % 8; r2 = rand() % 8; c2 = rand() % 8; if (r1 != r2 && abs(r1 - r2) > 1 && abs(c1 - c2) > 1) { grid[r1][c1] = 'K'; grid[r2][c2] = 'k'; return; } } }   void placePieces(const char *pieces, bool isPawn) { int n, r, c; int numToPlace = rand() % strlen(pieces); for (n = 0; n < numToPlace; ++n) { do { r = rand() % 8; c = rand() % 8; } while (grid[r][c] != 0 || (isPawn && (r == 7 || r == 0))); grid[r][c] = pieces[n]; } }   void toFen() { char fen[80], ch; int r, c, countEmpty = 0, index = 0; for (r = 0; r < 8; ++r) { for (c = 0; c < 8; ++c) { ch = grid[r][c]; printf("%2c ", ch == 0 ? '.' : ch); if (ch == 0) { countEmpty++; } else { if (countEmpty > 0) { fen[index++] = countEmpty + 48; countEmpty = 0; } fen[index++] = ch; } } if (countEmpty > 0) { fen[index++] = countEmpty + 48; countEmpty = 0; } fen[index++]= '/'; printf("\n"); } strcpy(fen + index, " w - - 0 1"); printf("%s\n", fen); }   char *createFen() { placeKings(); placePieces("PPPPPPPP", TRUE); placePieces("pppppppp", TRUE); placePieces("RNBQBNR", FALSE); placePieces("rnbqbnr", FALSE); toFen(); }   int main() { srand(time(NULL)); createFen(); return 0; }
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#11l
11l
F genfizzbuzz(factorwords, numbers) V sfactorwords = sorted(factorwords, key' p -> p[0]) [String] lines L(num) numbers V words = sfactorwords.filter2((fact, wrd) -> (@num % fact) == 0).map2((fact, wrd) -> wrd).join(‘’) lines.append(I words != ‘’ {words} E String(num)) R lines.join("\n")   print(genfizzbuzz([(5, ‘Buzz’), (3, ‘Fizz’), (7, ‘Baxx’)], 1..20))
http://rosettacode.org/wiki/Hailstone_sequence
Hailstone sequence
The Hailstone sequence of numbers can be generated from a starting positive integer,   n   by:   If   n   is     1     then the sequence ends.   If   n   is   even then the next   n   of the sequence   = n/2   If   n   is   odd   then the next   n   of the sequence   = (3 * n) + 1 The (unproven) Collatz conjecture is that the hailstone sequence for any starting number always terminates. This sequence was named by Lothar Collatz in 1937   (or possibly in 1939),   and is also known as (the):   hailstone sequence,   hailstone numbers   3x + 2 mapping,   3n + 1 problem   Collatz sequence   Hasse's algorithm   Kakutani's problem   Syracuse algorithm,   Syracuse problem   Thwaites conjecture   Ulam's problem The hailstone sequence is also known as   hailstone numbers   (because the values are usually subject to multiple descents and ascents like hailstones in a cloud). Task Create a routine to generate the hailstone sequence for a number. Use the routine to show that the hailstone sequence for the number 27 has 112 elements starting with 27, 82, 41, 124 and ending with 8, 4, 2, 1 Show the number less than 100,000 which has the longest hailstone sequence together with that sequence's length.   (But don't show the actual sequence!) See also   xkcd (humourous).   The Notorious Collatz conjecture Terence Tao, UCLA (Presentation, pdf).   The Simplest Math Problem No One Can Solve Veritasium (video, sponsored).
#Scheme
Scheme
(define (collatz n) (if (= n 1) '(1) (cons n (collatz (if (even? n) (/ n 2) (+ 1 (* 3 n)))))))   (define (collatz-length n) (let aux ((n n) (r 1)) (if (= n 1) r (aux (if (even? n) (/ n 2) (+ 1 (* 3 n))) (+ r 1)))))   (define (collatz-max a b) (let aux ((i a) (j 0) (k 0)) (if (> i b) (list j k) (let ((h (collatz-length i))) (if (> h k) (aux (+ i 1) i h) (aux (+ i 1) j k))))))   (collatz 27) ; (27 82 41 124 62 31 94 47 142 71 214 107 322 161 484 242 121 364 182 ; 91 274 137 412 206 103 310 155 466 233 700 350 175 526 263 790 395 ; 1186 593 1780 890 445 1336 668 334 167 502 251 754 377 1132 566 283 ; 850 425 1276 638 319 958 479 1438 719 2158 1079 3238 1619 4858 2429 ; 7288 3644 1822 911 2734 1367 4102 2051 6154 3077 9232 4616 2308 1154 ; 577 1732 866 433 1300 650 325 976 488 244 122 61 184 92 46 23 70 35 ; 106 53 160 80 40 20 10 5 16 8 4 2 1)   (collatz-length 27) ; 112   (collatz-max 1 100000) ; (77031 351)
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} 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
#6502_Assembly
6502 Assembly
ASCLOW: PHA  ; push contents of registers that we TXA  ; shall be using onto the stack PHA LDA #$61  ; ASCII "a" LDX #$00 ALLOOP: STA $2000,X INX CLC ADC #$01 CMP #$7B  ; have we got beyond ASCII "z"? BNE ALLOOP LDA #$00  ; terminate the string with ASCII NUL STA $2000,X PLA  ; retrieve register contents from TAX  ; the stack PLA RTS  ; return
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} 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
#68000_Assembly
68000 Assembly
  Ascii_Low: MOVEM.L D0/A0,-(SP) ;store D0 and A0 on stack   LEA $00100000,A0 ;could also have used MOVE.L since the address is static MOVE.B #$61,D0 ;ascii "a"   loop_AsciiLow: MOVE.B D0,(A0)+ ;store letter in address and increment pointer by 1 ADDQ.B #1,D0 ;add 1 to D0 to get the next letter CMP.B #$7B,D0 ;Are we done yet? (7B is the first character after lowercase "z") BNE loop_AsciiLow ;if not, loop again MOVE.B #0,(A0) ;store the null terminator   MOVEM.L (SP)+,D0/A0 ;pop D0 and A0   rts  
http://rosettacode.org/wiki/Hello_world/Text
Hello world/Text
Hello world/Text is part of Short Circuit's Console Program Basics selection. Task Display the string Hello world! on a text console. Related tasks   Hello world/Graphical   Hello world/Line Printer   Hello world/Newbie   Hello world/Newline omission   Hello world/Standard error   Hello world/Web server
#Nanoquery
Nanoquery
println "Hello world!"
http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation. That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange. Generic swap is a task which brings together a few separate issues in programming language semantics. Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places. Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities. Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism). Do your best!
#Scala
Scala
def swap[A,B](a: A, b: B): (B, A) = (b, a)
http://rosettacode.org/wiki/Greatest_element_of_a_list
Greatest element of a list
Task Create a function that returns the maximum value in a provided set of values, where the number of values may not be known until run-time.
#Wren
Wren
var max = Fn.new { |a| a.reduce { |m, x| (x > m) ? x : m } }   var a = [42, 7, -5, 11.7, 58, 22.31, 59, -18] System.print(max.call(a))
http://rosettacode.org/wiki/Greatest_element_of_a_list
Greatest element of a list
Task Create a function that returns the maximum value in a provided set of values, where the number of values may not be known until run-time.
#XPL0
XPL0
include c:\cxpl\codes; \include 'code' declarations   def Tab=$09, LF=$0A, CR=$0D, EOF=$1A;   int CpuReg, Hand; char CmdTail($80); int I, Max, C;   [\Copy file name on command line, which is in the Program Segment Prefix (PSP) \ ES=CpuReg(11), to the CmdTail array, which is in our Data Segment = CpuReg(12) CpuReg:= GetReg; \point to copy of CPU registers Blit(CpuReg(11), $81, CpuReg(12), CmdTail, $7F); Hand:= FOpen(CmdTail, 0); \open file for input and get its handle FSet(Hand, ^I); \assign handle to device 3 OpenI(3); \initialize file for input   Max:= 0; \scan file for longest line repeat I:= 0; repeat C:= ChIn(3); case C of CR, LF, EOF: []; \don't count these characters Tab: [I:= I+8 & ~7] \(every 8th column) other I:= I+1; \count all other characters until C=LF or C=EOF; if I > Max then Max:= I; until C = EOF; Text(0, "Longest line = "); IntOut(0, Max); CrLf(0); ]
http://rosettacode.org/wiki/Generator/Exponential
Generator/Exponential
A generator is an executable entity (like a function or procedure) that contains code that yields a sequence of values, one at a time, so that each time you call the generator, the next value in the sequence is provided. Generators are often built on top of coroutines or objects so that the internal state of the object is handled “naturally”. Generators are often used in situations where a sequence is potentially infinite, and where it is possible to construct the next value of the sequence with only minimal state. Task Create a function that returns a generation of the m'th powers of the positive integers starting from zero, in order, and without obvious or simple upper limit. (Any upper limit to the generator should not be stated in the source but should be down to factors such as the languages natural integer size limit or computational time/size). Use it to create a generator of:   Squares.   Cubes. Create a new generator that filters all cubes from the generator of squares. Drop the first 20 values from this last generator of filtered results, and then show the next 10 values. Note that this task requires the use of generators in the calculation of the result. Also see Generator
#Clojure
Clojure
(defn powers [m] (for [n (iterate inc 1)] (reduce * (repeat m n))))) (def squares (powers 2)) (take 5 squares) ; => (1 4 9 16 25)
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#Run_BASIC
Run BASIC
print abs(gcd(-220,160)) function gcd(gcd,b) while b c = gcd gcd = b b = c mod b wend end function
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#Rust
Rust
extern crate num; use num::integer::gcd;
http://rosettacode.org/wiki/Generate_Chess960_starting_position
Generate Chess960 starting position
Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints: as in the standard chess game, all eight white pawns must be placed on the second rank. White pieces must stand on the first rank as in the standard game, in random column order but with the two following constraints: the bishops must be placed on opposite color squares (i.e. they must be an odd number of spaces apart or there must be an even number of spaces between them) the King must be between two rooks (with any number of other pieces between them all) Black pawns and pieces must be placed respectively on the seventh and eighth ranks, mirroring the white pawns and pieces, just as in the standard game. (That is, their positions are not independently randomized.) With those constraints there are 960 possible starting positions, thus the name of the variant. Task The purpose of this task is to write a program that can randomly generate any one of the 960 Chess960 initial positions. You will show the result as the first rank displayed with Chess symbols in Unicode: ♔♕♖♗♘ or with the letters King Queen Rook Bishop kNight.
#11l
11l
F random960() V start = [‘R’, ‘K’, ‘R’]   L(piece) [‘Q’, ‘N’, ‘N’] start.insert(random:(start.len + 1), piece)   V bishpos = random:(start.len + 1) start.insert(bishpos, Char(‘B’)) start.insert(random:(bishpos + 1), Char(‘B’)) R start   print(random960())
http://rosettacode.org/wiki/Generate_random_chess_position
Generate random chess position
Task Generate a random chess position in FEN format. The position does not have to be realistic or even balanced,  but it must comply to the following rules: there is one and only one king of each color  (one black king and one white king); the kings must not be placed on adjacent squares; there can not be any pawn in the promotion square  (no white pawn in the eighth rank, and no black pawn in the first rank); including the kings, up to 32 pieces of either color can be placed. There is no requirement for material balance between sides. The picking of pieces does not have to comply to a regular chess set --- there can be five knights, twenty rooks, whatever ... as long as the total number of pieces do not exceed thirty-two. it is white's turn. It's assumed that both sides have lost castling rights and that there is no possibility for   en passant   (the FEN should thus end in w - - 0 1). No requirement is made regarding the probability distribution of your method, but your program should be able to span a reasonably representative sample of all possible positions. For instance, programs that would always generate positions with say five pieces on the board, or with kings on a corner, would not be considered truly random.
#C.2B.2B
C++
  #include <ctime> #include <iostream> #include <string> #include <algorithm>   class chessBoard { public: void generateRNDBoard( int brds ) { int a, b, i; char c; for( int cc = 0; cc < brds; cc++ ) { memset( brd, 0, 64 ); std::string pieces = "PPPPPPPPNNBBRRQKppppppppnnbbrrqk"; random_shuffle( pieces.begin(), pieces.end() );   while( pieces.length() ) { i = rand() % pieces.length(); c = pieces.at( i ); while( true ) { a = rand() % 8; b = rand() % 8; if( brd[a][b] == 0 ) { if( c == 'P' && !b || c == 'p' && b == 7 || ( ( c == 'K' || c == 'k' ) && search( c == 'k' ? 'K' : 'k', a, b ) ) ) continue; break; } } brd[a][b] = c; pieces = pieces.substr( 0, i ) + pieces.substr( i + 1 ); } print(); } } private: bool search( char c, int a, int b ) { for( int y = -1; y < 2; y++ ) { for( int x = -1; x < 2; x++ ) { if( !x && !y ) continue; if( a + x > -1 && a + x < 8 && b + y >-1 && b + y < 8 ) { if( brd[a + x][b + y] == c ) return true; } } } return false; } void print() { int e = 0; for( int y = 0; y < 8; y++ ) { for( int x = 0; x < 8; x++ ) { if( brd[x][y] == 0 ) e++; else { if( e > 0 ) { std::cout << e; e = 0; } std::cout << brd[x][y]; } } if( e > 0 ) { std::cout << e; e = 0; } if( y < 7 ) std::cout << "/"; } std::cout << " w - - 0 1\n\n";   for( int y = 0; y < 8; y++ ) { for( int x = 0; x < 8; x++ ) { if( brd[x][y] == 0 ) std::cout << "."; else std::cout << brd[x][y]; } std::cout << "\n"; }   std::cout << "\n\n"; } char brd[8][8]; }; int main( int argc, char* argv[] ) { srand( ( unsigned )time( 0 ) ); chessBoard c; c.generateRNDBoard( 2 ); return 0; }  
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#Action.21
Action!
DEFINE MAX_NUMBERS="200" DEFINE MAX_LEN="20" DEFINE MAX_FACTORS="5" DEFINE PTR="CARD"   PROC PrintResult(BYTE max,n BYTE ARRAY factors PTR ARRAY texts) BYTE i,j,t BYTE ARRAY values(MAX_FACTORS)   FOR j=0 TO n-1 DO values(j)=1 OD   FOR i=1 TO max DO t=0 FOR j=0 TO n-1 DO IF values(j)=0 THEN t=1 Print(texts(j)) FI values(j)==+1 IF values(j)=factors(j) THEN values(j)=0 FI OD IF t=0 THEN PrintB(i) FI Put(32) OD RETURN   BYTE FUNC Find(CHAR ARRAY s CHAR c BYTE POINTER err) BYTE i   FOR i=1 TO s(0) DO IF s(i)=c THEN err^=0 RETURN (i) FI OD err^=1 RETURN (0)   PROC Main() BYTE max,i,n,pos,err BYTE ARRAY factors(MAX_FACTORS) PTR ARRAY texts(MAX_FACTORS) CHAR ARRAY s(100),tmp(100), t0(MAX_LEN),t1(MAX_LEN),t2(MAX_LEN), t3(MAX_LEN),t4(MAX_LEN)   texts(0)=t0 texts(1)=t1 texts(2)=t2 texts(3)=t3 texts(4)=t4   DO PrintF("Max number (1-%B): ",MAX_NUMBERS) max=InputB() UNTIL max>=1 AND max<=MAX_NUMBERS OD   n=0 DO PrintF("Number of rules (1-%B): ",MAX_FACTORS) n=InputB() UNTIL n>=1 AND n<=MAX_FACTORS OD   FOR i=0 TO n-1 DO DO PrintF("Rule #%B (number space text):",i+1) InputS(s) pos=Find(s,' ,@err) IF pos=1 OR pos=s(0) THEN err=1 FI IF err=0 THEN SCopyS(tmp,s,1,pos-1) factors(i)=ValB(tmp) IF factors(i)<2 THEN err=1 FI SCopyS(texts(i),s,pos+1,s(0)) FI UNTIL err=0 OD OD   PutE() PrintResult(max,n,factors,texts) RETURN
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#Ada
Ada
  with Ada.Text_IO; use Ada.Text_IO; with Ada.Integer_Text_IO; use Ada.Integer_Text_IO; with Ada.Containers.Generic_Array_Sort; with Ada.Strings.Unbounded; use Ada.Strings.Unbounded; with Ada.Text_IO.Unbounded_IO; use Ada.Text_IO.Unbounded_IO;   procedure Main is type map_element is record Num  : Positive; Word : Unbounded_String; end record;   type map_list is array (Positive range <>) of map_element;   function "<" (Left, Right : map_element) return Boolean is begin return Left.Num < Right.Num; end "<";   procedure list_sort is new Ada.Containers.Generic_Array_Sort (Index_Type => Positive, Element_Type => map_element, Array_Type => map_list);   procedure general_fizz_buzz (max : Positive; words : in out map_list) is found : Boolean; begin list_sort (words);   for i in 1 .. max loop found := False; for element of words loop if i mod element.Num = 0 then found := True; Put (element.Word); end if; end loop; if not found then Put (Item => i, Width => 1); end if; New_Line; end loop; end general_fizz_buzz;   fizzy : map_list := ((3, To_Unbounded_String ("FIZZ")), (7, To_Unbounded_String ("BAXX")), (5, To_Unbounded_String ("BUZZ")));   begin general_fizz_buzz (20, fizzy); end Main;  
http://rosettacode.org/wiki/Hailstone_sequence
Hailstone sequence
The Hailstone sequence of numbers can be generated from a starting positive integer,   n   by:   If   n   is     1     then the sequence ends.   If   n   is   even then the next   n   of the sequence   = n/2   If   n   is   odd   then the next   n   of the sequence   = (3 * n) + 1 The (unproven) Collatz conjecture is that the hailstone sequence for any starting number always terminates. This sequence was named by Lothar Collatz in 1937   (or possibly in 1939),   and is also known as (the):   hailstone sequence,   hailstone numbers   3x + 2 mapping,   3n + 1 problem   Collatz sequence   Hasse's algorithm   Kakutani's problem   Syracuse algorithm,   Syracuse problem   Thwaites conjecture   Ulam's problem The hailstone sequence is also known as   hailstone numbers   (because the values are usually subject to multiple descents and ascents like hailstones in a cloud). Task Create a routine to generate the hailstone sequence for a number. Use the routine to show that the hailstone sequence for the number 27 has 112 elements starting with 27, 82, 41, 124 and ending with 8, 4, 2, 1 Show the number less than 100,000 which has the longest hailstone sequence together with that sequence's length.   (But don't show the actual sequence!) See also   xkcd (humourous).   The Notorious Collatz conjecture Terence Tao, UCLA (Presentation, pdf).   The Simplest Math Problem No One Can Solve Veritasium (video, sponsored).
#Scilab
Scilab
function x=hailstone(n) // iterative definition // usage: global verbose; verbose=%T; hailstone(27) global verbose x=0; loop=%T while(loop) x=x+1 if verbose then printf('%i ',n) end if n==1 then loop=%F elseif modulo(n,2)==1 then n=3*n+1 else n=n/2 end end endfunction   global verbose; verbose=1; N=hailstone(27); printf('\n\n%i\n',N);   global verbose; verbose=0; N=100000; M=zeros(N,1); for k=1:N M(k)=hailstone(k); end; [maxLength,n]=max(M)
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} 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
#8080_Assembly
8080 Assembly
org 100h jmp test   ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; Store the lowercase alphabet as a CP/M string ;; ($-terminated), starting at HL. ;; Destroys: b, c   alph: lxi b,611ah ; set B='a' and C=26 (counter) aloop: mov m,b ; store letter in memory inr b ; next letter inx h ; next memory position dcr c ; one fewer letter left jnz aloop ; go do the next letter if there is one mvi m,'$' ; terminate the string ret   ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; Test code test: lxi h,buf ; select buffer call alph ; generate alphabet   lxi d,buf ; print string in buffer mvi c,9 call 5 rst 0     buf: ds 27 ; buffer to keep the alphabet in  
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} 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
#8086_Assembly
8086 Assembly
bits 16 cpu 8086 org 100h section .text jmp demo ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;; Store the lowercase alphabet starting at [ES:DI] ;;; Destroys AX, CX, DI alph: mov cx,13 ; 2*13 words = 26 bytes mov ax,'ab' ; Do two bytes at once .loop: stosw ; Store AX at ES:DI and add 2 to DI add ax,202h ; Add 2 to both bytes (CD, EF, ...) loop .loop mov al,'$' ; MS-DOS string terminator stosb ret ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; demo: mov di,buf ; Pointer to buffer call alph ; Generate the alphabet mov dx,buf ; Print the contents of the buffer mov ah,9 int 21h ret section .bss buf: resb 27 ; Buffer to store the alphabet in
http://rosettacode.org/wiki/Hello_world/Text
Hello world/Text
Hello world/Text is part of Short Circuit's Console Program Basics selection. Task Display the string Hello world! on a text console. Related tasks   Hello world/Graphical   Hello world/Line Printer   Hello world/Newbie   Hello world/Newline omission   Hello world/Standard error   Hello world/Web server
#Neat
Neat
void main() writeln "Hello world!";
http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation. That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange. Generic swap is a task which brings together a few separate issues in programming language semantics. Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places. Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities. Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism). Do your best!
#Scheme
Scheme
; swap elements of a vector ; vector-swap! is not part of r5rs, so we define it (define (vector-swap! v i j) (let ((a (vector-ref v i)) (b (vector-ref v j))) (vector-set! v i b) (vector-set! v j a)))   (let ((vec (vector 1 2 3 4 5))) (vector-swap! vec 0 4) vec) ; #(5 2 3 4 1)     ; we can swap also in lists (define (list-swap! v i j) (let* ((x (list-tail v i)) (y (list-tail v j)) (a (car x)) (b (car y))) (set-car! x b) (set-car! y a)))   (let ((lis (list 1 2 3 4 5))) (list-swap! lis 0 4) lis) ; (5 2 3 4 1)     ; using macros (will work on variables, not on vectors or lists) (define-syntax swap! (syntax-rules () ((_ a b) (let ((tmp a)) (set! a b) (set! b tmp)))))   ; try it (let ((a 1) (b 2)) (swap! a b) (list a b)) ; (2 1)
http://rosettacode.org/wiki/Greatest_element_of_a_list
Greatest element of a list
Task Create a function that returns the maximum value in a provided set of values, where the number of values may not be known until run-time.
#XSLT
XSLT
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"> <xsl:output method="text"/>   <xsl:template match="/"> <xsl:for-each select="/*/*"> <!-- without data-type="number", items are sorted alphabetically --> <xsl:sort data-type="number" order="descending"/> <xsl:if test="position() = 1"> <xsl:value-of select="."/> </xsl:if> </xsl:for-each> </xsl:template> </xsl:stylesheet>
http://rosettacode.org/wiki/Generator/Exponential
Generator/Exponential
A generator is an executable entity (like a function or procedure) that contains code that yields a sequence of values, one at a time, so that each time you call the generator, the next value in the sequence is provided. Generators are often built on top of coroutines or objects so that the internal state of the object is handled “naturally”. Generators are often used in situations where a sequence is potentially infinite, and where it is possible to construct the next value of the sequence with only minimal state. Task Create a function that returns a generation of the m'th powers of the positive integers starting from zero, in order, and without obvious or simple upper limit. (Any upper limit to the generator should not be stated in the source but should be down to factors such as the languages natural integer size limit or computational time/size). Use it to create a generator of:   Squares.   Cubes. Create a new generator that filters all cubes from the generator of squares. Drop the first 20 values from this last generator of filtered results, and then show the next 10 values. Note that this task requires the use of generators in the calculation of the result. Also see Generator
#Common_Lisp
Common Lisp
(defun take (seq &optional (n 1)) (values-list (loop repeat n collect (funcall seq))))   (defun power-seq (n) (let ((x 0)) (lambda () (expt (incf x) n))))   (defun filter-seq (s1 s2) ;; remove s2 from s1 (let ((x1 (take s1)) (x2 (take s2))) (lambda () (tagbody g (if (= x1 x2) (progn (setf x1 (take s1) x2 (take s2)) (go g))) (if (> x1 x2) (progn (setf x2 (take s2)) (go g))))   (prog1 x1 (setf x1 (take s1))))))   (let ((2not3 (filter-seq (power-seq 2) (power-seq 3)))) (take 2not3 20) ;; drop 20 (princ (multiple-value-list (take 2not3 10))))
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#Sass.2FSCSS
Sass/SCSS
  @function gcd($a,$b) { @while $b > 0 { $c: $a % $b; $a: $b; $b: $c; } @return $a; }  
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#Sather
Sather
class MATH is   gcd_iter(u, v:INT):INT is loop while!( v.bool ); t ::= u; u := v; v := t % v; end; return u.abs; end;   gcd(u, v:INT):INT is if v.bool then return gcd(v, u%v); end; return u.abs; end;     private swap(inout a, inout b:INT) is t ::= a; a := b; b := t; end;   gcd_bin(u, v:INT):INT is t:INT;   u := u.abs; v := v.abs; if u < v then swap(inout u, inout v); end; if v = 0 then return u; end; k ::= 1; loop while!( u.is_even and v.is_even ); u := u / 2; v := v / 2; k := k * 2; end; if u.is_even then t := -v; else t := u; end; loop while!( t.bool ); loop while!( t.is_even ); t := t / 2; end; if t > 0 then u := t; else v := -t; end; t := u - v; end; return u * k; end;   end;
http://rosettacode.org/wiki/Generate_Chess960_starting_position
Generate Chess960 starting position
Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints: as in the standard chess game, all eight white pawns must be placed on the second rank. White pieces must stand on the first rank as in the standard game, in random column order but with the two following constraints: the bishops must be placed on opposite color squares (i.e. they must be an odd number of spaces apart or there must be an even number of spaces between them) the King must be between two rooks (with any number of other pieces between them all) Black pawns and pieces must be placed respectively on the seventh and eighth ranks, mirroring the white pawns and pieces, just as in the standard game. (That is, their positions are not independently randomized.) With those constraints there are 960 possible starting positions, thus the name of the variant. Task The purpose of this task is to write a program that can randomly generate any one of the 960 Chess960 initial positions. You will show the result as the first rank displayed with Chess symbols in Unicode: ♔♕♖♗♘ or with the letters King Queen Rook Bishop kNight.
#Action.21
Action!
DEFINE MAX_NUMBERS="200" DEFINE MAX_LEN="20" DEFINE MAX_FACTORS="5" DEFINE PTR="CARD"   PROC PrintResult(BYTE max,n BYTE ARRAY factors PTR ARRAY texts) BYTE i,j,t BYTE ARRAY values(MAX_FACTORS)   FOR j=0 TO n-1 DO values(j)=1 OD   FOR i=1 TO max DO t=0 FOR j=0 TO n-1 DO IF values(j)=0 THEN t=1 Print(texts(j)) FI values(j)==+1 IF values(j)=factors(j) THEN values(j)=0 FI OD IF t=0 THEN PrintB(i) FI Put(32) OD RETURN   BYTE FUNC Find(CHAR ARRAY s CHAR c BYTE POINTER err) BYTE i   FOR i=1 TO s(0) DO IF s(i)=c THEN err^=0 RETURN (i) FI OD err^=1 RETURN (0)   PROC Main() BYTE max,i,n,pos,err BYTE ARRAY factors(MAX_FACTORS) PTR ARRAY texts(MAX_FACTORS) CHAR ARRAY s(100),tmp(100), t0(MAX_LEN),t1(MAX_LEN),t2(MAX_LEN), t3(MAX_LEN),t4(MAX_LEN)   texts(0)=t0 texts(1)=t1 texts(2)=t2 texts(3)=t3 texts(4)=t4   DO PrintF("Max number (1-%B): ",MAX_NUMBERS) max=InputB() UNTIL max>=1 AND max<=MAX_NUMBERS OD   n=0 DO PrintF("Number of rules (1-%B): ",MAX_FACTORS) n=InputB() UNTIL n>=1 AND n<=MAX_FACTORS OD   FOR i=0 TO n-1 DO DO PrintF("Rule #%B (number space text):",i+1) InputS(s) pos=Find(s,' ,@err) IF pos=1 OR pos=s(0) THEN err=1 FI IF err=0 THEN SCopyS(tmp,s,1,pos-1) factors(i)=ValB(tmp) IF factors(i)<2 THEN err=1 FI SCopyS(texts(i),s,pos+1,s(0)) FI UNTIL err=0 OD OD   PutE() PrintResult(max,n,factors,texts) RETURN
http://rosettacode.org/wiki/Generate_Chess960_starting_position
Generate Chess960 starting position
Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints: as in the standard chess game, all eight white pawns must be placed on the second rank. White pieces must stand on the first rank as in the standard game, in random column order but with the two following constraints: the bishops must be placed on opposite color squares (i.e. they must be an odd number of spaces apart or there must be an even number of spaces between them) the King must be between two rooks (with any number of other pieces between them all) Black pawns and pieces must be placed respectively on the seventh and eighth ranks, mirroring the white pawns and pieces, just as in the standard game. (That is, their positions are not independently randomized.) With those constraints there are 960 possible starting positions, thus the name of the variant. Task The purpose of this task is to write a program that can randomly generate any one of the 960 Chess960 initial positions. You will show the result as the first rank displayed with Chess symbols in Unicode: ♔♕♖♗♘ or with the letters King Queen Rook Bishop kNight.
#AutoHotkey
AutoHotkey
Loop, 5 Out .= Chess960() "`n" MsgBox, % RTrim(Out, "`n")   Chess960() { P := {} P[K := Rand(2, 7)] := Chr(0x2654) ; King P[Rand(1, K - 1)] := Chr(0x2656) ; Rook 1 P[Rand(K + 1, 8)] := Chr(0x2656) ; Rook 2 Loop, 8 Remaining .= P[A_Index] ? "" : A_Index "`n" Sort, Remaining, Random N P[Bishop1 := SubStr(Remaining, 1, 1)] := Chr(0x2657) ; Bishop 1 Remaining := SubStr(Remaining, 3) Loop, Parse, Remaining, `n if (Mod(Bishop1 - A_LoopField, 2)) Odd .= A_LoopField "`n" else Even .= A_LoopField "`n" X := StrSplit(Odd Even, "`n") P[X.1] := Chr(0x2657) ; Bishop 2 P[X.2] := Chr(0x2655) ; Queen P[X.3] := Chr(0x2658) ; Knight 1 P[X.4] := Chr(0x2658) ; Knight 2 for Key, Val in P Out .= Val return Out }   Rand(Min, Max) { Random, n, Min, Max return n }
http://rosettacode.org/wiki/Generate_random_chess_position
Generate random chess position
Task Generate a random chess position in FEN format. The position does not have to be realistic or even balanced,  but it must comply to the following rules: there is one and only one king of each color  (one black king and one white king); the kings must not be placed on adjacent squares; there can not be any pawn in the promotion square  (no white pawn in the eighth rank, and no black pawn in the first rank); including the kings, up to 32 pieces of either color can be placed. There is no requirement for material balance between sides. The picking of pieces does not have to comply to a regular chess set --- there can be five knights, twenty rooks, whatever ... as long as the total number of pieces do not exceed thirty-two. it is white's turn. It's assumed that both sides have lost castling rights and that there is no possibility for   en passant   (the FEN should thus end in w - - 0 1). No requirement is made regarding the probability distribution of your method, but your program should be able to span a reasonably representative sample of all possible positions. For instance, programs that would always generate positions with say five pieces on the board, or with kings on a corner, would not be considered truly random.
#Crystal
Crystal
def hasNK(board, a, b) (-1..1).each do |g| (-1..1).each do |f| aa = a + f; bb = b + g if (0..7).includes?(aa) && (0..7).includes?(bb) p = board[aa + 8 * bb] return true if p == "K" || p == "k" end end end return false end   def generateBoard(board, pieces) pieces.each_char do |p| while true a = rand(8); b = rand(8) next if ( (b == 0 || b == 7) && (p == "P" || p == "p") ) || ( (p == "k" || p == "K") && hasNK(board, a, b) ) break if board[a + b * 8] == '.' end board[a + b * 8] = p end end   pieces = "ppppppppkqrrbbnnPPPPPPPPKQRRBBNN" 11.times do e = pieces.size - 1 while e > 0 p = rand(e); t = pieces[e] #pieces[e] = pieces[p]; pieces[p] = t; e -= 1 # in Ruby pieces = pieces.sub(e, pieces[p]) # in Crystal because pieces = pieces.sub(p, t); e -= 1 # strings immutable end end   # No 'nil' for Crystal arrays; use '.' for blank value board = Array.new(64, '.'); generateBoard(board, pieces) puts e = 0 8.times do |j| row_j = j * 8 8.times do |i| board[row_j + i ] == '.' ? (e += 1) : ( (print(e); e = 0) if e > 0 print board[row_j + i] ) end (print(e); e = 0) if e > 0 print("/") if j < 7 end   print(" w - - 0 1\n") 8.times do |j| row_j = j * 8 8.times { |i| board[row_j + i] == '.' ? print(".") : print(board[row_j + i]) } puts end   # Simpler for same output 8.times{ |row| puts board[row*8..row*8 + 7].join("") }
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#ALGOL_68
ALGOL 68
BEGIN # generalised FizzBuzz # # prompts for an integer, reads it and returns it # PROC read integer = ( STRING prompt )INT: BEGIN print( ( prompt ) ); INT result; read( ( result, newline ) ); result END; # read integer # # prompts for a string, reads it and returns it # PROC read string = ( STRING prompt )STRING: BEGIN print( ( prompt ) ); STRING result; read( ( result, newline ) ); result END; # read string # # mode to hold a factor and associated text # MODE FBFACTOR = STRUCT( INT factor, STRING text ); #===============================================================# # quicksort routine for the factors, from the Algol 68 uicksort # # task sample # #---------------------------------------------------------------# #--- Swap function ---# PROC swap = (REF[]FBFACTOR array, INT first, INT second) VOID: ( FBFACTOR temp = array[first]; array[first] := array[second]; array[second] := temp ); #--- Quick sort 3 arg function ---# PROC quick = (REF[]FBFACTOR array, INT first, INT last) VOID: ( INT smaller := first + 1, larger := last; FBFACTOR pivot := array[first]; WHILE smaller <= larger DO WHILE array[smaller] < pivot AND smaller < last DO smaller +:= 1 OD; WHILE array[larger] > pivot AND larger > first DO larger -:= 1 OD; IF smaller < larger THEN swap(array, smaller, larger); smaller +:= 1; larger -:= 1 ELSE smaller +:= 1 FI OD; swap(array, first, larger); IF first < larger -1 THEN quick(array, first, larger-1) FI; IF last > larger +1 THEN quick(array, larger+1, last) FI ); # comparison operators # OP < = ( FBFACTOR a, b )BOOL: factor OF a < factor OF b; OP > = ( FBFACTOR a, b )BOOL: factor OF a > factor OF b; #===============================================================# # get the maximum number to consider # INT max number = read integer( "Numbers reuired: " ); # number of factors reuired # INT max factor = 3; # get the factors and associated words # [ max factor ]FBFACTOR factors; FOR i TO max factor DO factor OF factors[ i ] := read integer( "Factor " + whole( i, 0 ) + ": " ); text OF factors [ i ] := read string( "Text for " + whole( factor OF factors[ i ], 0 ) + ": " ) OD; # sort the factors into order # quick( factors, 1, UPB factors ); # play the game # FOR n TO max number DO STRING text := ""; FOR factor TO max factor DO IF n MOD factor OF factors[ factor ] = 0 THEN text +:= text OF factors[ factor ] FI OD; IF text = "" THEN # no words applicable to n, just show the digits # text := whole( n, 0 ) FI; print( ( text, newline ) ) OD END
http://rosettacode.org/wiki/Hailstone_sequence
Hailstone sequence
The Hailstone sequence of numbers can be generated from a starting positive integer,   n   by:   If   n   is     1     then the sequence ends.   If   n   is   even then the next   n   of the sequence   = n/2   If   n   is   odd   then the next   n   of the sequence   = (3 * n) + 1 The (unproven) Collatz conjecture is that the hailstone sequence for any starting number always terminates. This sequence was named by Lothar Collatz in 1937   (or possibly in 1939),   and is also known as (the):   hailstone sequence,   hailstone numbers   3x + 2 mapping,   3n + 1 problem   Collatz sequence   Hasse's algorithm   Kakutani's problem   Syracuse algorithm,   Syracuse problem   Thwaites conjecture   Ulam's problem The hailstone sequence is also known as   hailstone numbers   (because the values are usually subject to multiple descents and ascents like hailstones in a cloud). Task Create a routine to generate the hailstone sequence for a number. Use the routine to show that the hailstone sequence for the number 27 has 112 elements starting with 27, 82, 41, 124 and ending with 8, 4, 2, 1 Show the number less than 100,000 which has the longest hailstone sequence together with that sequence's length.   (But don't show the actual sequence!) See also   xkcd (humourous).   The Notorious Collatz conjecture Terence Tao, UCLA (Presentation, pdf).   The Simplest Math Problem No One Can Solve Veritasium (video, sponsored).
#Seed7
Seed7
$ include "seed7_05.s7i";   const func array integer: hailstone (in var integer: n) is func result var array integer: hSequence is 0 times 0; begin while n <> 1 do hSequence &:= n; if odd(n) then n := 3 * n + 1; else n := n div 2; end if; end while; hSequence &:= n; end func;   const func integer: hailstoneSequenceLength (in var integer: n) is func result var integer: sequenceLength is 1; begin while n <> 1 do incr(sequenceLength); if odd(n) then n := 3 * n + 1; else n := n div 2; end if; end while; end func;   const proc: main is func local var integer: number is 0; var integer: length is 0; var integer: maxLength is 0; var integer: numberOfMaxLength is 0; var array integer: h27 is 0 times 0; begin for number range 1 to 99999 do length := hailstoneSequenceLength(number); if length > maxLength then maxLength := length; numberOfMaxLength := number; end if; end for; h27 := hailstone(27); writeln("hailstone(27):"); for number range 1 to 4 do write(h27[number] <& ", "); end for; write("...."); for number range length(h27) -3 to length(h27) do write(", " <& h27[number]); end for; writeln(" length=" <& length(h27)); writeln("Maximum length " <& maxLength <& " at number=" <& numberOfMaxLength); end func;
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} 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
  "" ( 'a n:+ s:+ ) 0 25 loop . cr  
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} 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
#ABAP
ABAP
REPORT lower_case_ascii.   WRITE: / to_lower( sy-abcde ).
http://rosettacode.org/wiki/Hello_world/Text
Hello world/Text
Hello world/Text is part of Short Circuit's Console Program Basics selection. Task Display the string Hello world! on a text console. Related tasks   Hello world/Graphical   Hello world/Line Printer   Hello world/Newbie   Hello world/Newline omission   Hello world/Standard error   Hello world/Web server
#Neko
Neko
$print("Hello world!");
http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation. That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange. Generic swap is a task which brings together a few separate issues in programming language semantics. Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places. Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities. Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism). Do your best!
#Seed7
Seed7
const proc: generate_swap (in type: aType) is func begin   const proc: swap (inout aType: left, inout aType: right) is func local var aType: temp is aType.value; begin temp := left; left := right; right := temp; end func;   end func;
http://rosettacode.org/wiki/Greatest_element_of_a_list
Greatest element of a list
Task Create a function that returns the maximum value in a provided set of values, where the number of values may not be known until run-time.
#Yabasic
Yabasic
l$ = "1,1234,62,234,12,34,6"   dim n$(1)   n = token(l$, n$(), ", ")   for i = 1 to n t$ = n$(i) if t$ > m$ then m$ = t$ end if // or: if t$ > m$ m$ = t$ if val(t$) > m then m = val(t$) end if // or: if val(t$) > m m = val(t$) next   print "Alphabetic order: ", m$, ", numeric order: ", m
http://rosettacode.org/wiki/Greatest_element_of_a_list
Greatest element of a list
Task Create a function that returns the maximum value in a provided set of values, where the number of values may not be known until run-time.
#Yacas
Yacas
Max({1, 3, 3, 7}) Max({Pi,Exp(1)+2/5,17*Cos(6)/5,Sqrt(91/10)}) Max({1,6,Infinity}) Max({})
http://rosettacode.org/wiki/Generator/Exponential
Generator/Exponential
A generator is an executable entity (like a function or procedure) that contains code that yields a sequence of values, one at a time, so that each time you call the generator, the next value in the sequence is provided. Generators are often built on top of coroutines or objects so that the internal state of the object is handled “naturally”. Generators are often used in situations where a sequence is potentially infinite, and where it is possible to construct the next value of the sequence with only minimal state. Task Create a function that returns a generation of the m'th powers of the positive integers starting from zero, in order, and without obvious or simple upper limit. (Any upper limit to the generator should not be stated in the source but should be down to factors such as the languages natural integer size limit or computational time/size). Use it to create a generator of:   Squares.   Cubes. Create a new generator that filters all cubes from the generator of squares. Drop the first 20 values from this last generator of filtered results, and then show the next 10 values. Note that this task requires the use of generators in the calculation of the result. Also see Generator
#D
D
void main() { import std.stdio, std.bigint, std.range, std.algorithm;   auto squares = 0.sequence!"n".map!(i => i.BigInt ^^ 2); auto cubes = 0.sequence!"n".map!(i => i.BigInt ^^ 3);   squares.setDifference(cubes).drop(20).take(10).writeln; }
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#S-BASIC
S-BASIC
  rem - return p mod q function mod(p, q = integer) = integer end = p - q * (p / q)   rem - return greatest common divisor of x and y function gcd(x, y = integer) = integer var r, temp = integer if x < y then begin temp = x x = y y = temp end r = mod(x, y) while r <> 0 do begin x = y y = r r = mod(x, y) end end = y   rem - exercise the function   print "The GCD of 21 and 35 is"; gcd(21,35) print "The GCD of 23 and 35 is"; gcd(23,35) print "The GCD of 1071 and 1029 is"; gcd(1071, 1029) print "The GCD of 3528 and 3780 is"; gcd(3528,3780)   end  
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#Scala
Scala
def gcd(a: Int, b: Int): Int = if (b == 0) a.abs else gcd(b, a % b)
http://rosettacode.org/wiki/Generate_Chess960_starting_position
Generate Chess960 starting position
Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints: as in the standard chess game, all eight white pawns must be placed on the second rank. White pieces must stand on the first rank as in the standard game, in random column order but with the two following constraints: the bishops must be placed on opposite color squares (i.e. they must be an odd number of spaces apart or there must be an even number of spaces between them) the King must be between two rooks (with any number of other pieces between them all) Black pawns and pieces must be placed respectively on the seventh and eighth ranks, mirroring the white pawns and pieces, just as in the standard game. (That is, their positions are not independently randomized.) With those constraints there are 960 possible starting positions, thus the name of the variant. Task The purpose of this task is to write a program that can randomly generate any one of the 960 Chess960 initial positions. You will show the result as the first rank displayed with Chess symbols in Unicode: ♔♕♖♗♘ or with the letters King Queen Rook Bishop kNight.
#BASIC
BASIC
for i = 1 to 10 inicio$ = "RKR" pieza$ = "QNN"   for n = 1 to length(pieza$) posic = int(rand*(length(inicio$) + 1)) + 1 inicio$ = left(inicio$, posic-1) + mid(pieza$, n, 1) + right(inicio$, length(inicio$) - posic + 1) next n posic = int(rand*(length(inicio$) + 1)) + 1 inicio$ = left(inicio$, posic-1) + "B" + right(inicio$, length(inicio$) - posic + 1) posic += 1 + 2 * int(int(rand*(length(inicio$) - posic)) / 2) inicio$ = left(inicio$, posic-1) + "B" + right(inicio$, length(inicio$) - posic + 1) print inicio$ next i end
http://rosettacode.org/wiki/Generate_Chess960_starting_position
Generate Chess960 starting position
Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints: as in the standard chess game, all eight white pawns must be placed on the second rank. White pieces must stand on the first rank as in the standard game, in random column order but with the two following constraints: the bishops must be placed on opposite color squares (i.e. they must be an odd number of spaces apart or there must be an even number of spaces between them) the King must be between two rooks (with any number of other pieces between them all) Black pawns and pieces must be placed respectively on the seventh and eighth ranks, mirroring the white pawns and pieces, just as in the standard game. (That is, their positions are not independently randomized.) With those constraints there are 960 possible starting positions, thus the name of the variant. Task The purpose of this task is to write a program that can randomly generate any one of the 960 Chess960 initial positions. You will show the result as the first rank displayed with Chess symbols in Unicode: ♔♕♖♗♘ or with the letters King Queen Rook Bishop kNight.
#Befunge
Befunge
#.#.#.#.065*0#v_1-\>>?1v v,":".:%*8"x"$<^!:\*2<+< >48*,:4%2*1#v+#02#\3#g<< v"B"*2%4:/4p<vg0:+1<\-1< >\0p4/:6%0:0g>68*`#^_\:| v"RKRNN"p11/6$p0\ "Q" \< >"NRNKRRNNKRNRKNRRNKNR"v v"NRNKRNRKNRNRKRNRNNKR"< >"RKRNN"11g:!#v_\$\$\$\v v _v#!`*86:g0:<^!:-1$\$< >$\>,1+ :7`#@_^> v960v <
http://rosettacode.org/wiki/Generate_random_chess_position
Generate random chess position
Task Generate a random chess position in FEN format. The position does not have to be realistic or even balanced,  but it must comply to the following rules: there is one and only one king of each color  (one black king and one white king); the kings must not be placed on adjacent squares; there can not be any pawn in the promotion square  (no white pawn in the eighth rank, and no black pawn in the first rank); including the kings, up to 32 pieces of either color can be placed. There is no requirement for material balance between sides. The picking of pieces does not have to comply to a regular chess set --- there can be five knights, twenty rooks, whatever ... as long as the total number of pieces do not exceed thirty-two. it is white's turn. It's assumed that both sides have lost castling rights and that there is no possibility for   en passant   (the FEN should thus end in w - - 0 1). No requirement is made regarding the probability distribution of your method, but your program should be able to span a reasonably representative sample of all possible positions. For instance, programs that would always generate positions with say five pieces on the board, or with kings on a corner, would not be considered truly random.
#Factor
Factor
USING: combinators.short-circuit grouping io kernel math math.parser math.ranges math.vectors prettyprint random sequences sets splitting.monotonic strings ; IN: rosetta-code.random-chess-position   <PRIVATE   CONSTANT: pieces "RNBQBNRPPPPPPPPrnbqbnrpppppppp" CONSTANT: empty CHAR: .   : <empty-board> ( -- seq ) 64 [ empty ] "" replicate-as ; : empty-index ( seq -- n ) empty swap indices random ; : place ( seq elt n -- seq' ) rot [ set-nth ] keep ;   ! return a list of indices that are adjacent to n : adj ( n -- seq ) [ 1 - ] [ 1 + ] bi [a,b] { 8 8 8 } [ v- ] 2keep dupd v+ append append ;   : rand-non-adjacent ( m -- n ) 64 <iota> swap adj diff random ;   : place-kings ( seq -- seq' ) CHAR: K over empty-index [ place ] keep [ CHAR: k ] dip rand-non-adjacent place ;   : non-pawn ( seq elt -- seq' ) over empty-index place ;   ! prevent placing of pawns in ranks 1 and 8 : pawn ( seq elt -- seq' ) over empty swap indices [ { [ 7 > ] [ 56 < ] } 1&& ] filter random place ;   : place-piece ( seq -- seq' ) pieces random dup "Pp" member? [ pawn ] [ non-pawn ] if ;   PRIVATE>     : position ( -- seq ) <empty-board> place-kings 30 random [ place-piece ] times ;   : position. ( seq -- ) [ 1string ] { } map-as 8 group simple-table. ;   : position>fen ( seq -- seq' ) 8 group [ [ = ] monotonic-split [ dup first empty = [ length number>string ] when ] map concat ] map "/" join "/ w - - 0 1" append ;   : random-chess-position-demo ( -- ) position [ position. ] [ position>fen print ] bi ;   MAIN: random-chess-position-demo
http://rosettacode.org/wiki/Generate_random_chess_position
Generate random chess position
Task Generate a random chess position in FEN format. The position does not have to be realistic or even balanced,  but it must comply to the following rules: there is one and only one king of each color  (one black king and one white king); the kings must not be placed on adjacent squares; there can not be any pawn in the promotion square  (no white pawn in the eighth rank, and no black pawn in the first rank); including the kings, up to 32 pieces of either color can be placed. There is no requirement for material balance between sides. The picking of pieces does not have to comply to a regular chess set --- there can be five knights, twenty rooks, whatever ... as long as the total number of pieces do not exceed thirty-two. it is white's turn. It's assumed that both sides have lost castling rights and that there is no possibility for   en passant   (the FEN should thus end in w - - 0 1). No requirement is made regarding the probability distribution of your method, but your program should be able to span a reasonably representative sample of all possible positions. For instance, programs that would always generate positions with say five pieces on the board, or with kings on a corner, would not be considered truly random.
#FreeBASIC
FreeBASIC
  Dim Shared As Byte grid(8, 8), r, c   Sub placeKings() Dim As Byte r1, r2, c1, c2   Do r1 = Int(Rnd*8) c1 = Int(Rnd*8) r2 = Int(Rnd*8) c2 = Int(Rnd*8) If (r1 <> r2 And Abs(r1 - r2) > 1 And Abs(c1 - c2) > 1) Then grid(r1, c1) = Asc("K") grid(r2, c2) = Asc("k") Return End If Loop End Sub   Sub placePieces(pieces As String, isPawn As Byte) Dim numToPlace As Byte = Int(Rnd*(Len(pieces)))   For n As Byte = 0 To numToPlace-1 Do r = Int(Rnd*8) c = Int(Rnd*8) Loop Until(Not(grid(r, c) Or (isPawn And (r = 7 Or r = 0)))) grid(r, c) = Asc(Mid(pieces, n, 1)) Next n End Sub   Sub toFen() Dim As Byte ch, countEmpty = 0 Dim As String fen   For r = 0 To 8-1 For c = 0 To 8-1 ch = grid(r, c) If ch <> 0 Then Print " " & Chr(ch); Else Print " ."; End If If ch = 0 Then countEmpty += 1 Else If countEmpty > 0 Then fen += Chr(countEmpty + 48) countEmpty = 0 End If fen += Chr(ch) End If Next c If countEmpty > 0 Then fen += Chr(countEmpty + 48) countEmpty = 0 End If fen += "/" Print Next r fen += " w - - 0 1" Print fen End Sub   Randomize Timer placeKings() placePieces("PPPPPPPP", True) placePieces("pppppppp", True) placePieces("RNBQBNR", False) placePieces("rnbqbnr", False) toFen() Sleep  
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#AppleScript
AppleScript
--------------------- GENERAL FIZZBUZZ -------------------   -- fizzEtc :: [(Int, String)] -> [Symbol] on fizzEtc(rules) -- A non-finite sequence of fizzEtc symbols, -- as defined by the given list of rules. script numberOrNoise on |λ|(n) script ruleMatch on |λ|(a, mk) set {m, k} to mk   if 0 = (n mod m) then if integer is class of a then k else a & k end if else a end if end |λ| end script   foldl(ruleMatch, n, rules) end |λ| end script   fmapGen(numberOrNoise, enumFrom(1)) end fizzEtc     --------------------------- TEST ------------------------- on run   unlines(take(20, ¬ fizzEtc({{3, "Fizz"}, {5, "Buzz"}, {7, "Baxx"}})))   end run     ------------------------- GENERIC ------------------------   -- enumFrom :: Enum a => a -> [a] on enumFrom(x) script property v : missing value on |λ|() if missing value is not v then set v to 1 + v else set v to x end if return v end |λ| end script end enumFrom     -- fmapGen <$> :: (a -> b) -> Gen [a] -> Gen [b] on fmapGen(f, gen) script property g : mReturn(f) on |λ|() set v to gen's |λ|() if v is missing value then v else g's |λ|(v) end if end |λ| end script end fmapGen     -- 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     -- mReturn :: First-class m => (a -> b) -> m (a -> b) on mReturn(f) -- 2nd class handler function lifted into 1st class script wrapper. if script is class of f then f else script property |λ| : f end script end if end mReturn     -- take :: Int -> [a] -> [a] -- take :: Int -> String -> String on take(n, xs) set ys to {} repeat with i from 1 to n set v to |λ|() of xs if missing value is v then return ys else set end of ys to v end if end repeat return ys end take     -- unlines :: [String] -> String on unlines(xs) -- A single string formed by the intercalation -- of a list of strings with the newline character. set {dlm, my text item delimiters} to ¬ {my text item delimiters, linefeed} set s to xs as text set my text item delimiters to dlm s end unlines
http://rosettacode.org/wiki/Hailstone_sequence
Hailstone sequence
The Hailstone sequence of numbers can be generated from a starting positive integer,   n   by:   If   n   is     1     then the sequence ends.   If   n   is   even then the next   n   of the sequence   = n/2   If   n   is   odd   then the next   n   of the sequence   = (3 * n) + 1 The (unproven) Collatz conjecture is that the hailstone sequence for any starting number always terminates. This sequence was named by Lothar Collatz in 1937   (or possibly in 1939),   and is also known as (the):   hailstone sequence,   hailstone numbers   3x + 2 mapping,   3n + 1 problem   Collatz sequence   Hasse's algorithm   Kakutani's problem   Syracuse algorithm,   Syracuse problem   Thwaites conjecture   Ulam's problem The hailstone sequence is also known as   hailstone numbers   (because the values are usually subject to multiple descents and ascents like hailstones in a cloud). Task Create a routine to generate the hailstone sequence for a number. Use the routine to show that the hailstone sequence for the number 27 has 112 elements starting with 27, 82, 41, 124 and ending with 8, 4, 2, 1 Show the number less than 100,000 which has the longest hailstone sequence together with that sequence's length.   (But don't show the actual sequence!) See also   xkcd (humourous).   The Notorious Collatz conjecture Terence Tao, UCLA (Presentation, pdf).   The Simplest Math Problem No One Can Solve Veritasium (video, sponsored).
#Sidef
Sidef
func hailstone (n) { var sequence = [n] while (n > 1) { sequence << ( n.is_even ? n.div!(2)  : n.mul!(3).add!(1) ) } return(sequence) }   # The hailstone sequence for the number 27 var arr = hailstone(var nr = 27) say "#{nr}: #{arr.first(4)} ... #{arr.last(4)} (#{arr.len})"   # The longest hailstone sequence for a number less than 100,000 var h = [0, 0] for i (1 .. 99_999) { (var l = hailstone(i).len) > h[1] && ( h = [i, l] ) }   printf("%d: (%d)\n", h...)
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} 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!
byte X   Proc Main()   For X=97 To 122 Do Put(x) Od   Return
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} 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
type Lower_Case is new Character range 'a' .. 'z';
http://rosettacode.org/wiki/Hello_world/Text
Hello world/Text
Hello world/Text is part of Short Circuit's Console Program Basics selection. Task Display the string Hello world! on a text console. Related tasks   Hello world/Graphical   Hello world/Line Printer   Hello world/Newbie   Hello world/Newline omission   Hello world/Standard error   Hello world/Web server
#Nemerle
Nemerle
  class Hello { static Main () : void { System.Console.WriteLine ("Hello world!"); } }  
http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation. That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange. Generic swap is a task which brings together a few separate issues in programming language semantics. Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places. Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities. Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism). Do your best!
#SenseTalk
SenseTalk
  set [x,y] to [13,"Hello"] -- assign values to two variables put x,y put set [x,y] to [y,x] -- swap the variable values put x,y  
http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation. That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange. Generic swap is a task which brings together a few separate issues in programming language semantics. Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places. Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities. Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism). Do your best!
#Sidef
Sidef
func swap(Ref a, Ref b) { var tmp = *a; *a = *b; *b = tmp; }
http://rosettacode.org/wiki/Greatest_element_of_a_list
Greatest element of a list
Task Create a function that returns the maximum value in a provided set of values, where the number of values may not be known until run-time.
#Yorick
Yorick
> foo = [4, 3, 2, 7, 8, 9] > max(foo) 9
http://rosettacode.org/wiki/Greatest_element_of_a_list
Greatest element of a list
Task Create a function that returns the maximum value in a provided set of values, where the number of values may not be known until run-time.
#zkl
zkl
(1).max(1,2,3) //-->3 (66).max(1,2,3.14) //-->66
http://rosettacode.org/wiki/Generator/Exponential
Generator/Exponential
A generator is an executable entity (like a function or procedure) that contains code that yields a sequence of values, one at a time, so that each time you call the generator, the next value in the sequence is provided. Generators are often built on top of coroutines or objects so that the internal state of the object is handled “naturally”. Generators are often used in situations where a sequence is potentially infinite, and where it is possible to construct the next value of the sequence with only minimal state. Task Create a function that returns a generation of the m'th powers of the positive integers starting from zero, in order, and without obvious or simple upper limit. (Any upper limit to the generator should not be stated in the source but should be down to factors such as the languages natural integer size limit or computational time/size). Use it to create a generator of:   Squares.   Cubes. Create a new generator that filters all cubes from the generator of squares. Drop the first 20 values from this last generator of filtered results, and then show the next 10 values. Note that this task requires the use of generators in the calculation of the result. Also see Generator
#E
E
def genPowers(exponent) { var i := -1 return def powerGenerator() { return (i += 1) ** exponent } }   def filtered(source, filter) { var fval := filter() return def filterGenerator() { while (true) { def sval := source() while (sval > fval) { fval := filter() } if (sval < fval) { return sval } } } }   def drop(n, gen) { for _ in 1..n { gen() } }     def squares := genPowers(2) def cubes := genPowers(3) def squaresNotCubes := filtered(squares, cubes) drop(20, squaresNotCubes) for _ in 1..10 { print(`${squaresNotCubes()} `) } println()
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#Scheme
Scheme
(define (gcd a b) (if (= b 0) a (gcd b (modulo a b))))
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#Sed
Sed
#! /bin/sed -nf   # gcd.sed Copyright (c) 2010 by Paweł Zuzelski <[email protected]> # dc.sed Copyright (c) 1995 - 1997 by Greg Ubben <[email protected]>   # usage: # # echo N M | ./gcd.sed # # Computes the greatest common divisor of N and M integers using euclidean # algorithm.   s/^/|P|K0|I10|O10|?~/   s/$/ [lalb%sclbsalcsblb0<F]sF sasblFxlap/   :next s/|?./|?/ s/|?#[ -}]*/|?/ /|?!*[lLsS;:<>=]\{0,1\}$/N /|?!*[-+*/%^<>=]/b binop /^|.*|?[dpPfQXZvxkiosStT;:]/b binop /|?[_0-9A-F.]/b number /|?\[/b string /|?l/b load /|?L/b Load /|?[sS]/b save /|?c/ s/[^|]*// /|?d/ s/[^~]*~/&&/ /|?f/ s//&[pSbz0<aLb]dSaxsaLa/ /|?x/ s/\([^~]*~\)\(.*|?x\)~*/\2\1/ /|?[KIO]/ s/.*|\([KIO]\)\([^|]*\).*|?\1/\2~&/ /|?T/ s/\.*0*~/~/ # a slow, non-stackable array implementation in dc, just for completeness # A fast, stackable, associative array implementation could be done in sed # (format: {key}value{key}value...), but would be longer, like load & save. /|?;/ s/|?;\([^{}]\)/|?~[s}s{L{s}q]S}[S}l\1L}1-d0>}s\1L\1l{xS\1]dS{xL}/ /|?:/ s/|?:\([^{}]\)/|?~[s}L{s}L{s}L}s\1q]S}S}S{[L}1-d0>}S}l\1s\1L\1l{xS\1]dS{x/ /|?[ ~ cdfxKIOT]/b next /|?\n/b next /|?[pP]/b print /|?k/ s/^\([0-9]\{1,3\}\)\([.~].*|K\)[^|]*/\2\1/ /|?i/ s/^\(-\{0,1\}[0-9]*\.\{0,1\}[0-9]\{1,\}\)\(~.*|I\)[^|]*/\2\1/ /|?o/ s/^\(-\{0,1\}[1-9][0-9]*\.\{0,1\}[0-9]*\)\(~.*|O\)[^|]*/\2\1/ /|?[kio]/b pop /|?t/b trunc /|??/b input /|?Q/b break /|?q/b quit h /|?[XZz]/b count /|?v/b sqrt s/.*|?\([^Y]\).*/\1 is unimplemented/ s/\n/\\n/g l g b next   :print /^-\{0,1\}[0-9]*\.\{0,1\}[0-9]\{1,\}~.*|?p/!b Print /|O10|/b Print   # Print a number in a non-decimal output base. Uses registers a,b,c,d. # Handles fractional output bases (O<-1 or O>=1), unlike other dc's. # Converts the fraction correctly on negative output bases, unlike # UNIX dc. Also scales the fraction more accurately than UNIX dc. # s,|?p,&KSa0kd[[-]Psa0la-]Sad0>a[0P]sad0=a[A*2+]saOtd0>a1-ZSd[[[[ ]P]sclb1\ !=cSbLdlbtZ[[[-]P0lb-sb]sclb0>c1+]sclb0!<c[0P1+dld>c]scdld>cscSdLbP]q]Sb\ [t[1P1-d0<c]scd0<c]ScO_1>bO1!<cO[16]<bOX0<b[[q]sc[dSbdA>c[A]sbdA=c[B]sbd\ B=c[C]sbdC=c[D]sbdD=c[E]sbdE=c[F]sb]xscLbP]~Sd[dtdZOZ+k1O/Tdsb[.5]*[.1]O\ X^*dZkdXK-1+ktsc0kdSb-[Lbdlb*lc+tdSbO*-lb0!=aldx]dsaxLbsb]sad1!>a[[.]POX\ +sb1[SbO*dtdldx-LbO*dZlb!<a]dsax]sadXd0<asbsasaLasbLbscLcsdLdsdLdLak[]pP, b next   :Print /|?p/s/[^~]*/&\ ~&/ s/\(.*|P\)\([^|]*\)/\ \2\1/ s/\([^~]*\)\n\([^~]*\)\(.*|P\)/\1\3\2/ h s/~.*// /./{ s/.//; p; } # Just s/.//p would work if we knew we were running under the -n option. # Using l vs p would kind of do \ continuations, but would break strings. g   :pop s/[^~]*~// b next   :load s/\(.*|?.\)\(.\)/\20~\1/ s/^\(.\)0\(.*|r\1\([^~|]*\)~\)/\1\3\2/ s/.// b next   :Load s/\(.*|?.\)\(.\)/\2\1/ s/^\(.\)\(.*|r\1\)\([^~|]*~\)/|\3\2/ /^|/!i\ register empty s/.// b next   :save s/\(.*|?.\)\(.\)/\2\1/ /^\(.\).*|r\1/ !s/\(.\).*|/&r\1|/ /|?S/ s/\(.\).*|r\1/&~/ s/\(.\)\([^~]*~\)\(.*|r\1\)[^~|]*~\{0,1\}/\3\2/ b next   :quit t quit s/|?[^~]*~[^~]*~/|?q/ t next # Really should be using the -n option to avoid printing a final newline. s/.*|P\([^|]*\).*/\1/ q   :break s/[0-9]*/&;987654321009;/ :break1 s/^\([^;]*\)\([1-9]\)\(0*\)\([^1]*\2\(.\)[^;]*\3\(9*\).*|?.\)[^~]*~/\1\5\6\4/ t break1 b pop   :input N s/|??\(.*\)\(\n.*\)/|?\2~\1/ b next   :count /|?Z/ s/~.*// /^-\{0,1\}[0-9]*\.\{0,1\}[0-9]\{1,\}$/ s/[-.0]*\([^.]*\)\.*/\1/ /|?X/ s/-*[0-9A-F]*\.*\([0-9A-F]*\).*/\1/ s/|.*// /~/ s/[^~]//g   s/./a/g :count1 s/a\{10\}/b/g s/b*a*/&a9876543210;/ s/a.\{9\}\(.\).*;/\1/ y/b/a/ /a/b count1 G /|?z/ s/\n/&~/ s/\n[^~]*// b next   :trunc # for efficiency, doesn't pad with 0s, so 10k 2 5/ returns just .40 # The X* here and in a couple other places works around a SunOS 4.x sed bug. s/\([^.~]*\.*\)\(.*|K\([^|]*\)\)/\3;9876543210009909:\1,\2/ :trunc1 s/^\([^;]*\)\([1-9]\)\(0*\)\([^1]*\2\(.\)[^:]*X*\3\(9*\)[^,]*\),\([0-9]\)/\1\5\6\4\7,/ t trunc1 s/[^:]*:\([^,]*\)[^~]*/\1/ b normal   :number s/\(.*|?\)\(_\{0,1\}[0-9A-F]*\.\{0,1\}[0-9A-F]*\)/\2~\1~/ s/^_/-/ /^[^A-F~]*~.*|I10|/b normal /^[-0.]*~/b normal s:\([^.~]*\)\.*\([^~]*\):[Ilb^lbk/,\1\2~0A1B2C3D4E5F1=11223344556677889900;.\2: :digit s/^\([^,]*\),\(-*\)\([0-F]\)\([^;]*\(.\)\3[^1;]*\(1*\)\)/I*+\1\2\6\5~,\2\4/ t digit s:...\([^/]*.\)\([^,]*\)[^.]*\(.*|?.\):\2\3KSb[99]k\1]SaSaXSbLalb0<aLakLbktLbk: b next   :string /|?[^]]*$/N s/\(|?[^]]*\)\[\([^]]*\)]/\1|{\2|}/ /|?\[/b string s/\(.*|?\)|{\(.*\)|}/\2~\1[/ s/|{/[/g s/|}/]/g b next   :binop /^[^~|]*~[^|]/ !i\ stack empty //!b next /^-\{0,1\}[0-9]*\.\{0,1\}[0-9]\{1,\}~/ !s/[^~]*\(.*|?!*[^!=<>]\)/0\1/ /^[^~]*~-\{0,1\}[0-9]*\.\{0,1\}[0-9]\{1,\}~/ !s/~[^~]*\(.*|?!*[^!=<>]\)/~0\1/ h /|?\*/b mul /|?\//b div /|?%/b rem /|?^/b exp   /|?[+-]/ s/^\(-*\)\([^~]*~\)\(-*\)\([^~]*~\).*|?\(-\{0,1\}\).*/\2\4s\3o\1\3\5/ s/\([^.~]*\)\([^~]*~[^.~]*\)\(.*\)/<\1,\2,\3|=-~.0,123456789<></ /^<\([^,]*,[^~]*\)\.*0*~\1\.*0*~/ s/</=/ :cmp1 s/^\(<[^,]*\)\([0-9]\),\([^,]*\)\([0-9]\),/\1,\2\3,\4/ t cmp1 /^<\([^~]*\)\([^~]\)[^~]*~\1\(.\).*|=.*\3.*\2/ s/</>/ /|?/{ s/^\([<>]\)\(-[^~]*~-.*\1\)\(.\)/\3\2/ s/^\(.\)\(.*|?!*\)\1/\2!\1/ s/|?![^!]\(.\)/&l\1x/ s/[^~]*~[^~]*~\(.*|?\)!*.\(.*\)|=.*/\1\2/ b next } s/\(-*\)\1|=.*/;9876543210;9876543210/ /o-/ s/;9876543210/;0123456789/ s/^>\([^~]*~\)\([^~]*~\)s\(-*\)\(-*o\3\(-*\)\)/>\2\1s\5\4/   s/,\([0-9]*\)\.*\([^,]*\),\([0-9]*\)\.*\([0-9]*\)/\1,\2\3.,\4;0/ :right1 s/,\([0-9]\)\([^,]*\),;*\([0-9]\)\([0-9]*\);*0*/\1,\2\3,\4;0/ t right1 s/.\([^,]*\),~\(.*\);0~s\(-*\)o-*/\1~\30\2~/   :addsub1 s/\(.\{0,1\}\)\(~[^,]*\)\([0-9]\)\(\.*\),\([^;]*\)\(;\([^;]*\(\3[^;]*\)\).*X*\1\(.*\)\)/\2,\4\5\9\8\7\6/ s/,\([^~]*~\).\{10\}\(.\)[^;]\{0,9\}\([^;]\{0,1\}\)[^;]*/,\2\1\3/ # could be done in one s/// if we could have >9 back-refs... /^~.*~;/!b addsub1   :endbin s/.\([^,]*\),\([0-9.]*\).*/\1\2/ G s/\n[^~]*~[^~]*//   :normal s/^\(-*\)0*\([0-9.]*[0-9]\)[^~]*/\1\2/ s/^[^1-9~]*~/0~/ b next   :mul s/\(-*\)\([0-9]*\)\.*\([0-9]*\)~\(-*\)\([0-9]*\)\.*\([0-9]*\).*|K\([^|]*\).*/\1\4\2\5.!\3\6,|\2<\3~\5>\6:\7;9876543210009909/   :mul1 s/![0-9]\([^<]*\)<\([0-9]\{0,1\}\)\([^>]*\)>\([0-9]\{0,1\}\)/0!\1\2<\3\4>/ /![0-9]/ s/\(:[^;]*\)\([1-9]\)\(0*\)\([^0]*\2\(.\).*X*\3\(9*\)\)/\1\5\6\4/ /<~[^>]*>:0*;/!t mul1   s/\(-*\)\1\([^>]*\).*/;\2^>:9876543210aaaaaaaaa/   :mul2 s/\([0-9]~*\)^/^\1/ s/<\([0-9]*\)\(.*[~^]\)\([0-9]*\)>/\1<\2>\3/    :mul3 s/>\([0-9]\)\(.*\1.\{9\}\(a*\)\)/\1>\2;9\38\37\36\35\34\33\32\31\30/ s/\(;[^<]*\)\([0-9]\)<\([^;]*\).*\2[0-9]*\(.*\)/\4\1<\2\3/ s/a[0-9]/a/g s/a\{10\}/b/g s/b\{10\}/c/g /|0*[1-9][^>]*>0*[1-9]/b mul3   s/;/a9876543210;/ s/a.\{9\}\(.\)[^;]*\([^,]*\)[0-9]\([.!]*\),/\2,\1\3/ y/cb/ba/ /|<^/!b mul2 b endbin   :div # CDDET /^[-.0]*[1-9]/ !i\ divide by 0 //!b pop s/\(-*\)\([0-9]*\)\.*\([^~]*~-*\)\([0-9]*\)\.*\([^~]*\)/\2.\3\1;0\4.\5;0/ :div1 s/^\.0\([^.]*\)\.;*\([0-9]\)\([0-9]*\);*0*/.\1\2.\3;0/ s/^\([^.]*\)\([0-9]\)\.\([^;]*;\)0*\([0-9]*\)\([0-9]\)\./\1.\2\30\4.\5/ t div1 s/~\(-*\)\1\(-*\);0*\([^;]*[0-9]\)[^~]*/~123456789743222111~\2\3/ s/\(.\(.\)[^~]*\)[^9]*\2.\{8\}\(.\)[^~]*/\3~\1/ s,|?.,&SaSadSaKdlaZ+LaX-1+[sb1]Sbd1>bkLatsbLa[dSa2lbla*-*dLa!=a]dSaxsakLasbLb*t, b next   :rem s,|?%,&Sadla/LaKSa[999]k*Lak-, b next   :exp # This decimal method is just a little faster than the binary method done # totally in dc: 1LaKLb [kdSb*LbK]Sb [[.5]*d0ktdSa<bkd*KLad1<a]Sa d1<a kk* /^[^~]*\./i\ fraction in exponent ignored s,[^-0-9].*,;9d**dd*8*d*d7dd**d*6d**d5d*d*4*d3d*2lbd**1lb*0, :exp1 s/\([0-9]\);\(.*\1\([d*]*\)[^l]*\([^*]*\)\(\**\)\)/;dd*d**d*\4\3\5\2/ t exp1 G s,-*.\{9\}\([^9]*\)[^0]*0.\(.*|?.\),\2~saSaKdsaLb0kLbkK*+k1\1LaktsbkLax, s,|?.,&SadSbdXSaZla-SbKLaLadSb[0Lb-d1lb-*d+K+0kkSb[1Lb/]q]Sa0>a[dk]sadK<a[Lb], b next   :sqrt # first square root using sed: 8k2v at 1:30am Dec 17, 1996 /^-/i\ square root of negative number /^[-0]/b next s/~.*// /^\./ s/0\([0-9]\)/\1/g /^\./ !s/[0-9][0-9]/7/g G s/\n/~/ s,|?.,&K1+k KSbSb[dk]SadXdK<asadlb/lb+[.5]*[sbdlb/lb+[.5]*dlb>a]dsaxsasaLbsaLatLbk K1-kt, b next   # END OF GSU dc.sed
http://rosettacode.org/wiki/Generate_Chess960_starting_position
Generate Chess960 starting position
Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints: as in the standard chess game, all eight white pawns must be placed on the second rank. White pieces must stand on the first rank as in the standard game, in random column order but with the two following constraints: the bishops must be placed on opposite color squares (i.e. they must be an odd number of spaces apart or there must be an even number of spaces between them) the King must be between two rooks (with any number of other pieces between them all) Black pawns and pieces must be placed respectively on the seventh and eighth ranks, mirroring the white pawns and pieces, just as in the standard game. (That is, their positions are not independently randomized.) With those constraints there are 960 possible starting positions, thus the name of the variant. Task The purpose of this task is to write a program that can randomly generate any one of the 960 Chess960 initial positions. You will show the result as the first rank displayed with Chess symbols in Unicode: ♔♕♖♗♘ or with the letters King Queen Rook Bishop kNight.
#C
C
#include<stdlib.h> #include<locale.h> #include<wchar.h> #include<stdio.h> #include<time.h>   char rank[9];   int pos[8];   void swap(int i,int j){ int temp = pos[i]; pos[i] = pos[j]; pos[j] = temp; }   void generateFirstRank(){ int kPos,qPos,bPos1,bPos2,rPos1,rPos2,nPos1,nPos2,i;   for(i=0;i<8;i++){ rank[i] = 'e'; pos[i] = i; }   do{ kPos = rand()%8; rPos1 = rand()%8; rPos2 = rand()%8; }while((rPos1-kPos<=0 && rPos2-kPos<=0)||(rPos1-kPos>=0 && rPos2-kPos>=0)||(rPos1==rPos2 || kPos==rPos1 || kPos==rPos2));   rank[pos[rPos1]] = 'R'; rank[pos[kPos]] = 'K'; rank[pos[rPos2]] = 'R';   swap(rPos1,7); swap(rPos2,6); swap(kPos,5);   do{ bPos1 = rand()%5; bPos2 = rand()%5; }while(((pos[bPos1]-pos[bPos2])%2==0)||(bPos1==bPos2));   rank[pos[bPos1]] = 'B'; rank[pos[bPos2]] = 'B';   swap(bPos1,4); swap(bPos2,3);   do{ qPos = rand()%3; nPos1 = rand()%3; }while(qPos==nPos1);   rank[pos[qPos]] = 'Q'; rank[pos[nPos1]] = 'N';   for(i=0;i<8;i++) if(rank[i]=='e'){ rank[i] = 'N'; break; } }   void printRank(){ int i;   #ifdef _WIN32 printf("%s\n",rank); #else { setlocale(LC_ALL,""); printf("\n"); for(i=0;i<8;i++){ if(rank[i]=='K') printf("%lc",(wint_t)9812); else if(rank[i]=='Q') printf("%lc",(wint_t)9813); else if(rank[i]=='R') printf("%lc",(wint_t)9814); else if(rank[i]=='B') printf("%lc",(wint_t)9815); if(rank[i]=='N') printf("%lc",(wint_t)9816); } } #endif }   int main() { int i;   srand((unsigned)time(NULL));   for(i=0;i<9;i++){ generateFirstRank(); printRank(); }   return 0; }  
http://rosettacode.org/wiki/Gapful_numbers
Gapful numbers
Numbers   (positive integers expressed in base ten)   that are (evenly) divisible by the number formed by the first and last digit are known as   gapful numbers. Evenly divisible   means divisible with   no   remainder. All   one─   and two─digit   numbers have this property and are trivially excluded.   Only numbers   ≥ 100   will be considered for this Rosetta Code task. Example 187   is a   gapful   number because it is evenly divisible by the number   17   which is formed by the first and last decimal digits of   187. About   7.46%   of positive integers are   gapful. Task   Generate and show all sets of numbers (below) on one line (horizontally) with a title,   here on this page   Show the first   30   gapful numbers   Show the first   15   gapful numbers   ≥          1,000,000   Show the first   10   gapful numbers   ≥   1,000,000,000 Related tasks   Harshad or Niven series.   palindromic gapful numbers.   largest number divisible by its digits. Also see   The OEIS entry:   A108343 gapful numbers.   numbersaplenty gapful numbers
#11l
11l
L(start, n) [(100, 30), (1'000'000, 15), (1'000'000'000, 10)] print("\nFirst "n‘ gapful numbers from ’start) [Int] l L(x) start.. I x % (Int(String(x)[0]) * 10 + (x % 10)) == 0 l.append(x) I l.len == n L.break print(l)
http://rosettacode.org/wiki/Generate_random_chess_position
Generate random chess position
Task Generate a random chess position in FEN format. The position does not have to be realistic or even balanced,  but it must comply to the following rules: there is one and only one king of each color  (one black king and one white king); the kings must not be placed on adjacent squares; there can not be any pawn in the promotion square  (no white pawn in the eighth rank, and no black pawn in the first rank); including the kings, up to 32 pieces of either color can be placed. There is no requirement for material balance between sides. The picking of pieces does not have to comply to a regular chess set --- there can be five knights, twenty rooks, whatever ... as long as the total number of pieces do not exceed thirty-two. it is white's turn. It's assumed that both sides have lost castling rights and that there is no possibility for   en passant   (the FEN should thus end in w - - 0 1). No requirement is made regarding the probability distribution of your method, but your program should be able to span a reasonably representative sample of all possible positions. For instance, programs that would always generate positions with say five pieces on the board, or with kings on a corner, would not be considered truly random.
#Go
Go
package main   import ( "fmt" "math/rand" "strconv" "strings" "time" )   var grid [8][8]byte   func abs(i int) int { if i >= 0 { return i } else { return -i } }   func createFen() string { placeKings() placePieces("PPPPPPPP", true) placePieces("pppppppp", true) placePieces("RNBQBNR", false) placePieces("rnbqbnr", false) return toFen() }   func placeKings() { for { r1 := rand.Intn(8) c1 := rand.Intn(8) r2 := rand.Intn(8) c2 := rand.Intn(8) if r1 != r2 && abs(r1-r2) > 1 && abs(c1-c2) > 1 { grid[r1][c1] = 'K' grid[r2][c2] = 'k' return } } }   func placePieces(pieces string, isPawn bool) { numToPlace := rand.Intn(len(pieces)) for n := 0; n < numToPlace; n++ { var r, c int for { r = rand.Intn(8) c = rand.Intn(8) if grid[r][c] == '\000' && !(isPawn && (r == 7 || r == 0)) { break } } grid[r][c] = pieces[n] } }   func toFen() string { var fen strings.Builder countEmpty := 0 for r := 0; r < 8; r++ { for c := 0; c < 8; c++ { ch := grid[r][c] if ch == '\000' { ch = '.' } fmt.Printf("%2c ", ch) if ch == '.' { countEmpty++ } else { if countEmpty > 0 { fen.WriteString(strconv.Itoa(countEmpty)) countEmpty = 0 } fen.WriteByte(ch) } } if countEmpty > 0 { fen.WriteString(strconv.Itoa(countEmpty)) countEmpty = 0 } fen.WriteString("/") fmt.Println() } fen.WriteString(" w - - 0 1") return fen.String() }   func main() { rand.Seed(time.Now().UnixNano()) fmt.Println(createFen()) }
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#Arturo
Arturo
maxNum: to :integer strip input "Set maximum number: " facts: map 1..3 'x -> split.words strip input ~"Enter factor |x|: " loop 1..maxNum 'i [ printNum: true loop facts 'fact -> if zero? i % to :integer fact\0 [ prints fact\1 printNum: false ] print (printNum)? -> i -> "" ]
http://rosettacode.org/wiki/Hailstone_sequence
Hailstone sequence
The Hailstone sequence of numbers can be generated from a starting positive integer,   n   by:   If   n   is     1     then the sequence ends.   If   n   is   even then the next   n   of the sequence   = n/2   If   n   is   odd   then the next   n   of the sequence   = (3 * n) + 1 The (unproven) Collatz conjecture is that the hailstone sequence for any starting number always terminates. This sequence was named by Lothar Collatz in 1937   (or possibly in 1939),   and is also known as (the):   hailstone sequence,   hailstone numbers   3x + 2 mapping,   3n + 1 problem   Collatz sequence   Hasse's algorithm   Kakutani's problem   Syracuse algorithm,   Syracuse problem   Thwaites conjecture   Ulam's problem The hailstone sequence is also known as   hailstone numbers   (because the values are usually subject to multiple descents and ascents like hailstones in a cloud). Task Create a routine to generate the hailstone sequence for a number. Use the routine to show that the hailstone sequence for the number 27 has 112 elements starting with 27, 82, 41, 124 and ending with 8, 4, 2, 1 Show the number less than 100,000 which has the longest hailstone sequence together with that sequence's length.   (But don't show the actual sequence!) See also   xkcd (humourous).   The Notorious Collatz conjecture Terence Tao, UCLA (Presentation, pdf).   The Simplest Math Problem No One Can Solve Veritasium (video, sponsored).
#Smalltalk
Smalltalk
Object subclass: Sequences [ Sequences class >> hailstone: n [ |seq| seq := OrderedCollection new. seq add: n. (n = 1) ifTrue: [ ^seq ]. (n even) ifTrue: [ seq addAll: (Sequences hailstone: (n / 2)) ] ifFalse: [ seq addAll: (Sequences hailstone: ( (3*n) + 1 ) ) ]. ^seq. ]   Sequences class >> hailstoneCount: n [ ^ (Sequences hailstoneCount: n num: 1) ]   "this 'version' avoids storing the sequence, it just counts its length - no memoization anyway" Sequences class >> hailstoneCount: n num: m [ (n = 1) ifTrue: [ ^m ]. (n even) ifTrue: [ ^ Sequences hailstoneCount: (n / 2) num: (m + 1) ] ifFalse: [ ^ Sequences hailstoneCount: ( (3*n) + 1) num: (m + 1) ]. ] ].
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} 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
# in ALGOL 68, a STRING is an array of characters with flexible bounds # # so we can declare an array of 26 characters and assign a string # # containing the lower-case letters to it #   [ 26 ]CHAR lc := "abcdefghijklmnopqrstuvwxyz"  
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} 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_W
ALGOL W
 % set lc to the lower case alphabet  % string(26) lc; for c := 0 until 25 do lc( c // 1 ) := code( decode( "a" ) + c );
http://rosettacode.org/wiki/Hello_world/Text
Hello world/Text
Hello world/Text is part of Short Circuit's Console Program Basics selection. Task Display the string Hello world! on a text console. Related tasks   Hello world/Graphical   Hello world/Line Printer   Hello world/Newbie   Hello world/Newline omission   Hello world/Standard error   Hello world/Web server
#NetRexx
NetRexx
say 'Hello world!'
http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation. That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange. Generic swap is a task which brings together a few separate issues in programming language semantics. Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places. Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities. Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism). Do your best!
#Slate
Slate
x@(Syntax LoadVariable traits) swapWith: y@(Syntax LoadVariable traits) &environment: env "A macro that expands into simple code swapping the values of two variables in the current scope." [ env ifNil: [error: 'Cannot swap variables outside of a method']. tmpVar ::= env addVariable. {tmpVar store: x variable load. x variable store: y variable load. y variable store: tmpVar load} parenthesize ].
http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation. That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange. Generic swap is a task which brings together a few separate issues in programming language semantics. Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places. Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities. Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism). Do your best!
#Smalltalk
Smalltalk
OrderedCollection extend [ swap: a and: b [ |t| t := self at: a. self at: a put: (self at: b). self at: b put: t ] ]
http://rosettacode.org/wiki/Greatest_element_of_a_list
Greatest element of a list
Task Create a function that returns the maximum value in a provided set of values, where the number of values may not be known until run-time.
#Zoea
Zoea
  program: max case: 1 input: [7,3,5,9,2,6] output: 9 case: 2 input: [1,5,3,2,7] output: 7  
http://rosettacode.org/wiki/Greatest_element_of_a_list
Greatest element of a list
Task Create a function that returns the maximum value in a provided set of values, where the number of values may not be known until run-time.
#ZX_Spectrum_Basic
ZX Spectrum Basic
10 PRINT "Values"'' 20 LET z=0 30 FOR x=1 TO INT (RND*10)+1 40 LET y=RND*10-5 50 PRINT y 60 LET z=(y AND y>z)+(z AND y<z) 70 NEXT x 80 PRINT '"Max. value = ";z
http://rosettacode.org/wiki/Generator/Exponential
Generator/Exponential
A generator is an executable entity (like a function or procedure) that contains code that yields a sequence of values, one at a time, so that each time you call the generator, the next value in the sequence is provided. Generators are often built on top of coroutines or objects so that the internal state of the object is handled “naturally”. Generators are often used in situations where a sequence is potentially infinite, and where it is possible to construct the next value of the sequence with only minimal state. Task Create a function that returns a generation of the m'th powers of the positive integers starting from zero, in order, and without obvious or simple upper limit. (Any upper limit to the generator should not be stated in the source but should be down to factors such as the languages natural integer size limit or computational time/size). Use it to create a generator of:   Squares.   Cubes. Create a new generator that filters all cubes from the generator of squares. Drop the first 20 values from this last generator of filtered results, and then show the next 10 values. Note that this task requires the use of generators in the calculation of the result. Also see Generator
#EchoLisp
EchoLisp
  (lib 'tasks) ;; for make-generator   ;; generator of generators (define (gen-power power) (make-generator (lambda(n) (yield (expt n power)) (1+ n)) 1))   (define powers-2 (gen-power 2)) (define powers-3 (gen-power 3))   (take powers-3 10) → (1 8 27 64 125 216 343 512 729 1000)   ;; generators substraction ;; input : two generators ga, gb - Sequences must be increasing ;; output : new generator = ga sequence minus gb sequence   (define (gen-substract ga gb) (define (substract b (a)) (set! a (next ga)) (while (>= a b) ; avance b until > a (when (= a b) (set! a (next ga))) (set! b (next gb))) (yield a) b ) ;; b := next state (make-generator substract (next gb)))   ;; application (define task (gen-substract (gen-power 2) (gen-power 3)))   (drop task 20) (take task 10) → (529 576 625 676 784 841 900 961 1024 1089)   ; inspect task → #generator:state: 1331  
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#Seed7
Seed7
const func integer: gcd (in var integer: a, in var integer: b) is func result var integer: gcd is 0; local var integer: help is 0; begin while a <> 0 do help := b rem a; b := a; a := help; end while; gcd := b; end func;
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#SequenceL
SequenceL
gcd(a, b) := a when b = 0 else gcd(b, a mod b);
http://rosettacode.org/wiki/Generate_Chess960_starting_position
Generate Chess960 starting position
Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints: as in the standard chess game, all eight white pawns must be placed on the second rank. White pieces must stand on the first rank as in the standard game, in random column order but with the two following constraints: the bishops must be placed on opposite color squares (i.e. they must be an odd number of spaces apart or there must be an even number of spaces between them) the King must be between two rooks (with any number of other pieces between them all) Black pawns and pieces must be placed respectively on the seventh and eighth ranks, mirroring the white pawns and pieces, just as in the standard game. (That is, their positions are not independently randomized.) With those constraints there are 960 possible starting positions, thus the name of the variant. Task The purpose of this task is to write a program that can randomly generate any one of the 960 Chess960 initial positions. You will show the result as the first rank displayed with Chess symbols in Unicode: ♔♕♖♗♘ or with the letters King Queen Rook Bishop kNight.
#C.2B.2B
C++
#include <iostream> #include <string> #include <time.h> using namespace std;   namespace { void placeRandomly(char* p, char c) { int loc = rand() % 8; if (!p[loc]) p[loc] = c; else placeRandomly(p, c); // try again } int placeFirst(char* p, char c, int loc = 0) { while (p[loc]) ++loc; p[loc] = c; return loc; }   string startPos() { char p[8]; memset( p, 0, 8 );   // bishops on opposite color p[2 * (rand() % 4)] = 'B'; p[2 * (rand() % 4) + 1] = 'B';   // queen knight knight, anywhere for (char c : "QNN") placeRandomly(p, c);   // rook king rook, in that order placeFirst(p, 'R', placeFirst(p, 'K', placeFirst(p, 'R')));   return string(p, 8); } } // leave local   namespace chess960 { void generate( int c ) { for( int x = 0; x < c; x++ ) cout << startPos() << "\n"; } }   int main( int argc, char* argv[] ) { srand( time( NULL ) ); chess960::generate( 10 ); cout << "\n\n"; return system( "pause" ); }  
http://rosettacode.org/wiki/Gapful_numbers
Gapful numbers
Numbers   (positive integers expressed in base ten)   that are (evenly) divisible by the number formed by the first and last digit are known as   gapful numbers. Evenly divisible   means divisible with   no   remainder. All   one─   and two─digit   numbers have this property and are trivially excluded.   Only numbers   ≥ 100   will be considered for this Rosetta Code task. Example 187   is a   gapful   number because it is evenly divisible by the number   17   which is formed by the first and last decimal digits of   187. About   7.46%   of positive integers are   gapful. Task   Generate and show all sets of numbers (below) on one line (horizontally) with a title,   here on this page   Show the first   30   gapful numbers   Show the first   15   gapful numbers   ≥          1,000,000   Show the first   10   gapful numbers   ≥   1,000,000,000 Related tasks   Harshad or Niven series.   palindromic gapful numbers.   largest number divisible by its digits. Also see   The OEIS entry:   A108343 gapful numbers.   numbersaplenty gapful numbers
#Ada
Ada
with Ada.Text_IO; use Ada.Text_IO;   procedure Gapful_Numbers is   function Divisor (N : in Positive) return Positive is NN : Positive := N; begin while NN >= 10 loop NN := NN / 10; end loop; return 10 * NN + (N mod 10); end Divisor;   function Is_Gapful (N : in Positive) return Boolean is begin return N mod Divisor (N) = 0; end Is_Gapful;   procedure Find_Gapful (Count : in Positive; From : in Positive) is Found : Natural := 0; begin for Candidate in From .. Positive'Last loop if Is_Gapful (Candidate) then Put (Candidate'Image); Found := Found + 1; exit when Found = Count; end if; end loop; New_Line; end Find_Gapful;   begin Put_Line ("First 30 gapful numbers over 100:"); Find_Gapful (From => 100, Count => 30); New_Line;   Put_Line ("First 15 gapful numbers over 1_000_000:"); Find_Gapful (From => 1_000_000, Count => 15); New_Line;   Put_Line ("First 10 gapful numbers over 1_000_000_000:"); Find_Gapful (From => 1_000_000_000, Count => 10); New_Line; end Gapful_Numbers;
http://rosettacode.org/wiki/Generate_random_chess_position
Generate random chess position
Task Generate a random chess position in FEN format. The position does not have to be realistic or even balanced,  but it must comply to the following rules: there is one and only one king of each color  (one black king and one white king); the kings must not be placed on adjacent squares; there can not be any pawn in the promotion square  (no white pawn in the eighth rank, and no black pawn in the first rank); including the kings, up to 32 pieces of either color can be placed. There is no requirement for material balance between sides. The picking of pieces does not have to comply to a regular chess set --- there can be five knights, twenty rooks, whatever ... as long as the total number of pieces do not exceed thirty-two. it is white's turn. It's assumed that both sides have lost castling rights and that there is no possibility for   en passant   (the FEN should thus end in w - - 0 1). No requirement is made regarding the probability distribution of your method, but your program should be able to span a reasonably representative sample of all possible positions. For instance, programs that would always generate positions with say five pieces on the board, or with kings on a corner, would not be considered truly random.
#Haskell
Haskell
{-# LANGUAGE LambdaCase, TupleSections #-}   module RandomChess ( placeKings , placePawns , placeRemaining , emptyBoard , toFen , ChessBoard , Square (..) , BoardState (..) , getBoard ) where   import Control.Monad.State (State, get, gets, put) import Data.List (find, sortBy) import System.Random (Random, RandomGen, StdGen, random, randomR)   type Pos = (Char, Int)   type ChessBoard = [(Square, Pos)]   data PieceRank = King | Queen | Rook | Bishop | Knight | Pawn deriving (Enum, Bounded, Show, Eq, Ord) data PieceColor = Black | White deriving (Enum, Bounded, Show, Eq, Ord)   data Square = ChessPiece PieceRank PieceColor | EmptySquare deriving (Eq, Ord)   type PieceCount = [(Square, Int)]   data BoardState = BoardState { board :: ChessBoard , generator :: StdGen }   instance Show Square where show (ChessPiece King Black) = "♚" show (ChessPiece Queen Black) = "♛" show (ChessPiece Rook Black) = "♜" show (ChessPiece Bishop Black) = "♝" show (ChessPiece Knight Black) = "♞" show (ChessPiece Pawn Black) = "♟" show (ChessPiece King White) = "♔" show (ChessPiece Queen White) = "♕" show (ChessPiece Rook White) = "♖" show (ChessPiece Bishop White) = "♗" show (ChessPiece Knight White) = "♘" show (ChessPiece Pawn White) = "♙" show EmptySquare = " "   instance Random PieceRank where randomR (a, b) g = case randomR (fromEnum a, fromEnum b) g of (x, g'') -> (toEnum x, g'') random = randomR (minBound, maxBound)   instance Random PieceColor where randomR (a, b) g = case randomR (fromEnum a, fromEnum b) g of (x, g'') -> (toEnum x, g'') random = randomR (minBound, maxBound)   fullBoard :: PieceCount fullBoard = [ (ChessPiece King Black , 1) , (ChessPiece Queen Black , 1) , (ChessPiece Rook Black , 2) , (ChessPiece Bishop Black, 2) , (ChessPiece Knight Black, 2) , (ChessPiece Pawn Black , 8) , (ChessPiece King White , 1) , (ChessPiece Queen White , 1) , (ChessPiece Rook White , 2) , (ChessPiece Bishop White, 2) , (ChessPiece Knight White, 2) , (ChessPiece Pawn White , 8) , (EmptySquare , 32) ]   emptyBoard :: ChessBoard emptyBoard = fmap (EmptySquare,) . (,) <$> ['a'..'h'] <*> [1..8]   replaceSquareByPos :: (Square, Pos) -> ChessBoard -> ChessBoard replaceSquareByPos e@(_, p) = fmap (\x -> if p == snd x then e else x)   isPosOccupied :: Pos -> ChessBoard -> Bool isPosOccupied p = occupied . find (\x -> p == snd x) where occupied (Just (EmptySquare, _)) = False occupied _ = True   isAdjacent :: Pos -> Pos -> Bool isAdjacent (x1, y1) (x2, y2) = let upOrDown = (pred y1 == y2 || succ y1 == y2) leftOrRight = (pred x1 == x2 || succ x1 == x2) in (x2 == x1 && upOrDown) || (pred x1 == x2 && upOrDown) || (succ x1 == x2 && upOrDown) || (leftOrRight && y1 == y2)   fen :: Square -> String fen (ChessPiece King Black) = "k" fen (ChessPiece Queen Black) = "q" fen (ChessPiece Rook Black) = "r" fen (ChessPiece Bishop Black) = "b" fen (ChessPiece Knight Black) = "n" fen (ChessPiece Pawn Black) = "p" fen (ChessPiece King White) = "K" fen (ChessPiece Queen White) = "Q" fen (ChessPiece Rook White) = "R" fen (ChessPiece Bishop White) = "B" fen (ChessPiece Knight White) = "N" fen (ChessPiece Pawn White) = "P"   boardSort :: (Square, Pos) -> (Square, Pos) -> Ordering boardSort (_, (x1, y1)) (_, (x2, y2)) | y1 < y2 = GT | y1 > y2 = LT | y1 == y2 = compare x1 x2   toFen :: ChessBoard -> String toFen [] = " w - - 0 1" <> [] toFen b = scanRow (fst <$> take 8 b) 0 where scanRow [] 0 = nextRow scanRow [] n = show n <> nextRow scanRow (EmptySquare:xs) n = scanRow xs (succ n) scanRow (x:xs) 0 = nextPiece x xs scanRow (x:xs) n = show n <> nextPiece x xs nextRow = "/" <> toFen (drop 8 b) nextPiece x xs = fen x <> scanRow xs 0   -- State functions withStateGen :: (StdGen -> (a, StdGen)) -> State BoardState a withStateGen f = do currentState <- get let gen1 = generator currentState let (x, gen2) = f gen1 put (currentState {generator = gen2}) pure x   randomPos :: State BoardState Pos randomPos = do boardState <- gets board chr <- withStateGen (randomR ('a', 'h')) num <- withStateGen (randomR (1, 8)) let pos = (chr, num) if isPosOccupied pos boardState then randomPos else pure pos   randomPiece :: State BoardState Square randomPiece = ChessPiece <$> withStateGen random <*> withStateGen random   placeKings :: State BoardState () placeKings = do currentState <- get p1 <- randomPos p2 <- randomPos if p1 `isAdjacent` p2 || p1 == p2 then placeKings else do let updatedBoard = replaceSquareByPos (ChessPiece King White, p1) $ replaceSquareByPos (ChessPiece King Black, p2) (board currentState) put currentState { board = updatedBoard }   placePawns :: State BoardState () placePawns = withStateGen (randomR (1, 16)) >>= go where go :: Int -> State BoardState () go 0 = pure () go n = do currentState <- get pos <- randomPos color <- withStateGen random let pawn = ChessPiece Pawn color let currentBoard = board currentState if promoted color == snd pos || isPosOccupied pos currentBoard || enpassant color == snd pos || firstPos color == snd pos then go n else do put currentState { board = replaceSquareByPos (pawn, pos) currentBoard } go $ pred n promoted White = 8 promoted Black = 1 enpassant White = 5 enpassant Black = 4 firstPos White = 1 firstPos Black = 8   placeRemaining :: State BoardState () placeRemaining = withStateGen (randomR (5, sum $ fmap snd remaining)) >>= go remaining where remaining = filter (\case (ChessPiece King _, _) -> False (ChessPiece Pawn _, _) -> False (EmptySquare, _) -> False _ -> True) fullBoard   go :: PieceCount -> Int -> State BoardState () go _ 0 = pure () go remaining n = do currentState <- get let currentBoard = board currentState position <- randomPos piece <- randomPiece if not (isPermitted piece) || isPosOccupied position currentBoard then go remaining n else do let updatedBoard = replaceSquareByPos (piece, position) currentBoard put currentState { board = updatedBoard } go (consume piece remaining) (pred n) where isPermitted p = case find ((==p) . fst) remaining of Just (_, count) -> count > 0 Nothing -> False consume p'' = fmap (\(p, c) -> if p == p'' then (p, pred c) else (p, c))   getBoard :: State BoardState ChessBoard getBoard = gets (sortBy boardSort . board)
http://rosettacode.org/wiki/Gauss-Jordan_matrix_inversion
Gauss-Jordan matrix inversion
Task Invert matrix   A   using Gauss-Jordan method. A   being an   n × n   matrix.
#11l
11l
V Eps = 1e-10   F transformToRref(&mat) V lead = 0   L(r) 0 .< mat.len I lead >= mat[0].len R   V i = r L mat[i][lead] == 0 i++ I i == mat.len i = r lead++ I lead == mat[0].len R swap(&mat[i], &mat[r])   V d = mat[r][lead] I abs(d) > Eps L(&item) mat[r] item /= d   L(i) 0 .< mat.len I i != r V m = mat[i][lead] L(c) 0 .< mat[0].len mat[i][c] -= mat[r][c] * m   lead++   F inverse(mat) V augmat = [[0.0] * (2 * mat.len)] * mat.len L(i) 0 .< mat.len L(j) 0 .< mat.len augmat[i][j] = mat[i][j] augmat[i][mat.len + i] = 1   transformToRref(&augmat)   V result = [[0.0] * mat.len] * mat.len L(i) 0 .< mat.len L(j) 0 .< mat.len I augmat[i][j] != Float(i == j) X ValueError(‘matrix is singular’) result[i][j] = augmat[i][mat.len + j] R result   F print_mat(mat) L(row) mat V line = ‘’ L(val) row I !line.empty line ‘’= ‘ ’ line ‘’= ‘#3.5’.format(val) print(line)   F runTest(mat) print(‘Matrix:’) print_mat(mat) print() print(‘Inverse:’) print_mat(inverse(mat)) print() print()   V m1 = [[Float(1), 2, 3], [Float(4), 1, 6], [Float(7), 8, 9]]   V m2 = [[Float( 2), -1, 0], [Float(-1), 2, -1], [Float( 0), -1, 2]]   V m3 = [[Float(-1), -2, 3, 2], [Float(-4), -1, 6, 2], [Float( 7), -8, 9, 1], [Float( 1), -2, 1, 3]]   runTest(m1) runTest(m2) runTest(m3)
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#AutoHotkey
AutoHotkey
; Test parameters max := 20, fizz := 3, buzz := 5, baxx := 7   Loop % max { output := "" if (Mod(A_Index, fizz) = 0) output .= "Fizz" if (Mod(A_Index, buzz) = 0) output .= "Buzz" if (Mod(A_Index, baxx) = 0) output .= "Baxx" if (output = "") FileAppend %A_Index%`n, * else FileAppend %output%`n, * }  
http://rosettacode.org/wiki/Hailstone_sequence
Hailstone sequence
The Hailstone sequence of numbers can be generated from a starting positive integer,   n   by:   If   n   is     1     then the sequence ends.   If   n   is   even then the next   n   of the sequence   = n/2   If   n   is   odd   then the next   n   of the sequence   = (3 * n) + 1 The (unproven) Collatz conjecture is that the hailstone sequence for any starting number always terminates. This sequence was named by Lothar Collatz in 1937   (or possibly in 1939),   and is also known as (the):   hailstone sequence,   hailstone numbers   3x + 2 mapping,   3n + 1 problem   Collatz sequence   Hasse's algorithm   Kakutani's problem   Syracuse algorithm,   Syracuse problem   Thwaites conjecture   Ulam's problem The hailstone sequence is also known as   hailstone numbers   (because the values are usually subject to multiple descents and ascents like hailstones in a cloud). Task Create a routine to generate the hailstone sequence for a number. Use the routine to show that the hailstone sequence for the number 27 has 112 elements starting with 27, 82, 41, 124 and ending with 8, 4, 2, 1 Show the number less than 100,000 which has the longest hailstone sequence together with that sequence's length.   (But don't show the actual sequence!) See also   xkcd (humourous).   The Notorious Collatz conjecture Terence Tao, UCLA (Presentation, pdf).   The Simplest Math Problem No One Can Solve Veritasium (video, sponsored).
#SNUSP
SNUSP
/@+@@@+++# 27 | halve odd /===count<<\ /recurse\ #/?\ zero $>@/===!/===-?\==>?!/-<+++\ \!/=!\@\>?!\@/<@\.!\-/ /+<-\!>\?-<+>/++++<\?>+++/*6+4 | | \=/ \=itoa=@@@+@+++++# \=>?/<=!=\ | |  ! /+ !/+ !/+ !/+ \ mod10 |//!==/========\ | /<+> -\!?-\!?-\!?-\!?-\! /=>?\<=/\<+>!\->+>+<<?/>>=print@/\ln \?!\-?!\-?!\-?!\-?!\-?/\ div10 \+<-/!< ----------.++++++++++/ # +/! +/! +/! +/! +/
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} 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
⎕UCS 96+⍳26
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} 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
-------------------- ALPHABETIC SERIES ------------------- on run unlines(map(concat, ¬ ({enumFromTo("a", "z"), ¬ enumFromTo("🐟", "🐐"), ¬ enumFromTo("z", "a"), ¬ enumFromTo("α", "ω")}))) end run   -------------------- GENERIC FUNCTIONS -------------------   -- concat :: [[a]] -> [a] -- concat :: [String] -> String on concat(xs) set lng to length of xs if 0 < lng and string is class of (item 1 of xs) then set acc to "" else set acc to {} end if repeat with i from 1 to lng set acc to acc & item i of xs end repeat acc end concat   -- enumFromTo :: Enum a => a -> a -> [a] on enumFromTo(m, n) if class of m is integer then enumFromToInt(m, n) else enumFromToChar(m, n) end if end enumFromTo   -- enumFromToChar :: Char -> Char -> [Char] on enumFromToChar(m, n) set {intM, intN} to {id of m, id of n} set xs to {} repeat with i from intM to intN by signum(intN - intM) set end of xs to character id i end repeat return xs end enumFromToChar   -- mReturn :: First-class m => (a -> b) -> m (a -> b) on mReturn(f) -- 2nd class handler function lifted into 1st class script wrapper. if script is class of f then f else script property |λ| : f end script end if end mReturn   -- map :: (a -> b) -> [a] -> [b] on map(f, xs) -- The list obtained by applying f -- to each element of 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   -- signum :: Num -> Num on signum(x) if x < 0 then -1 else if x = 0 then 0 else 1 end if end signum   -- unlines :: [String] -> String on unlines(xs) -- A single string formed by the intercalation -- of a list of strings with the newline character. set {dlm, my text item delimiters} to ¬ {my text item delimiters, linefeed} set s to xs as text set my text item delimiters to dlm s end unlines
http://rosettacode.org/wiki/Hello_world/Text
Hello world/Text
Hello world/Text is part of Short Circuit's Console Program Basics selection. Task Display the string Hello world! on a text console. Related tasks   Hello world/Graphical   Hello world/Line Printer   Hello world/Newbie   Hello world/Newline omission   Hello world/Standard error   Hello world/Web server
#Never
Never
func main() -> int { prints("Hello world!\n"); 0 }
http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation. That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange. Generic swap is a task which brings together a few separate issues in programming language semantics. Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places. Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities. Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism). Do your best!
#SNOBOL4
SNOBOL4
* SWAP(.V1, .V2) - Exchange the contents of two variables. * The variables must be prefixed with the name operator * when the function is called.   DEFINE('SWAP(X,Y)TEMP')  :(SWAP_END) SWAP TEMP = $X $X = $Y $Y = TEMP  :(RETURN) SWAP_END
http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation. That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange. Generic swap is a task which brings together a few separate issues in programming language semantics. Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places. Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities. Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism). Do your best!
#Standard_ML
Standard ML
fun swap (x, y) = (y, x)
http://rosettacode.org/wiki/Generator/Exponential
Generator/Exponential
A generator is an executable entity (like a function or procedure) that contains code that yields a sequence of values, one at a time, so that each time you call the generator, the next value in the sequence is provided. Generators are often built on top of coroutines or objects so that the internal state of the object is handled “naturally”. Generators are often used in situations where a sequence is potentially infinite, and where it is possible to construct the next value of the sequence with only minimal state. Task Create a function that returns a generation of the m'th powers of the positive integers starting from zero, in order, and without obvious or simple upper limit. (Any upper limit to the generator should not be stated in the source but should be down to factors such as the languages natural integer size limit or computational time/size). Use it to create a generator of:   Squares.   Cubes. Create a new generator that filters all cubes from the generator of squares. Drop the first 20 values from this last generator of filtered results, and then show the next 10 values. Note that this task requires the use of generators in the calculation of the result. Also see Generator
#Elixir
Elixir
defmodule Generator do def filter( source_pid, remove_pid ) do first_remove = next( remove_pid ) spawn( fn -> filter_loop(source_pid, remove_pid, first_remove) end ) end   def next( pid ) do send(pid, {:next, self}) receive do x -> x end end   def power( m ), do: spawn( fn -> power_loop(m, 0) end )   def task do squares_pid = power( 2 ) cubes_pid = power( 3 ) filter_pid = filter( squares_pid, cubes_pid ) for _x <- 1..20, do: next(filter_pid) for _x <- 1..10, do: next(filter_pid) end   defp filter_loop( pid1, pid2, n2 ) do receive do {:next, pid} -> {n, new_n2} = filter_loop_next( next(pid1), n2, pid1, pid2 ) send( pid, n ) filter_loop( pid1, pid2, new_n2 ) end end   defp filter_loop_next( n1, n2, pid1, pid2 ) when n1 > n2, do: filter_loop_next( n1, next(pid2), pid1, pid2 ) defp filter_loop_next( n, n, pid1, pid2 ), do: filter_loop_next( next(pid1), next(pid2), pid1, pid2 ) defp filter_loop_next( n1, n2, _pid1, _pid2 ), do: {n1, n2}   defp power_loop( m, n ) do receive do {:next, pid} -> send( pid, round(:math.pow(n, m) ) ) end power_loop( m, n + 1 ) end end   IO.inspect Generator.task
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#SETL
SETL
a := 33; b := 77; print(" the gcd of",a," and ",b," is ",gcd(a,b));   c := 49865; d := 69811; print(" the gcd of",c," and ",d," is ",gcd(c,d));   proc gcd (u, v); return if v = 0 then abs u else gcd (v, u mod v) end; end;
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related task   least common multiple. See also   MathWorld entry:   greatest common divisor.   Wikipedia entry:     greatest common divisor.
#Sidef
Sidef
var arr = [100, 1_000, 10_000, 20]; say Math.gcd(arr...);
http://rosettacode.org/wiki/Generate_Chess960_starting_position
Generate Chess960 starting position
Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints: as in the standard chess game, all eight white pawns must be placed on the second rank. White pieces must stand on the first rank as in the standard game, in random column order but with the two following constraints: the bishops must be placed on opposite color squares (i.e. they must be an odd number of spaces apart or there must be an even number of spaces between them) the King must be between two rooks (with any number of other pieces between them all) Black pawns and pieces must be placed respectively on the seventh and eighth ranks, mirroring the white pawns and pieces, just as in the standard game. (That is, their positions are not independently randomized.) With those constraints there are 960 possible starting positions, thus the name of the variant. Task The purpose of this task is to write a program that can randomly generate any one of the 960 Chess960 initial positions. You will show the result as the first rank displayed with Chess symbols in Unicode: ♔♕♖♗♘ or with the letters King Queen Rook Bishop kNight.
#Clojure
Clojure
(ns c960.core (:gen-class) (:require [clojure.string :as s]))   ;; legal starting rank - unicode chars for rook, knight, bishop, queen, king, bishop, knight, rook (def starting-rank [\♖ \♘ \♗ \♕ \♔ \♗ \♘ \♖])   (defn bishops-legal? "True if Bishops are odd number of indicies apart" [rank] (odd? (apply - (cons 0 (sort > (keep-indexed #(when (= \♗ %2) %1) rank))))))   (defn king-legal? "True if the king is between two rooks" [rank] (let [king-&-rooks (filter #{\♔ \♖} rank)] (and (= 3 (count king-&-rooks)) (= \u2654 (second king-&-rooks)))))     (defn c960 "Return a legal rank for c960 chess" ([] (c960 1)) ([n] (->> #(shuffle starting-rank) repeatedly (filter #(and (king-legal? %) (bishops-legal? %))) (take n) (map #(s/join ", " %)))))     (c960) ;; => "♗, ♖, ♔, ♕, ♘, ♘, ♖, ♗" (c960) ;; => "♖, ♕, ♘, ♔, ♗, ♗, ♘, ♖" (c960 4) ;; => ("♘, ♖, ♔, ♘, ♗, ♗, ♖, ♕" "♗, ♖, ♔, ♘, ♘, ♕, ♖, ♗" "♘, ♕, ♗, ♖, ♔, ♗, ♘, ♖" "♖, ♔, ♘, ♘, ♕, ♖, ♗, ♗")
http://rosettacode.org/wiki/Gapful_numbers
Gapful numbers
Numbers   (positive integers expressed in base ten)   that are (evenly) divisible by the number formed by the first and last digit are known as   gapful numbers. Evenly divisible   means divisible with   no   remainder. All   one─   and two─digit   numbers have this property and are trivially excluded.   Only numbers   ≥ 100   will be considered for this Rosetta Code task. Example 187   is a   gapful   number because it is evenly divisible by the number   17   which is formed by the first and last decimal digits of   187. About   7.46%   of positive integers are   gapful. Task   Generate and show all sets of numbers (below) on one line (horizontally) with a title,   here on this page   Show the first   30   gapful numbers   Show the first   15   gapful numbers   ≥          1,000,000   Show the first   10   gapful numbers   ≥   1,000,000,000 Related tasks   Harshad or Niven series.   palindromic gapful numbers.   largest number divisible by its digits. Also see   The OEIS entry:   A108343 gapful numbers.   numbersaplenty gapful numbers
#ALGOL_68
ALGOL 68
BEGIN # find some gapful numbers - numbers divisible by f*10 + b # # where f is the first digit and b is the final digit # # unary GAPFUL operator - returns TRUE if n is gapful # # FALSE otherwise # OP GAPFUL = ( INT n )BOOL: BEGIN INT abs n = ABS n; INT back = abs n MOD 10; # final digit # INT front := abs n OVER 10; WHILE front > 9 DO front OVERAB 10 OD; abs n MOD ( ( front * 10 ) + back ) = 0 END; # GAPFUL # # dyadic GAPFUL operator - returns an array of n gapful # # numbers starting from first # PRIO GAPFUL = 9; OP GAPFUL = ( INT n, INT first )[]INT: BEGIN [ 1 : n ]INT result; INT g pos := 0; FOR i FROM first WHILE g pos < n DO IF GAPFUL i THEN result[ g pos +:= 1 ] := i FI OD; result END; # GAPFUL # # prints a sequence of gapful numbers # PROC print gapful = ( []INT seq, INT start )VOID: BEGIN print( ( "First ", whole( ( UPB seq + 1 ) - LWB seq, 0 ) , " gapful numbers starting from ", whole( start, 0 ) , ":", newline ) ); FOR i FROM LWB seq TO UPB seq DO print( ( " ", whole( seq[ i ], 0 ) ) ) OD; print( ( newline ) ) END; # print gapful # print gapful( 30 GAPFUL 100, 100 ); print gapful( 15 GAPFUL 1 000 000, 1 000 000 ); print gapful( 10 GAPFUL 1 000 000 000, 1 000 000 000 ) END
http://rosettacode.org/wiki/Generate_random_chess_position
Generate random chess position
Task Generate a random chess position in FEN format. The position does not have to be realistic or even balanced,  but it must comply to the following rules: there is one and only one king of each color  (one black king and one white king); the kings must not be placed on adjacent squares; there can not be any pawn in the promotion square  (no white pawn in the eighth rank, and no black pawn in the first rank); including the kings, up to 32 pieces of either color can be placed. There is no requirement for material balance between sides. The picking of pieces does not have to comply to a regular chess set --- there can be five knights, twenty rooks, whatever ... as long as the total number of pieces do not exceed thirty-two. it is white's turn. It's assumed that both sides have lost castling rights and that there is no possibility for   en passant   (the FEN should thus end in w - - 0 1). No requirement is made regarding the probability distribution of your method, but your program should be able to span a reasonably representative sample of all possible positions. For instance, programs that would always generate positions with say five pieces on the board, or with kings on a corner, would not be considered truly random.
#J
J
getlayout=:3 :0 whilst. NB. first two positions are non-adjacent kings (0{pos) e. (1{pos)+(,-)1 7 8 9 do. pos=: y?64 end. )   randboard=:3 :0 n=: ?30 NB. number of non-king pieces on board layout=: getlayout 2+n NB. where they go white=: 0 1,?n#2 NB. which ones are white? pawns=: 0 0,?n#2 NB. where are the pawns? pawns=: pawns * 1- white*layout e.56+i.8 pawns=: pawns * 1-(1-white)*layout e.i.8 ptyp=: 'pkqbjnPKQBJN'{~(6*white)+1 1,(1-2}.pawns)*2+?n#4 8 8$ptyp layout}64#'.' )   NB. fen compress a line fen1=:3 :0 for_n.8-i.8 do. y=. y rplc (#&'.';":) n end. )   NB. translate 8x8 board to fen notation NB. (just the task specific crippled fen) b2fen=:3 :0 (}.;|.<@(('/',fen1)"1) y),' w - - 0 1' )   randfen=:b2fen@randboard
http://rosettacode.org/wiki/Gauss-Jordan_matrix_inversion
Gauss-Jordan matrix inversion
Task Invert matrix   A   using Gauss-Jordan method. A   being an   n × n   matrix.
#360_Assembly
360 Assembly
* Gauss-Jordan matrix inversion 17/01/2021 GAUSSJOR CSECT USING GAUSSJOR,R13 base register B 72(R15) skip savearea DC 17F'0' savearea SAVE (14,12) save previous context ST R13,4(R15) link backward ST R15,8(R13) link forward LR R13,R15 set addressability LA R6,1 i=1 DO WHILE=(C,R6,LE,N) do i=1 to n LA R7,1 j=1 DO WHILE=(C,R7,LE,N) do j=1 to n LR R1,R6 i BCTR R1,0 -1 MH R1,HN *n LR R0,R7 j BCTR R0,0 -1 AR R1,R0 (i-1)*n+j-1 SLA R1,2 *4 LE F0,AA(R1) aa(i,j) LR R1,R6 i BCTR R1,0 -1 MH R1,HN2 *n*2 LR R0,R7 j BCTR R0,0 -1 AR R1,R0 (i-1)*n*2+j-1 SLA R1,2 *4 STE F0,TMP(R1) tmp(i,j)=aa(i,j) LA R7,1(R7) j++ ENDDO , enddo j LA R7,1 j=1 A R7,N j=n+1 DO WHILE=(C,R7,LE,N2) do j=n+1 to 2*n LR R1,R6 i BCTR R1,0 -1 MH R1,HN2 *n*2 LR R0,R7 j BCTR R0,0 -1 AR R1,R0 (i-1)*n*2+j-1 SLA R1,2 *4 LE F0,=E'0' 0 STE F0,TMP(R1) tmp(i,j)=0 LA R7,1(R7) j++ ENDDO , enddo j LR R2,R6 i A R2,N i+n LR R1,R6 i BCTR R1,0 -1 MH R1,HN2 *n*2 BCTR R2,0 -1 AR R1,R2 (i+n-1)*n*2+i-1 SLA R1,2 *4 LE F0,=E'1' 1 STE F0,TMP(R1) tmp(i,i+n)=1 LA R6,1(R6) i++ ENDDO , enddo i LA R6,1 i=1 DO WHILE=(C,R6,LE,N) do r=1 to n LR R1,R6 r BCTR R1,0 -1 MH R1,HN2 *n*2 LR R0,R6 r BCTR R0,0 -1 AR R1,R0 (r-1)*n*2+r-1 SLA R1,2 *4 LE F0,TMP(R1) tmp(r,r) STE F0,T t=tmp(r,r) LA R7,1 c=1 DO WHILE=(C,R7,LE,N2) do c=1 to n*2 LR R1,R6 r BCTR R1,0 MH R1,HN2 LR R0,R7 c BCTR R0,0 AR R1,R0 SLA R1,2 LE F0,TMP(R1) LTER F0,F0 BZ *+8 DE F0,T tmp(r,c)/t LR R1,R6 r BCTR R1,0 MH R1,HN2 LR R0,R7 c BCTR R0,0 AR R1,R0 SLA R1,2 STE F0,TMP(R1) tmp(r,c)=tmp(r,c)/t LA R7,1(R7) c++ ENDDO , enddo c LA R8,1 i=1 DO WHILE=(C,R8,LE,N) do i=1 to n IF CR,R8,NE,R6 THEN if i^=r then LR R1,R8 i BCTR R1,0 MH R1,HN2 LR R0,R6 r BCTR R0,0 AR R1,R0 SLA R1,2 LE F0,TMP(R1) tmp(i,r) STE F0,T t=tmp(i,r) LA R7,1 c=1 DO WHILE=(C,R7,LE,N2) do c=1 to n*2 LR R2,R8 i BCTR R2,0 MH R2,HN2 LR R0,R7 c BCTR R0,0 AR R2,R0 SLA R2,2 LE F0,TMP(R2) f0=tmp(i,c) LR R1,R6 r BCTR R1,0 MH R1,HN2 LR R0,R7 c BCTR R0,0 AR R1,R0 SLA R1,2 LE F2,TMP(R1) f2=tmp(r,c) LE F4,T t MER F4,F2 f4=t*tmp(r,c) SER F0,F4 f0=tmp(i,c)-t*tmp(r,c) STE F0,TMP(R2) tmp(i,c)=f0 LA R7,1(R7) c++ ENDDO , enddo c ENDIF , endif LA R8,1(R8) i++ ENDDO , enddo i LA R6,1(R6) r++ ENDDO , enddo r LA R6,1 i=1 DO WHILE=(C,R6,LE,N) do i=1 to n L R7,N n LA R7,1(R7) j=n+1 DO WHILE=(C,R7,LE,N2) do j=n+1 to 2*n LR R2,R7 j S R2,N -n LR R1,R6 i BCTR R1,0 MH R1,HN2 *2*n LR R0,R7 j BCTR R0,0 AR R1,R0 SLA R1,2 LE F0,TMP(R1) tmp(i,j) LR R1,R6 i BCTR R1,0 MH R1,HN *n BCTR R2,0 AR R1,R2 SLA R1,2 STE F0,BB(R1) bb(i,j-n)=tmp(i,j) LA R7,1(R7) j++ ENDDO , enddo j LA R6,1(R6) i++ ENDDO , enddo i LA R6,1 i=1 DO WHILE=(C,R6,LE,N) do i=1 to n LA R3,PG @pg LA R7,1 j=1 DO WHILE=(C,R7,LE,N) do j=1 to n LR R1,R6 i BCTR R1,0 MH R1,HN *n LR R0,R7 j BCTR R0,0 AR R1,R0 SLA R1,2 LE F0,BB(R1) bb(i,j) LA R0,5 number of decimals BAL R14,FORMATF FormatF(bb(i,j)) MVC 0(13,R3),0(R1) edit LA R3,13(R3) @pg+=13 LA R7,1(R7) j++ ENDDO , enddo j XPRNT PG,L'PG print buffer LA R6,1(R6) i++ ENDDO , enddo i L R13,4(0,R13) restore previous savearea pointer RETURN (14,12),RC=0 restore registers from calling save COPY plig\$_FORMATF.MLC format a float NN EQU 5 N DC A(NN) N2 DC A(NN*2) AA DC E'3.0',E'1.0',E'5.0',E'9.0',E'7.0' DC E'8.0',E'2.0',E'8.0',E'0.0',E'1.0' DC E'1.0',E'7.0',E'2.0',E'0.0',E'3.0' DC E'0.0',E'1.0',E'7.0',E'0.0',E'9.0' DC E'3.0',E'5.0',E'6.0',E'1.0',E'1.0' BB DS (NN*NN)E TMP DS (NN*NN*2)E T DS E HN DC AL2(NN) HN2 DC AL2(NN*2) PG DC CL80' ' buffer REGEQU END GAUSSJOR
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#AWK
AWK
105 3 Fizz 5 Buzz 7 Baxx
http://rosettacode.org/wiki/General_FizzBuzz
General FizzBuzz
Task Write a generalized version of FizzBuzz that works for any list of factors, along with their words. This is basically a "fizzbuzz" implementation where the user supplies the parameters. The user will enter the max number, then they will enter the factors to be calculated along with the corresponding word to be printed. For simplicity's sake, assume the user will input an integer as the max number and 3 factors, each with a word associated with them. For example, given: >20 #This is the maximum number, supplied by the user >3 Fizz #The user now enters the starting factor (3) and the word they want associated with it (Fizz) >5 Buzz #The user now enters the next factor (5) and the word they want associated with it (Buzz) >7 Baxx #The user now enters the next factor (7) and the word they want associated with it (Baxx) In other words: For this example, print the numbers 1 through 20, replacing every multiple of 3 with "Fizz", every multiple of 5 with "Buzz", and every multiple of 7 with "Baxx". In the case where a number is a multiple of at least two factors, print each of the words associated with those factors in the order of least to greatest factor. For instance, the number 15 is a multiple of both 3 and 5; print "FizzBuzz". If the max number was 105 instead of 20, you would print "FizzBuzzBaxx" because it's a multiple of 3, 5, and 7. Output: 1 2 Fizz 4 Buzz Fizz Baxx 8 Fizz Buzz 11 Fizz 13 Baxx FizzBuzz 16 17 Fizz 19 Buzz
#Batch_File
Batch File
@echo off rem input range set /p "range=> " rem input data (no error-checking) set "data_ctr=0" :input_loop set "data=" set /p "data=> " if "%data%" equ "" goto count rem parsing data into 1-based pseudo-array set /a "data_ctr+=1" for /f "tokens=1-2 delims= " %%D in ("%data%") do ( set "facto%data_ctr%=%%D" set "print%data_ctr%=%%E" ) goto input_loop rem perform fizzbuzz now :count setlocal enabledelayedexpansion for /l %%C in (1,1,%range%) do ( set "out=" for /l %%X in (1,1,%data_ctr%) do ( set /a "mod=%%C %% facto%%X" if !mod! equ 0 set "out=!out!!print%%X!" ) if not defined out (echo %%C) else (echo !out!) ) pause exit /b 0
http://rosettacode.org/wiki/Hailstone_sequence
Hailstone sequence
The Hailstone sequence of numbers can be generated from a starting positive integer,   n   by:   If   n   is     1     then the sequence ends.   If   n   is   even then the next   n   of the sequence   = n/2   If   n   is   odd   then the next   n   of the sequence   = (3 * n) + 1 The (unproven) Collatz conjecture is that the hailstone sequence for any starting number always terminates. This sequence was named by Lothar Collatz in 1937   (or possibly in 1939),   and is also known as (the):   hailstone sequence,   hailstone numbers   3x + 2 mapping,   3n + 1 problem   Collatz sequence   Hasse's algorithm   Kakutani's problem   Syracuse algorithm,   Syracuse problem   Thwaites conjecture   Ulam's problem The hailstone sequence is also known as   hailstone numbers   (because the values are usually subject to multiple descents and ascents like hailstones in a cloud). Task Create a routine to generate the hailstone sequence for a number. Use the routine to show that the hailstone sequence for the number 27 has 112 elements starting with 27, 82, 41, 124 and ending with 8, 4, 2, 1 Show the number less than 100,000 which has the longest hailstone sequence together with that sequence's length.   (But don't show the actual sequence!) See also   xkcd (humourous).   The Notorious Collatz conjecture Terence Tao, UCLA (Presentation, pdf).   The Simplest Math Problem No One Can Solve Veritasium (video, sponsored).
#Swift
Swift
  func hailstone(var n:Int) -> [Int] {   var arr = [n]   while n != 1 {   if n % 2 == 0 { n /= 2 } else { n = (3 * n) + 1 }   arr.append(n) }   return arr }   let n = hailstone(27)   println("hailstone(27): \(n[0...3]) ... \(n[n.count-4...n.count-1]) for a count of \(n.count).")   var longest = (n: 1, len: 1)   for i in 1...100_000 {   let new = hailstone(i)   if new.count > longest.len { longest = (i, new.count) } }   println("Longest sequence for numbers under 100,000 is with \(longest.n). Which has \(longest.len) items.")
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet
Generate lower case ASCII alphabet
Task Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence. For this basic task use a reliable style of coding, a style fit for a very large program, and use strong typing if available. It's bug prone to enumerate all the lowercase characters manually in the code. During code review it's not immediate obvious to spot the bug in a Tcl line like this contained in a page of code: set alpha {a b c d e f g h i j k m n o p q r s t u v w x y z} 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
L$="abcdefghijklmnopqrstuvwxyz"