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http://rosettacode.org/wiki/Brownian_tree
Brownian tree
Brownian tree You are encouraged to solve this task according to the task description, using any language you may know. Task Generate and draw a   Brownian Tree. A Brownian Tree is generated as a result of an initial seed, followed by the interaction of two processes. The initial "seed" is placed somewhere within the field. Where is not particularly important; it could be randomized, or it could be a fixed point. Particles are injected into the field, and are individually given a (typically random) motion pattern. When a particle collides with the seed or tree, its position is fixed, and it's considered to be part of the tree. Because of the lax rules governing the random nature of the particle's placement and motion, no two resulting trees are really expected to be the same, or even necessarily have the same general shape.
#Sinclair_ZX81_BASIC
Sinclair ZX81 BASIC
10 DIM A$(20,20) 20 LET A$(10,10)="1" 30 FOR Y=42 TO 23 STEP -1 40 FOR X=0 TO 19 50 PLOT X,Y 60 NEXT X 70 NEXT Y 80 UNPLOT 9,33 90 FOR I=1 TO 80 100 LET X=INT (RND*18)+2 110 LET Y=INT (RND*18)+2 120 IF A$(X,Y)="1" THEN GOTO 100 130 UNPLOT X-1,43-Y 140 IF A$(X+1,Y+1)="1" OR A$(X+1,Y)="1" OR A$(X+1,Y-1)="1" OR A$(X,Y+1)="1" OR A$(X,Y-1)="1" OR A$(X-1,Y+1)="1" OR A$(X-1,Y)="1" OR A$(X-1,Y-1)="1" THEN GOTO 230 150 PLOT X-1,43-Y 160 LET X=X+INT (RND*3)-1 170 LET Y=Y+INT (RND*3)-1 180 IF X=1 THEN LET X=19 190 IF X=20 THEN LET X=2 200 IF Y=1 THEN LET Y=19 210 IF Y=20 THEN LET Y=2 220 GOTO 130 230 LET A$(X,Y)="1" 240 NEXT I
http://rosettacode.org/wiki/Brownian_tree
Brownian tree
Brownian tree You are encouraged to solve this task according to the task description, using any language you may know. Task Generate and draw a   Brownian Tree. A Brownian Tree is generated as a result of an initial seed, followed by the interaction of two processes. The initial "seed" is placed somewhere within the field. Where is not particularly important; it could be randomized, or it could be a fixed point. Particles are injected into the field, and are individually given a (typically random) motion pattern. When a particle collides with the seed or tree, its position is fixed, and it's considered to be part of the tree. Because of the lax rules governing the random nature of the particle's placement and motion, no two resulting trees are really expected to be the same, or even necessarily have the same general shape.
#Tcl
Tcl
package require Tcl 8.5 package require Tk   set SIZE 300   image create photo brownianTree -width $SIZE -height $SIZE interp alias {} plot {} brownianTree put white -to brownianTree put black -to 0 0 [expr {$SIZE-1}] [expr {$SIZE-1}] proc rnd {range} {expr {int(rand() * $range)}}   proc makeBrownianTree count { global SIZE # Set the seed plot [rnd $SIZE] [rnd $SIZE] for {set i 0} {$i<$count} {incr i} { # Set a random particle's initial position set px [rnd $SIZE] set py [rnd $SIZE]   while 1 { # Randomly choose a direction set dx [expr {[rnd 3] - 1}] set dy [expr {[rnd 3] - 1}]   # If we are going out of bounds... if {$px+$dx < 0 || $px+$dx >= $SIZE || $py+$dy < 0 || $py+$dy>=$SIZE} { # Out of bounds, so move back in set dx [expr {[rnd 3] - 1}] set dy [expr {[rnd 3] - 1}] continue }   set ox $px set oy $py # Move/see if we would hit anything incr px $dx incr py $dy if {[lindex [brownianTree get $px $py] 0]} { # Hit something, so plot where we were plot $ox $oy break } } ## For display while things are processing, uncomment next line #update;puts -nonewline .;flush stdout } }   pack [label .l -image brownianTree] update makeBrownianTree 1000 brownianTree write tree.ppm
http://rosettacode.org/wiki/Bulls_and_cows
Bulls and cows
Bulls and Cows Task Create a four digit random number from the digits   1   to   9,   without duplication. The program should:   ask for guesses to this number   reject guesses that are malformed   print the score for the guess The score is computed as: The player wins if the guess is the same as the randomly chosen number, and the program ends. A score of one bull is accumulated for each digit in the guess that equals the corresponding digit in the randomly chosen initial number. A score of one cow is accumulated for each digit in the guess that also appears in the randomly chosen number, but in the wrong position. Related tasks   Bulls and cows/Player   Guess the number   Guess the number/With Feedback   Mastermind
#Lua
Lua
function ShuffleArray(array) for i=1,#array-1 do local t = math.random(i, #array) array[i], array[t] = array[t], array[i] end end   function GenerateNumber() local digits = {1,2,3,4,5,6,7,8,9}   ShuffleArray(digits)   return digits[1] * 1000 + digits[2] * 100 + digits[3] * 10 + digits[4] end   function IsMalformed(input) local malformed = false   if #input == 4 then local already_used = {} for i=1,4 do local digit = input:byte(i) - string.byte('0') if digit < 1 or digit > 9 or already_used[digit] then malformed = true break end already_used[digit] = true end else malformed = true end   return malformed end   math.randomseed(os.time()) math.randomseed(math.random(2^31-1)) -- since os.time() only returns seconds   print("\nWelcome to Bulls and Cows!") print("") print("The object of this game is to guess the random 4-digit number that the") print("computer has chosen. The number is generated using only the digits 1-9,") print("with no repeated digits. Each time you enter a guess, you will score one") print("\"bull\" for each digit in your guess that matches the corresponding digit") print("in the computer-generated number, and you will score one \"cow\" for each") print("digit in your guess that appears in the computer-generated number, but is") print("in the wrong position. Use this information to refine your guesses. When") print("you guess the correct number, you win."); print("")   quit = false   repeat magic_number = GenerateNumber() magic_string = tostring(magic_number) -- Easier to do scoring with a string repeat io.write("\nEnter your guess (or 'Q' to quit): ") user_input = io.read() if user_input == 'Q' or user_input == 'q' then quit = true break end   if not IsMalformed(user_input) then if user_input == magic_string then print("YOU WIN!!!") else local bulls, cows = 0, 0 for i=1,#user_input do local find_result = magic_string:find(user_input:sub(i,i))   if find_result and find_result == i then bulls = bulls + 1 elseif find_result then cows = cows + 1 end end print(string.format("You scored %d bulls, %d cows", bulls, cows)) end else print("Malformed input. You must enter a 4-digit number with") print("no repeated digits, using only the digits 1-9.") end   until user_input == magic_string   if not quit then io.write("\nPress <Enter> to play again or 'Q' to quit: ") user_input = io.read() if user_input == 'Q' or user_input == 'q' then quit = true end end   if quit then print("\nGoodbye!") end until quit
http://rosettacode.org/wiki/Caesar_cipher
Caesar cipher
Task Implement a Caesar cipher, both encoding and decoding. The key is an integer from 1 to 25. This cipher rotates (either towards left or right) the letters of the alphabet (A to Z). The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A). So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC". This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys. Caesar cipher is identical to Vigenère cipher with a key of length 1. Also, Rot-13 is identical to Caesar cipher with key 13. Related tasks Rot-13 Substitution Cipher Vigenère Cipher/Cryptanalysis
#Groovy
Groovy
def caesarEncode(​cipherKey, text) { def builder = new StringBuilder() text.each { character -> int ch = character[0] as char switch(ch) { case 'a'..'z': ch = ((ch - 97 + cipherKey) % 26 + 97); break case 'A'..'Z': ch = ((ch - 65 + cipherKey) % 26 + 65); break } builder << (ch as char) } builder as String } def caesarDecode(cipherKey, text) { caesarEncode(26 - cipherKey, text) }
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#Oforth
Oforth
a b c f
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#Ol
Ol
  ; note: sign "==>" indicates expected output   ;;; Calling a function that requires no arguments (define (no-args-function) (print "ok."))   (no-args-function) ; ==> ok.     ;;; Calling a function with a fixed number of arguments (define (two-args-function a b) (print "a: " a) (print "b: " b))   (two-args-function 8 13) ; ==> a: 8 ; ==> b: 13     ;;; Calling a function with optional arguments (define (optional-args-function a . args) (print "a: " a) (if (null? args) (print "no optional arguments")) (if (less? 0 (length args)) (print "b: " (car args))) (if (less? 1 (length args)) (print "c: " (cadr args))) ; etc... )   (optional-args-function 3) ; ==> a: 3 ; ==> no optional arguments (optional-args-function 3 8) ; ==> a: 3 ; ==> b: 8 (optional-args-function 3 8 13) ; ==> a: 3 ; ==> b: 8 ; ==> c: 13 (optional-args-function 3 8 13 77) ; ==> a: 3 ; ==> b: 8 ; ==> c: 13     ;;; Calling a function with a variable number of arguments ; /same as optional arguments     ;;; Calling a function with named arguments ; /no named arguments "from the box" is provided, but it can be easily simulated using builtin associative arrays (named "ff") (define (named-args-function args) (print "a: " (get args 'a 8)) ; 8 is default value if no variable value given (print "b: " (get args 'b 13)); same as above )   (named-args-function #empty) ; ==> a: 8 ; ==> b: 13 (named-args-function (list->ff '((a . 3)))) ; ==> a: 3 ; ==> b: 13 ; or nicer (and shorter) form available from ol version 2.1 (named-args-function '{a 3}) ; ==> a: 3 ; ==> b: 13 (named-args-function '{b 7}) ; ==> a: 8 ; ==> b: 7 (named-args-function '{a 3 b 7}) ; ==> a: 3 ; ==> b: 7     ;;; Using a function in first-class context within an expression (define (first-class-arg-function arg a b) (print (arg a b)) )   (first-class-arg-function + 2 3) ; ==> 5 (first-class-arg-function - 2 3) ; ==> -1   ;;; Using a function in statement context (let ((function (lambda (x) (* x x)))) (print (function 4)) ; ==> 16 ;(print (function 4)) ; ==> What is 'function'?   ;;; Obtaining the return value of a function (define (return-value-function) (print "ok.") 123)   (let ((result (return-value-function))) (print result)) ; ==> ok. ; ==> 123   ;;; Obtaining the return value of a function while breaking the function execution (for example infinite loop) (print (call/cc (lambda (return) (let loop ((n 0)) (if (eq? n 100) (return (* n n))) (loop (+ n 1))))))) ; this is infinite loop ; ==> 10000     ;;; Is partial application possible and how (define (make-partial-function n) (lambda (x y) (print (n x y))) )   (define plus (make-partial-function +)) (define minus (make-partial-function -))   (plus 2 3) ; ==> 5 (minus 2 3) ; ==> -1   ;;; Distinguishing built-in functions and user-defined functions ; ol has no builtin functions but only eight builtin forms: quote, values, lambda, setq, letq, ifeq, either, values-apply. ; all other functions is "user-defined", and some of them defined in base library, for example (scheme core) defines if, or, and, zero?, length, append...   ;;; Distinguishing subroutines and functions ; Both subroutines and functions is a functions in Ol. ; Btw, the "subroutine" has a different meaning in Ol - the special function that executes simultaneously in own context. The intersubroutine messaging mechanism is provided, sure.   ;;; Stating whether arguments are passed by value or by reference ; The values in Ol always passed as values and objects always passed as references. If you want to pass an object copy - make a copy by yourself.  
http://rosettacode.org/wiki/Catalan_numbers
Catalan numbers
Catalan numbers You are encouraged to solve this task according to the task description, using any language you may know. Catalan numbers are a sequence of numbers which can be defined directly: C n = 1 n + 1 ( 2 n n ) = ( 2 n ) ! ( n + 1 ) ! n !  for  n ≥ 0. {\displaystyle C_{n}={\frac {1}{n+1}}{2n \choose n}={\frac {(2n)!}{(n+1)!\,n!}}\qquad {\mbox{ for }}n\geq 0.} Or recursively: C 0 = 1 and C n + 1 = ∑ i = 0 n C i C n − i for  n ≥ 0 ; {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n+1}=\sum _{i=0}^{n}C_{i}\,C_{n-i}\quad {\text{for }}n\geq 0;} Or alternatively (also recursive): C 0 = 1 and C n = 2 ( 2 n − 1 ) n + 1 C n − 1 , {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n}={\frac {2(2n-1)}{n+1}}C_{n-1},} Task Implement at least one of these algorithms and print out the first 15 Catalan numbers with each. Memoization   is not required, but may be worth the effort when using the second method above. Related tasks Catalan numbers/Pascal's triangle Evaluate binomial coefficients
#Raku
Raku
constant Catalan = 1, { [+] @_ Z* @_.reverse } ... *;
http://rosettacode.org/wiki/Calendar
Calendar
Create a routine that will generate a text calendar for any year. Test the calendar by generating a calendar for the year 1969, on a device of the time. Choose one of the following devices: A line printer with a width of 132 characters. An IBM 3278 model 4 terminal (80×43 display with accented characters). Target formatting the months of the year to fit nicely across the 80 character width screen. Restrict number of lines in test output to 43. (Ideally, the program will generate well-formatted calendars for any page width from 20 characters up.) Kudos (κῦδος) for routines that also transition from Julian to Gregorian calendar. This task is inspired by Real Programmers Don't Use PASCAL by Ed Post, Datamation, volume 29 number 7, July 1983. THE REAL PROGRAMMER'S NATURAL HABITAT "Taped to the wall is a line-printer Snoopy calender for the year 1969." For further Kudos see task CALENDAR, where all code is to be in UPPERCASE. For economy of size, do not actually include Snoopy generation in either the code or the output, instead just output a place-holder. Related task   Five weekends
#Python
Python
>>> import calendar >>> help(calendar.prcal) Help on method pryear in module calendar:   pryear(self, theyear, w=0, l=0, c=6, m=3) method of calendar.TextCalendar instance Print a years calendar.   >>> calendar.prcal(1969) 1969   January February March Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su 1 2 3 4 5 1 2 1 2 6 7 8 9 10 11 12 3 4 5 6 7 8 9 3 4 5 6 7 8 9 13 14 15 16 17 18 19 10 11 12 13 14 15 16 10 11 12 13 14 15 16 20 21 22 23 24 25 26 17 18 19 20 21 22 23 17 18 19 20 21 22 23 27 28 29 30 31 24 25 26 27 28 24 25 26 27 28 29 30 31   April May June Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su 1 2 3 4 5 6 1 2 3 4 1 7 8 9 10 11 12 13 5 6 7 8 9 10 11 2 3 4 5 6 7 8 14 15 16 17 18 19 20 12 13 14 15 16 17 18 9 10 11 12 13 14 15 21 22 23 24 25 26 27 19 20 21 22 23 24 25 16 17 18 19 20 21 22 28 29 30 26 27 28 29 30 31 23 24 25 26 27 28 29 30   July August September Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su 1 2 3 4 5 6 1 2 3 1 2 3 4 5 6 7 7 8 9 10 11 12 13 4 5 6 7 8 9 10 8 9 10 11 12 13 14 14 15 16 17 18 19 20 11 12 13 14 15 16 17 15 16 17 18 19 20 21 21 22 23 24 25 26 27 18 19 20 21 22 23 24 22 23 24 25 26 27 28 28 29 30 31 25 26 27 28 29 30 31 29 30   October November December Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su 1 2 3 4 5 1 2 1 2 3 4 5 6 7 6 7 8 9 10 11 12 3 4 5 6 7 8 9 8 9 10 11 12 13 14 13 14 15 16 17 18 19 10 11 12 13 14 15 16 15 16 17 18 19 20 21 20 21 22 23 24 25 26 17 18 19 20 21 22 23 22 23 24 25 26 27 28 27 28 29 30 31 24 25 26 27 28 29 30 29 30 31
http://rosettacode.org/wiki/Brownian_tree
Brownian tree
Brownian tree You are encouraged to solve this task according to the task description, using any language you may know. Task Generate and draw a   Brownian Tree. A Brownian Tree is generated as a result of an initial seed, followed by the interaction of two processes. The initial "seed" is placed somewhere within the field. Where is not particularly important; it could be randomized, or it could be a fixed point. Particles are injected into the field, and are individually given a (typically random) motion pattern. When a particle collides with the seed or tree, its position is fixed, and it's considered to be part of the tree. Because of the lax rules governing the random nature of the particle's placement and motion, no two resulting trees are really expected to be the same, or even necessarily have the same general shape.
#TI-83_BASIC
TI-83 BASIC
:StoreGDB 0 :ClrDraw :FnOff :AxesOff :Pxl-On(31,47) :For(I,1,50) :randInt(1,93)→X :randInt(1,61)→Y :1→A :While A :randInt(1,4)→D :Pxl-Off(Y,X) :If D=1 and Y≥2 :Y-1→Y :If D=2 and X≤92 :X+1→X :If D=3 and Y≤60 :Y+1→Y :If D=4 and X≥2 :X-1→X :Pxl-On(Y,X) :If pxl-Test(Y+1,X) or pxl-Test(Y+1,X+1) or pxl-Test(Y+1,X-1) or pxl-Test(Y,X+1) or pxl-Test(Y,X-1) or pxl-Test(Y-1,X) or pxl-Test(Y-1,X-1) or pxl-Test(Y-1,X+1) :0→A :End :End :Pause :RecallGDB 0
http://rosettacode.org/wiki/Brownian_tree
Brownian tree
Brownian tree You are encouraged to solve this task according to the task description, using any language you may know. Task Generate and draw a   Brownian Tree. A Brownian Tree is generated as a result of an initial seed, followed by the interaction of two processes. The initial "seed" is placed somewhere within the field. Where is not particularly important; it could be randomized, or it could be a fixed point. Particles are injected into the field, and are individually given a (typically random) motion pattern. When a particle collides with the seed or tree, its position is fixed, and it's considered to be part of the tree. Because of the lax rules governing the random nature of the particle's placement and motion, no two resulting trees are really expected to be the same, or even necessarily have the same general shape.
#Visual_Basic_.NET
Visual Basic .NET
  Imports System.Drawing.Imaging   Public Class Form1   ReadOnly iCanvasColor As Integer = Color.Black.ToArgb ReadOnly iSeedColor As Integer = Color.White.ToArgb   Dim iCanvasWidth As Integer = 0 Dim iCanvasHeight As Integer = 0   Dim iPixels() As Integer = Nothing   Private Sub BrownianTree()   Dim oCanvas As Bitmap = Nothing Dim oRandom As New Random(Now.Millisecond) Dim oXY As Point = Nothing Dim iParticleCount As Integer = 0   iCanvasWidth = ClientSize.Width iCanvasHeight = ClientSize.Height   oCanvas = New Bitmap(iCanvasWidth, iCanvasHeight, Imaging.PixelFormat.Format24bppRgb)   Graphics.FromImage(oCanvas).Clear(Color.FromArgb(iCanvasColor))   iPixels = GetData(oCanvas)   ' We'll use about 10% of the total number of pixels in the canvas for the particle count. iParticleCount = CInt(iPixels.Length * 0.1)   ' Set the seed to a random location on the canvas. iPixels(oRandom.Next(iPixels.Length)) = iSeedColor   ' Run through the particles. For i As Integer = 0 To iParticleCount Do ' Find an open pixel. oXY = New Point(oRandom.Next(oCanvas.Width), oRandom.Next(oCanvas.Height)) Loop While iPixels(oXY.Y * oCanvas.Width + oXY.X) = iSeedColor   ' Jitter until the pixel bumps another. While Not CheckAdjacency(oXY) oXY.X += oRandom.Next(-1, 2) oXY.Y += oRandom.Next(-1, 2)   ' Make sure we don't jitter ourselves out of bounds. If oXY.X < 0 Then oXY.X = 0 Else If oXY.X >= oCanvas.Width Then oXY.X = oCanvas.Width - 1 If oXY.Y < 0 Then oXY.Y = 0 Else If oXY.Y >= oCanvas.Height Then oXY.Y = oCanvas.Height - 1 End While   iPixels(oXY.Y * oCanvas.Width + oXY.X) = iSeedColor   ' If you'd like to see updates as each particle collides and becomes ' part of the tree, uncomment the next 4 lines (it does slow it down slightly). ' SetData(oCanvas, iPixels) ' BackgroundImage = oCanvas ' Invalidate() ' Application.DoEvents() Next   oCanvas.Save("BrownianTree.bmp") BackgroundImage = oCanvas   End Sub   ' Check adjacent pixels for an illuminated pixel. Private Function CheckAdjacency(ByVal XY As Point) As Boolean   Dim n As Integer = 0   For y As Integer = -1 To 1 ' Make sure not to drop off the top or bottom of the image. If (XY.Y + y < 0) OrElse (XY.Y + y >= iCanvasHeight) Then Continue For   For x As Integer = -1 To 1 ' Make sure not to drop off the left or right of the image. If (XY.X + x < 0) OrElse (XY.X + x >= iCanvasWidth) Then Continue For   ' Don't run the test on the calling pixel. If y <> 0 AndAlso x <> 0 Then n = (XY.Y + y) * iCanvasWidth + (XY.X + x) If iPixels(n) = iSeedColor Then Return True End If Next Next   Return False   End Function   Private Function GetData(ByVal Map As Bitmap) As Integer()   Dim oBMPData As BitmapData = Nothing Dim oData() As Integer = Nothing   oBMPData = Map.LockBits(New Rectangle(0, 0, Map.Width, Map.Height), ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb)   Array.Resize(oData, Map.Width * Map.Height)   Runtime.InteropServices.Marshal.Copy(oBMPData.Scan0, oData, 0, oData.Length)   Map.UnlockBits(oBMPData)   Return oData   End Function   Private Sub SetData(ByVal Map As Bitmap, ByVal Data As Integer())   Dim oBMPData As BitmapData = Nothing   oBMPData = Map.LockBits(New Rectangle(0, 0, Map.Width, Map.Height), ImageLockMode.WriteOnly, PixelFormat.Format32bppArgb)   Runtime.InteropServices.Marshal.Copy(Data, 0, oBMPData.Scan0, Data.Length)   Map.UnlockBits(oBMPData)   End Sub   Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load DoubleBuffered = True BackgroundImageLayout = ImageLayout.Center Show() Activate() Application.DoEvents() BrownianTree() End Sub End Class  
http://rosettacode.org/wiki/Bulls_and_cows
Bulls and cows
Bulls and Cows Task Create a four digit random number from the digits   1   to   9,   without duplication. The program should:   ask for guesses to this number   reject guesses that are malformed   print the score for the guess The score is computed as: The player wins if the guess is the same as the randomly chosen number, and the program ends. A score of one bull is accumulated for each digit in the guess that equals the corresponding digit in the randomly chosen initial number. A score of one cow is accumulated for each digit in the guess that also appears in the randomly chosen number, but in the wrong position. Related tasks   Bulls and cows/Player   Guess the number   Guess the number/With Feedback   Mastermind
#M2000_Interpreter
M2000 Interpreter
  Module Game { Malformed=lambda (a$)->{ =true if len(a$)<>4 then exit n=0 : dummy=val(a$,"int",n) if n<>5 or dummy=0 then exit for i=1 to 9 if len(filter$(a$,str$(i,0)))<3 then break next i =false } BullsAndCows$=lambda$ (a$, b$, &ok) ->{ Def b, c for i=1 to 4 if mid$(a$,i,1)=mid$(b$,i,1) then b++ else.if instr(b$,mid$(a$,i,1))>0 then c++ end if next i ok=b=4 =format$("bulls {0}, cows {1}", b, c) } Random$=lambda$ ->{ def repl$, bank$, c$ bank$="123456789" for i=1 to 4 c$=mid$(bank$,random(1,len(bank$)),1) bank$=filter$(bank$, c$) repl$+=c$ next i =repl$ } target$=Random$() def boolean win=false, a$ do do Input "Next guess ";a% a$=str$(a%,0) if Malformed(a$) then Print "Malformed input, try again" else exit always Print BullsAndCows$(a$, target$, &win) if win then exit Print "Bad guess! (4 unique digits, 1-9)" always Print "You guess it" } Game  
http://rosettacode.org/wiki/Caesar_cipher
Caesar cipher
Task Implement a Caesar cipher, both encoding and decoding. The key is an integer from 1 to 25. This cipher rotates (either towards left or right) the letters of the alphabet (A to Z). The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A). So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC". This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys. Caesar cipher is identical to Vigenère cipher with a key of length 1. Also, Rot-13 is identical to Caesar cipher with key 13. Related tasks Rot-13 Substitution Cipher Vigenère Cipher/Cryptanalysis
#Haskell
Haskell
module Caesar (caesar, uncaesar) where   import Data.Char   caesar, uncaesar :: (Integral a) => a -> String -> String caesar k = map f where f c = case generalCategory c of LowercaseLetter -> addChar 'a' k c UppercaseLetter -> addChar 'A' k c _ -> c uncaesar k = caesar (-k)   addChar :: (Integral a) => Char -> a -> Char -> Char addChar b o c = chr $ fromIntegral (b' + (c' - b' + o) `mod` 26) where b' = fromIntegral $ ord b c' = fromIntegral $ ord c
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#ooRexx
ooRexx
say 'DATE'() Say date() Exit daTe: Return 'my date'
http://rosettacode.org/wiki/Catalan_numbers
Catalan numbers
Catalan numbers You are encouraged to solve this task according to the task description, using any language you may know. Catalan numbers are a sequence of numbers which can be defined directly: C n = 1 n + 1 ( 2 n n ) = ( 2 n ) ! ( n + 1 ) ! n !  for  n ≥ 0. {\displaystyle C_{n}={\frac {1}{n+1}}{2n \choose n}={\frac {(2n)!}{(n+1)!\,n!}}\qquad {\mbox{ for }}n\geq 0.} Or recursively: C 0 = 1 and C n + 1 = ∑ i = 0 n C i C n − i for  n ≥ 0 ; {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n+1}=\sum _{i=0}^{n}C_{i}\,C_{n-i}\quad {\text{for }}n\geq 0;} Or alternatively (also recursive): C 0 = 1 and C n = 2 ( 2 n − 1 ) n + 1 C n − 1 , {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n}={\frac {2(2n-1)}{n+1}}C_{n-1},} Task Implement at least one of these algorithms and print out the first 15 Catalan numbers with each. Memoization   is not required, but may be worth the effort when using the second method above. Related tasks Catalan numbers/Pascal's triangle Evaluate binomial coefficients
#REXX
REXX
/*REXX program calculates and displays Catalan numbers using four different methods. */ parse arg LO HI . /*obtain optional arguments from the CL*/ if LO=='' | LO=="," then do; HI=15; LO=0; end /*No args? Then use a range of 0 ──► 15*/ if HI=='' | HI=="," then HI=LO /*No HI? Then use LO for the default*/ numeric digits max(20, 5*HI) /*this allows gihugic Catalan numbers. */ w=length(HI) /*W: is used for aligning the output. */ call hdr 1A; do j=LO to HI; say ' Catalan' right(j, w)": " Cat1A(j); end call hdr 1B; do j=LO to HI; say ' Catalan' right(j, w)": " Cat1B(j); end call hdr 2 ; do j=LO to HI; say ' Catalan' right(j, w)": " Cat2(j) ; end call hdr 3 ; do j=LO to HI; say ' Catalan' right(j, w)": " Cat3(j) ; end exit /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ !: arg z; if !.z\==. then return !.z; !=1; do k=2 to z; !=!*k; end;  !.z=!; return ! Cat1A: procedure expose !.; parse arg n; return comb(n+n, n)  % (n+1) Cat1B: procedure expose !.; parse arg n; return !(n+n) % ((n+1) * !(n)**2) Cat3: procedure expose c.; arg n; if c.n==. then c.n=(4*n-2)*cat3(n-1)%(n+1); return c.n comb: procedure; parse arg x,y; return pFact(x-y+1, x) % pFact(2, y) hdr:  !.=.; c.=.; c.0=1; say; say center('Catalan numbers, method' arg(1),79,'─'); return pFact: procedure;  !=1; do k=arg(1) to arg(2);  !=!*k; end; return ! /*──────────────────────────────────────────────────────────────────────────────────────*/ Cat2: procedure expose c.; parse arg n; $=0; if c.n\==. then return c.n do k=0 for n; $=$ + Cat2(k) * Cat2(n-k-1); end c.n=$; return $ /*use a memoization technique.*/
http://rosettacode.org/wiki/Calendar
Calendar
Create a routine that will generate a text calendar for any year. Test the calendar by generating a calendar for the year 1969, on a device of the time. Choose one of the following devices: A line printer with a width of 132 characters. An IBM 3278 model 4 terminal (80×43 display with accented characters). Target formatting the months of the year to fit nicely across the 80 character width screen. Restrict number of lines in test output to 43. (Ideally, the program will generate well-formatted calendars for any page width from 20 characters up.) Kudos (κῦδος) for routines that also transition from Julian to Gregorian calendar. This task is inspired by Real Programmers Don't Use PASCAL by Ed Post, Datamation, volume 29 number 7, July 1983. THE REAL PROGRAMMER'S NATURAL HABITAT "Taped to the wall is a line-printer Snoopy calender for the year 1969." For further Kudos see task CALENDAR, where all code is to be in UPPERCASE. For economy of size, do not actually include Snoopy generation in either the code or the output, instead just output a place-holder. Related task   Five weekends
#Racket
Racket
#lang racket (require racket/date net/base64 file/gunzip) (define (calendar yr) (define (nsplit n l) (if (null? l) l (cons (take l n) (nsplit n (drop l n))))) (define months (for/list ([mn (in-naturals 1)] [mname '(January February March April May June July August September October November December)]) (define s (find-seconds 0 0 12 1 mn yr)) (define pfx (date-week-day (seconds->date s))) (define days (let ([? (if (= mn 12) (λ(x y) y) (λ(x y) x))]) (round (/ (- (find-seconds 0 0 12 1 (? (+ 1 mn) 1) (? yr (+ 1 yr))) s) 60 60 24)))) (list* (~a mname #:width 20 #:align 'center) "Su Mo Tu We Th Fr Sa" (map string-join (nsplit 7 `(,@(make-list pfx " ") ,@(for/list ([d days]) (~a (+ d 1) #:width 2 #:align 'right)) ,@(make-list (- 42 pfx days) " "))))))) (let ([s #"nZA7CsAgDED3nCLgoAU/3Uvv4SCE3qKD5OyNWvoBhdIHSswjMYp4YR2z80Tk8StOgP sY0EyrMZOE6WsL3u4G5lyV+d8MyVOy8hZBt7RSMca9Ac/KUIs1L/BOysb50XMtMzEj ZqiuRxIVqI+4kSpy7GqpXNsz+bfpfWIGOAA="] [o (open-output-string)]) (inflate (open-input-bytes (base64-decode s)) o) (display (regexp-replace #rx"~a" (get-output-string o) (~a yr)))) (for-each displayln (dropf-right (for*/list ([3ms (nsplit 3 months)] [s (apply map list 3ms)]) (regexp-replace #rx" +$" (string-join s " ") "")) (λ(s) (equal? "" s)))))   (calendar 1969)
http://rosettacode.org/wiki/Brownian_tree
Brownian tree
Brownian tree You are encouraged to solve this task according to the task description, using any language you may know. Task Generate and draw a   Brownian Tree. A Brownian Tree is generated as a result of an initial seed, followed by the interaction of two processes. The initial "seed" is placed somewhere within the field. Where is not particularly important; it could be randomized, or it could be a fixed point. Particles are injected into the field, and are individually given a (typically random) motion pattern. When a particle collides with the seed or tree, its position is fixed, and it's considered to be part of the tree. Because of the lax rules governing the random nature of the particle's placement and motion, no two resulting trees are really expected to be the same, or even necessarily have the same general shape.
#Wren
Wren
import "graphics" for Canvas, Color import "dome" for Window import "random" for Random   var Rand = Random.new()   var N8 = [ [-1, -1], [-1, 0], [-1, 1], [ 0, -1], [ 0, 1], [ 1, -1], [ 1, 0], [ 1, 1] ]   class BrownianTree { construct new(width, height, particles) { Window.title = "Brownian Tree" Window.resize(width, height) Canvas.resize(width, height) _w = width _h = height _n = particles }   init() { Canvas.cls(Color.brown) // off center seed position makes pleasingly asymetrical tree Canvas.pset(_w/3, _h/3, Color.white) var x = 0 var y = 0 var a = 0 while (a < _n) { // generate random position for new particle x = Rand.int(_w) y = Rand.int(_h) var outer = false var p = Canvas.pget(x, y) if (p == Color.white) { // as position is already set, find a nearby free position. while (p == Color.white) { x = x + Rand.int(3) - 1 y = y + Rand.int(3) - 1 var ok = x >= 0 && x < _w && y >= 0 && y < _h if (ok) { p = Canvas.pget(x, y) } else { // out of bounds, consider particle lost outer = true a = a + 1 break } } } else { // else particle is in free space // let it wonder until it touches tree while (!hasNeighbor(x, y)) { x = x + Rand.int(3) - 1 y = y + Rand.int(3) - 1 var ok = x >= 0 && x < _w && y >= 0 && y < _h if (ok) { p = Canvas.pget(x, y) } else { // out of bounds, consider particle lost outer = true a = a + 1 break } } } if (outer) continue // x, y now specify a free position touching the tree Canvas.pset(x, y, Color.white) a = a + 1 // progress indicator if (a % 100 == 0) System.print("%(a) of %(_n)") a = a + 1 } }   hasNeighbor(x, y) { for (n in N8) { var xn = x + n[0] var yn = y + n[1] var ok = xn >= 0 && xn < _w && yn >= 0 && yn < _h if (ok && Canvas.pget(xn, yn) == Color.white) return true } return false }   update() {}   draw(alpha) {} }   var Game = BrownianTree.new(200, 150, 7500)
http://rosettacode.org/wiki/Bulls_and_cows
Bulls and cows
Bulls and Cows Task Create a four digit random number from the digits   1   to   9,   without duplication. The program should:   ask for guesses to this number   reject guesses that are malformed   print the score for the guess The score is computed as: The player wins if the guess is the same as the randomly chosen number, and the program ends. A score of one bull is accumulated for each digit in the guess that equals the corresponding digit in the randomly chosen initial number. A score of one cow is accumulated for each digit in the guess that also appears in the randomly chosen number, but in the wrong position. Related tasks   Bulls and cows/Player   Guess the number   Guess the number/With Feedback   Mastermind
#Maple
Maple
BC := proc(n) #where n is the number of turns the user wishes to play before they quit local target, win, numGuesses, guess, bulls, cows, i, err; target := [0, 0, 0, 0]: randomize(); #This is a command that makes sure that the numbers are truly randomized each time, otherwise your first time will always give the same result. while member(0, target) or numelems({op(target)}) < 4 do #loop continues to generate random numbers until you get one with no repeating digits or 0s target := [seq(parse(i), i in convert(rand(1234..9876)(), string))]: #a list of random numbers end do:   win := false: numGuesses := 0: while win = false and numGuesses < n do #loop allows the user to play until they win or until a set amount of turns have passed err := true; while err do #loop asks for values until user enters a valid number printf("Please enter a 4 digit integer with no repeating digits\n"); try#catches any errors in user input guess := [seq(parse(i), i in readline())]; if hastype(guess, 'Not(numeric)', 'exclude_container') then printf("Postive integers only! Please guess again.\n\n"); elif numelems(guess) <> 4 then printf("4 digit numbers only! Please guess again.\n\n"); elif numelems({op(guess)}) < 4 then printf("No repeating digits! Please guess again.\n\n"); elif member(0, guess) then printf("No 0s! Please guess again.\n\n"); else err := false; end if; catch: printf("Invalid input. Please guess again.\n\n"); end try; end do: numGuesses := numGuesses + 1; printf("Guess %a: %a\n", numGuesses, guess); bulls := 0; cows := 0; for i to 4 do #loop checks for bulls and cows in the user's guess if target[i] = guess[i] then bulls := bulls + 1; elif member(target[i], guess) then cows := cows + 1; end if; end do; if bulls = 4 then win := true; printf("The number was %a.\n", target); printf(StringTools[FormatMessage]("You won with %1 %{1|guesses|guess|guesses}.", numGuesses)); else printf(StringTools[FormatMessage]("%1 %{1|Cows|Cow|Cows}, %2 %{2|Bulls|Bull|Bulls}.\n\n", cows, bulls)); end if; end do: if win = false and numGuesses >= n then printf("You lost! The number was %a.\n", target); end if; return NULL; end proc:
http://rosettacode.org/wiki/Caesar_cipher
Caesar cipher
Task Implement a Caesar cipher, both encoding and decoding. The key is an integer from 1 to 25. This cipher rotates (either towards left or right) the letters of the alphabet (A to Z). The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A). So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC". This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys. Caesar cipher is identical to Vigenère cipher with a key of length 1. Also, Rot-13 is identical to Caesar cipher with key 13. Related tasks Rot-13 Substitution Cipher Vigenère Cipher/Cryptanalysis
#Hoon
Hoon
|% ++ enc |= [msg=tape key=@ud] ^- tape (turn `(list @)`msg |=(n=@ud (add (mod (add (sub n 'A') key) 26) 'A'))) ++ dec |= [msg=tape key=@ud] (enc msg (sub 26 key)) --
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#PARI.2FGP
PARI/GP
f(); \\ zero arguments sin(Pi/2); \\ fixed number of arguments vecsort([5,6]) != vecsort([5,6],,4) \\ optional arguments Str("gg", 1, "hh") \\ variable number of arguments call(Str, ["gg", 1, "hh"]) \\ variable number of arguments in a vector (x->x^2)(3); \\ first-class x = sin(0); \\ get function value
http://rosettacode.org/wiki/Catalan_numbers
Catalan numbers
Catalan numbers You are encouraged to solve this task according to the task description, using any language you may know. Catalan numbers are a sequence of numbers which can be defined directly: C n = 1 n + 1 ( 2 n n ) = ( 2 n ) ! ( n + 1 ) ! n !  for  n ≥ 0. {\displaystyle C_{n}={\frac {1}{n+1}}{2n \choose n}={\frac {(2n)!}{(n+1)!\,n!}}\qquad {\mbox{ for }}n\geq 0.} Or recursively: C 0 = 1 and C n + 1 = ∑ i = 0 n C i C n − i for  n ≥ 0 ; {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n+1}=\sum _{i=0}^{n}C_{i}\,C_{n-i}\quad {\text{for }}n\geq 0;} Or alternatively (also recursive): C 0 = 1 and C n = 2 ( 2 n − 1 ) n + 1 C n − 1 , {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n}={\frac {2(2n-1)}{n+1}}C_{n-1},} Task Implement at least one of these algorithms and print out the first 15 Catalan numbers with each. Memoization   is not required, but may be worth the effort when using the second method above. Related tasks Catalan numbers/Pascal's triangle Evaluate binomial coefficients
#Ring
Ring
  for n = 1 to 15 see catalan(n) + nl next   func catalan n if n = 0 return 1 ok cat = 2 * (2 * n - 1) * catalan(n - 1) / (n + 1) return cat  
http://rosettacode.org/wiki/Calendar
Calendar
Create a routine that will generate a text calendar for any year. Test the calendar by generating a calendar for the year 1969, on a device of the time. Choose one of the following devices: A line printer with a width of 132 characters. An IBM 3278 model 4 terminal (80×43 display with accented characters). Target formatting the months of the year to fit nicely across the 80 character width screen. Restrict number of lines in test output to 43. (Ideally, the program will generate well-formatted calendars for any page width from 20 characters up.) Kudos (κῦδος) for routines that also transition from Julian to Gregorian calendar. This task is inspired by Real Programmers Don't Use PASCAL by Ed Post, Datamation, volume 29 number 7, July 1983. THE REAL PROGRAMMER'S NATURAL HABITAT "Taped to the wall is a line-printer Snoopy calender for the year 1969." For further Kudos see task CALENDAR, where all code is to be in UPPERCASE. For economy of size, do not actually include Snoopy generation in either the code or the output, instead just output a place-holder. Related task   Five weekends
#Raku
Raku
my $months-per-row = 3; my @weekday-names = <Mo Tu We Th Fr Sa Su>; my @month-names = <Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec>;   my Int() $year = @*ARGS.shift || 1969; say fmt-year($year);   sub fmt-year ($year) { my @month-strs; @month-strs[$_] = [fmt-month($year, $_).lines] for 1 .. 12; my @C = ' ' x 30 ~ $year, ''; for 1, 1+$months-per-row ... 12 -> $month { while @month-strs[$month] { for ^$months-per-row -> $column { @C[*-1] ~= @month-strs[$month+$column].shift ~ ' ' x 3 if @month-strs[$month+$column]; } @C.push: ''; } @C.push: ''; } @C.join: "\n"; }   sub fmt-month ($year, $month) { my $date = Date.new($year,$month,1); @month-names[$month-1].fmt("%-20s\n") ~ @weekday-names ~ "\n" ~ ((' ' xx $date.day-of-week - 1), (1..$date.days-in-month)».fmt('%2d')).flat.rotor(7, :partial).join("\n") ~ (' ' if $_ < 7) ~ (' ' xx 7-$_).join(' ') given Date.new($year, $month, $date.days-in-month).day-of-week; }
http://rosettacode.org/wiki/Brownian_tree
Brownian tree
Brownian tree You are encouraged to solve this task according to the task description, using any language you may know. Task Generate and draw a   Brownian Tree. A Brownian Tree is generated as a result of an initial seed, followed by the interaction of two processes. The initial "seed" is placed somewhere within the field. Where is not particularly important; it could be randomized, or it could be a fixed point. Particles are injected into the field, and are individually given a (typically random) motion pattern. When a particle collides with the seed or tree, its position is fixed, and it's considered to be part of the tree. Because of the lax rules governing the random nature of the particle's placement and motion, no two resulting trees are really expected to be the same, or even necessarily have the same general shape.
#XPL0
XPL0
include c:\cxpl\codes; \intrinsic 'code' declarations def W=128, H=W; \width and height of field int X, Y; [SetVid($13); \set 320x200 graphic video mode Point(W/2, H/2, 6\brown\); \place seed in center of field loop [repeat X:= Ran(W); Y:= Ran(H); \inject particle until ReadPix(X,Y) = 0; \ in an empty location loop [Point(X, Y, 6\brown\); \show particle if ReadPix(X-1,Y) or ReadPix(X+1,Y) or \particle collided ReadPix(X,Y-1) or ReadPix(X,Y+1) then quit; Point(X, Y, 0\black\); \erase particle X:= X + Ran(3)-1; \(Brownian) move particle Y:= Y + Ran(3)-1; if X<0 or X>=W or Y<0 or Y>=H then quit; \out of bounds ]; if KeyHit then [SetVid(3); quit]; \restore text mode ]; ]
http://rosettacode.org/wiki/Brownian_tree
Brownian tree
Brownian tree You are encouraged to solve this task according to the task description, using any language you may know. Task Generate and draw a   Brownian Tree. A Brownian Tree is generated as a result of an initial seed, followed by the interaction of two processes. The initial "seed" is placed somewhere within the field. Where is not particularly important; it could be randomized, or it could be a fixed point. Particles are injected into the field, and are individually given a (typically random) motion pattern. When a particle collides with the seed or tree, its position is fixed, and it's considered to be part of the tree. Because of the lax rules governing the random nature of the particle's placement and motion, no two resulting trees are really expected to be the same, or even necessarily have the same general shape.
#zkl
zkl
w:=h:=400; numParticles:=20_000; bitmap:=PPM(w+2,h+2,0); // add borders as clip regions   bitmap[w/2,h/2]=0xff|ff|ff; // plant seed bitmap.circle(w/2,h/2,h/2,0x0f|0f|0f); // plant seeds   fcn touching(x,y,bitmap){ // is (x,y) touching another pixel? // (x,y) isn't on the border/edge of bitmap so no edge conditions var [const] box=T(T(-1,-1),T(0,-1),T(1,-1), T(-1, 0), T(1, 0), T(-1, 1),T(0, 1),T(1, 1)); box.filter1('wrap([(a,b)]){ bitmap[a+x,b+y] }); //-->False: not touching, (a,b) if is }   while(numParticles){ c:=(0x1|00|00).random(0x1|00|00|00) + (0x1|00).random(0x1|00|00) + (0x1).random(0x1|00); reg x,y; do{ x=(1).random(w); y=(1).random(h); }while(bitmap[x,y]); // find empty spot while(1){ // stagger around until bump into a particle, then attach barnicle if(touching(x,y,bitmap)){ bitmap[x,y]=c; bitmap.write(f:=File("brownianTree.zkl.ppm","wb")); // tell ImageViewer to update image numParticles-=1; break; } x+=(-1).random(2); y+=(-1).random(2); // [-1,0,1] if( not ((0<x<w) and (0<y<h)) ){ // next to border --> color border bitmap[x,y]=c; break; } } } bitmap.writeJPGFile("brownianTree.zkl.jpg"); // the final image
http://rosettacode.org/wiki/Bulls_and_cows
Bulls and cows
Bulls and Cows Task Create a four digit random number from the digits   1   to   9,   without duplication. The program should:   ask for guesses to this number   reject guesses that are malformed   print the score for the guess The score is computed as: The player wins if the guess is the same as the randomly chosen number, and the program ends. A score of one bull is accumulated for each digit in the guess that equals the corresponding digit in the randomly chosen initial number. A score of one cow is accumulated for each digit in the guess that also appears in the randomly chosen number, but in the wrong position. Related tasks   Bulls and cows/Player   Guess the number   Guess the number/With Feedback   Mastermind
#Mathematica.2FWolfram_Language
Mathematica/Wolfram Language
digits=Last@FixedPointList[If[Length@Union@#==4,#,Table[Random[Integer,{1,9}],{4}]]&,{}] codes=ToCharacterCode[StringJoin[ToString/@digits]]; Module[{r,bulls,cows}, While[True, r=InputString[]; If[r===$Canceled,Break[], With[{userCodes=ToCharacterCode@r}, If[userCodes===codes,Print[r<>": You got it!"];Break[], If[Length@userCodes==Length@codes, bulls=Count[userCodes-codes,0];cows=Length@Intersection[codes,userCodes]-bulls; Print[r<>": "<>ToString[bulls]<>"bull(s), "<>ToString@cows<>"cow(s)."], Print["Guess four digits."]]]]]]]
http://rosettacode.org/wiki/Caesar_cipher
Caesar cipher
Task Implement a Caesar cipher, both encoding and decoding. The key is an integer from 1 to 25. This cipher rotates (either towards left or right) the letters of the alphabet (A to Z). The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A). So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC". This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys. Caesar cipher is identical to Vigenère cipher with a key of length 1. Also, Rot-13 is identical to Caesar cipher with key 13. Related tasks Rot-13 Substitution Cipher Vigenère Cipher/Cryptanalysis
#Icon_and_Unicon
Icon and Unicon
procedure main() ctext := caesar(ptext := map("The quick brown fox jumped over the lazy dog")) dtext := caesar(ctext,,"decrypt") write("Plain text = ",image(ptext)) write("Encphered text = ",image(ctext)) write("Decphered text = ",image(dtext)) end   procedure caesar(text,k,mode) #: mono-alphabetic shift cipher /k := 3 k := (((k % *&lcase) + *&lcase) % *&lcase) + 1 case mode of { &null|"e"|"encrypt": return map(text,&lcase,(&lcase||&lcase)[k+:*&lcase]) "d"|"decrypt" : return map(text,(&lcase||&lcase)[k+:*&lcase],&lcase) } end
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#Pascal
Pascal
foo
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#Perl
Perl
foo(); # Call foo on the null list &foo(); # Ditto foo($arg1, $arg2); # Call foo on $arg1 and $arg2 &foo($arg1, $arg2); # Ditto; ignores prototypes
http://rosettacode.org/wiki/Catalan_numbers
Catalan numbers
Catalan numbers You are encouraged to solve this task according to the task description, using any language you may know. Catalan numbers are a sequence of numbers which can be defined directly: C n = 1 n + 1 ( 2 n n ) = ( 2 n ) ! ( n + 1 ) ! n !  for  n ≥ 0. {\displaystyle C_{n}={\frac {1}{n+1}}{2n \choose n}={\frac {(2n)!}{(n+1)!\,n!}}\qquad {\mbox{ for }}n\geq 0.} Or recursively: C 0 = 1 and C n + 1 = ∑ i = 0 n C i C n − i for  n ≥ 0 ; {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n+1}=\sum _{i=0}^{n}C_{i}\,C_{n-i}\quad {\text{for }}n\geq 0;} Or alternatively (also recursive): C 0 = 1 and C n = 2 ( 2 n − 1 ) n + 1 C n − 1 , {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n}={\frac {2(2n-1)}{n+1}}C_{n-1},} Task Implement at least one of these algorithms and print out the first 15 Catalan numbers with each. Memoization   is not required, but may be worth the effort when using the second method above. Related tasks Catalan numbers/Pascal's triangle Evaluate binomial coefficients
#Ruby
Ruby
def factorial(n) (1..n).reduce(1, :*) end   # direct   def catalan_direct(n) factorial(2*n) / (factorial(n+1) * factorial(n)) end   # recursive   def catalan_rec1(n) return 1 if n == 0 (0...n).inject(0) {|sum, i| sum + catalan_rec1(i) * catalan_rec1(n-1-i)} end   def catalan_rec2(n) return 1 if n == 0 2*(2*n - 1) * catalan_rec2(n-1) / (n+1) end   # performance and results   require 'benchmark' require 'memoize' include Memoize   Benchmark.bm(17) do |b| b.report('catalan_direct') {16.times {|n| catalan_direct(n)} } b.report('catalan_rec1') {16.times {|n| catalan_rec1(n)} } b.report('catalan_rec2') {16.times {|n| catalan_rec2(n)} }   memoize :catalan_rec1 b.report('catalan_rec1(memo)'){16.times {|n| catalan_rec1(n)} } end   puts "\n direct rec1 rec2" 16.times {|n| puts "%2d :%9d%9d%9d" % [n, catalan_direct(n), catalan_rec1(n), catalan_rec2(n)]}
http://rosettacode.org/wiki/Calendar
Calendar
Create a routine that will generate a text calendar for any year. Test the calendar by generating a calendar for the year 1969, on a device of the time. Choose one of the following devices: A line printer with a width of 132 characters. An IBM 3278 model 4 terminal (80×43 display with accented characters). Target formatting the months of the year to fit nicely across the 80 character width screen. Restrict number of lines in test output to 43. (Ideally, the program will generate well-formatted calendars for any page width from 20 characters up.) Kudos (κῦδος) for routines that also transition from Julian to Gregorian calendar. This task is inspired by Real Programmers Don't Use PASCAL by Ed Post, Datamation, volume 29 number 7, July 1983. THE REAL PROGRAMMER'S NATURAL HABITAT "Taped to the wall is a line-printer Snoopy calender for the year 1969." For further Kudos see task CALENDAR, where all code is to be in UPPERCASE. For economy of size, do not actually include Snoopy generation in either the code or the output, instead just output a place-holder. Related task   Five weekends
#Rebol
Rebol
  do [if "" = y: ask "Year (ENTER for current):^/^/" [prin y: now/year] foreach m system/locale/months [ prin rejoin ["^/^/ " m "^/^/ "] foreach day system/locale/days [prin join copy/part day 2 " "] print "" f: to-date rejoin ["1-"m"-"y] loop f/weekday - 1 [prin " "] repeat i 31 [ if attempt [c: to-date rejoin [i"-"m"-"y]][ prin join either 1 = length? form i [" "][" "] i if c/weekday = 7 [print ""] ] ] ] ask "^/^/Press [ENTER] to Continue..."]  
http://rosettacode.org/wiki/Brownian_tree
Brownian tree
Brownian tree You are encouraged to solve this task according to the task description, using any language you may know. Task Generate and draw a   Brownian Tree. A Brownian Tree is generated as a result of an initial seed, followed by the interaction of two processes. The initial "seed" is placed somewhere within the field. Where is not particularly important; it could be randomized, or it could be a fixed point. Particles are injected into the field, and are individually given a (typically random) motion pattern. When a particle collides with the seed or tree, its position is fixed, and it's considered to be part of the tree. Because of the lax rules governing the random nature of the particle's placement and motion, no two resulting trees are really expected to be the same, or even necessarily have the same general shape.
#ZX_Spectrum_Basic
ZX Spectrum Basic
10 LET np=1000 20 PAPER 0: INK 4: CLS 30 PLOT 128,88 40 FOR i=1 TO np 50 GO SUB 1000 60 IF NOT ((POINT (x+1,y+1)+POINT (x,y+1)+POINT (x+1,y)+POINT (x-1,y-1)+POINT (x-1,y)+POINT (x,y-1))=0) THEN GO TO 100 70 LET x=x+RND*2-1: LET y=y+RND*2-1 80 IF x<1 OR x>254 OR y<1 OR y>174 THEN GO SUB 1000 90 GO TO 60 100 PLOT x,y 110 NEXT i 120 STOP 1000 REM Calculate new pos 1010 LET x=RND*254 1020 LET y=RND*174 1030 RETURN  
http://rosettacode.org/wiki/Bulls_and_cows
Bulls and cows
Bulls and Cows Task Create a four digit random number from the digits   1   to   9,   without duplication. The program should:   ask for guesses to this number   reject guesses that are malformed   print the score for the guess The score is computed as: The player wins if the guess is the same as the randomly chosen number, and the program ends. A score of one bull is accumulated for each digit in the guess that equals the corresponding digit in the randomly chosen initial number. A score of one cow is accumulated for each digit in the guess that also appears in the randomly chosen number, but in the wrong position. Related tasks   Bulls and cows/Player   Guess the number   Guess the number/With Feedback   Mastermind
#MATLAB
MATLAB
function BullsAndCows % Plays the game Bulls and Cows as the "game master"   % Create a secret number nDigits = 4; lowVal = 1; highVal = 9; digitList = lowVal:highVal; secret = zeros(1, 4); for k = 1:nDigits idx = randi(length(digitList)); secret(k) = digitList(idx); digitList(idx) = []; end   % Give game information fprintf('Welcome to Bulls and Cows!\n') fprintf('Try to guess the %d-digit number (no repeated digits).\n', nDigits) fprintf('Digits are between %d and %d (inclusive).\n', lowVal, highVal) fprintf('Score: 1 Bull per correct digit in correct place.\n') fprintf(' 1 Cow per correct digit in incorrect place.\n') fprintf('The number has been chosen. Now it''s your moooooove!\n') gs = input('Guess: ', 's');   % Loop until user guesses right or quits (no guess) nGuesses = 1; while gs gn = str2double(gs); if isnan(gn) || length(gn) > 1 % Not a scalar fprintf('Malformed guess. Keep to valid scalars.\n') gs = input('Try again: ', 's'); else g = sprintf('%d', gn) - '0'; if length(g) ~= nDigits || any(g < lowVal) || any(g > highVal) || ... length(unique(g)) ~= nDigits % Invalid number for game fprintf('Malformed guess. Remember:\n') fprintf('  %d digits\n', nDigits) fprintf(' Between %d and %d inclusive\n', lowVal, highVal) fprintf(' No repeated digits\n') gs = input('Try again: ', 's'); else score = CountBullsCows(g, secret); if score(1) == nDigits fprintf('You win! Bully for you! Only %d guesses.\n', nGuesses) gs = ''; else fprintf('Score: %d Bulls, %d Cows\n', score) gs = input('Guess: ', 's'); end end end nGuesses = nGuesses+1; % Counts malformed guesses end end   function score = CountBullsCows(guess, correct) % Checks the guessed array of digits against the correct array to find the score % Assumes arrays of same length and valid numbers bulls = guess == correct; cows = ismember(guess(~bulls), correct); score = [sum(bulls) sum(cows)]; end
http://rosettacode.org/wiki/Caesar_cipher
Caesar cipher
Task Implement a Caesar cipher, both encoding and decoding. The key is an integer from 1 to 25. This cipher rotates (either towards left or right) the letters of the alphabet (A to Z). The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A). So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC". This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys. Caesar cipher is identical to Vigenère cipher with a key of length 1. Also, Rot-13 is identical to Caesar cipher with key 13. Related tasks Rot-13 Substitution Cipher Vigenère Cipher/Cryptanalysis
#IS-BASIC
IS-BASIC
100 PROGRAM "CaesarCi.bas" 110 STRING M$*254 120 INPUT PROMPT "String: ":M$ 130 DO 140 INPUT PROMPT "Key (1-25): ":KEY 150 LOOP UNTIL KEY>0 AND KEY<26 160 PRINT "Original message: ";M$ 170 CALL ENCRYPT(M$,KEY) 180 PRINT "Encrypted message: ";M$ 190 CALL DECRYPT(M$,KEY) 200 PRINT "Decrypted message: ";M$ 210 DEF ENCRYPT(REF M$,KEY) 220 STRING T$*254 230 LET T$="" 240 FOR I=1 TO LEN(M$) 250 SELECT CASE M$(I) 260 CASE "A" TO "Z" 270 LET T$=T$&CHR$(65+MOD(ORD(M$(I))-65+KEY,26)) 280 CASE "a" TO "z" 290 LET T$=T$&CHR$(97+MOD(ORD(M$(I))-97+KEY,26)) 300 CASE ELSE 310 LET T$=T$&M$(I) 320 END SELECT 330 NEXT 340 LET M$=T$ 350 END DEF 360 DEF DECRYPT(REF M$,KEY) 370 STRING T$*254 380 LET T$="" 390 FOR I=1 TO LEN(M$) 400 SELECT CASE M$(I) 410 CASE "A" TO "Z" 420 LET T$=T$&CHR$(65+MOD(ORD(M$(I))-39-KEY,26)) 430 CASE "a" TO "z" 440 LET T$=T$&CHR$(97+MOD(ORD(M$(I))-71-KEY,26)) 450 CASE ELSE 460 LET T$=T$&M$(I) 470 END SELECT 480 NEXT 490 LET M$=T$ 500 END DEF
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#Phix
Phix
{} = myfunction()
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#Phixmonti
Phixmonti
def saludo "Hola mundo" print nl enddef   saludo   getid saludo exec
http://rosettacode.org/wiki/Catalan_numbers
Catalan numbers
Catalan numbers You are encouraged to solve this task according to the task description, using any language you may know. Catalan numbers are a sequence of numbers which can be defined directly: C n = 1 n + 1 ( 2 n n ) = ( 2 n ) ! ( n + 1 ) ! n !  for  n ≥ 0. {\displaystyle C_{n}={\frac {1}{n+1}}{2n \choose n}={\frac {(2n)!}{(n+1)!\,n!}}\qquad {\mbox{ for }}n\geq 0.} Or recursively: C 0 = 1 and C n + 1 = ∑ i = 0 n C i C n − i for  n ≥ 0 ; {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n+1}=\sum _{i=0}^{n}C_{i}\,C_{n-i}\quad {\text{for }}n\geq 0;} Or alternatively (also recursive): C 0 = 1 and C n = 2 ( 2 n − 1 ) n + 1 C n − 1 , {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n}={\frac {2(2n-1)}{n+1}}C_{n-1},} Task Implement at least one of these algorithms and print out the first 15 Catalan numbers with each. Memoization   is not required, but may be worth the effort when using the second method above. Related tasks Catalan numbers/Pascal's triangle Evaluate binomial coefficients
#Run_BASIC
Run BASIC
FOR i = 1 TO 15 PRINT i;" ";catalan(i) NEXT   FUNCTION catalan(n) catalan = 1 if n <> 0 then catalan = ((2 * ((2 * n) - 1)) / (n + 1)) * catalan(n - 1) END FUNCTION
http://rosettacode.org/wiki/Calendar
Calendar
Create a routine that will generate a text calendar for any year. Test the calendar by generating a calendar for the year 1969, on a device of the time. Choose one of the following devices: A line printer with a width of 132 characters. An IBM 3278 model 4 terminal (80×43 display with accented characters). Target formatting the months of the year to fit nicely across the 80 character width screen. Restrict number of lines in test output to 43. (Ideally, the program will generate well-formatted calendars for any page width from 20 characters up.) Kudos (κῦδος) for routines that also transition from Julian to Gregorian calendar. This task is inspired by Real Programmers Don't Use PASCAL by Ed Post, Datamation, volume 29 number 7, July 1983. THE REAL PROGRAMMER'S NATURAL HABITAT "Taped to the wall is a line-printer Snoopy calender for the year 1969." For further Kudos see task CALENDAR, where all code is to be in UPPERCASE. For economy of size, do not actually include Snoopy generation in either the code or the output, instead just output a place-holder. Related task   Five weekends
#REXX
REXX
11 9999999 6666666 9999999 111 999999999 666666666 999999999 1111 99 99 66 66 99 99 11 99 99 66 99 99 11 99 999 66 99 999 11 999999999 66 666666 999999999 11 99999 99 6666666666 99999 99 11 99 666 66 99 11 99 66 66 99 11 99 99 66 66 99 99 111111 99999999 66666666 99999999 111111 999999 666666 999999
http://rosettacode.org/wiki/Bulls_and_cows
Bulls and cows
Bulls and Cows Task Create a four digit random number from the digits   1   to   9,   without duplication. The program should:   ask for guesses to this number   reject guesses that are malformed   print the score for the guess The score is computed as: The player wins if the guess is the same as the randomly chosen number, and the program ends. A score of one bull is accumulated for each digit in the guess that equals the corresponding digit in the randomly chosen initial number. A score of one cow is accumulated for each digit in the guess that also appears in the randomly chosen number, but in the wrong position. Related tasks   Bulls and cows/Player   Guess the number   Guess the number/With Feedback   Mastermind
#MAXScript
MAXScript
  numCount = 4 -- number of digits to use   digits = #(1, 2, 3, 4, 5, 6, 7, 8, 9) num = "" while num.count < numCount and digits.count > 0 do ( local r = random 1 digits.count append num (digits[r] as string) deleteitem digits r ) digits = undefined numGuesses = 0 inf = "Rules: \n1. Choose only % unique digits in any combination"+\ " (0 can't be used).\n2. Only positive integers are allowed."+\ "\n3. For each digit that is in it's place, you get a bull,\n"+\ "\tand for each digit that is not in it's place, you get a cow."+\ "\n4. The game is won when your number matches the number I chose."+\ "\n\nPress [esc] to quit the game.\n\n" clearlistener() format inf num.count while not keyboard.escpressed do ( local userVal = getkbvalue prompt:"\nEnter your number: " if (userVal as string) == num do ( format "\nCorrect! The number is %. It took you % moves.\n" num numGuesses exit with OK ) local bulls = 0 local cows = 0 local badInput = false case of ( (classof userVal != integer): ( format "\nThe number must be a positive integer.\n" badInput = true ) ((userVal as string).count != num.count): ( format "\nThe number must have % digits.\n" num.count badInput = true ) ((makeuniquearray (for i in 1 to (userVal as string).count \ collect (userVal as string)[i])).count != (userVal as string).count): ( format "\nThe number can only have unique digits.\n" badInput = true ) ) if not badInput do ( userVal = userVal as string i = 1 while i <= userVal.count do ( for j = 1 to num.count do ( if userVal[i] == num[j] do ( if i == j then bulls += 1 else cows += 1 ) ) i += 1 ) numGuesses += 1 format "\nBulls: % Cows: %\n" bulls cows ) )
http://rosettacode.org/wiki/Caesar_cipher
Caesar cipher
Task Implement a Caesar cipher, both encoding and decoding. The key is an integer from 1 to 25. This cipher rotates (either towards left or right) the letters of the alphabet (A to Z). The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A). So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC". This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys. Caesar cipher is identical to Vigenère cipher with a key of length 1. Also, Rot-13 is identical to Caesar cipher with key 13. Related tasks Rot-13 Substitution Cipher Vigenère Cipher/Cryptanalysis
#J
J
cndx=: [: , 65 97 +/ 26 | (i.26)&+ caesar=: (cndx 0)}&a.@u:@cndx@[ {~ a.i.]
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#PicoLisp
PicoLisp
(foo) (bar 1 'arg 2 'mumble)
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#PureBasic
PureBasic
Procedure Saludo() PrintN("Hola mundo!") EndProcedure   Procedure.s Copialo(txt.s, siNo.b, final.s = "") Define nuevaCadena.s, resul.s   For cont.b = 1 To siNo nuevaCadena + txt Next   Resul = Trim(nuevaCadena) + final   ProcedureReturn resul EndProcedure   Procedure testNumeros(a.i, b.i, c.i = 0) PrintN(Str(a) + #TAB$ + Str(b) + #TAB$ + Str(c)) EndProcedure   Procedure testCadenas(txt.s) For cont.b = 1 To Len(txt) Print(Mid(txt,cont,1)) Next cont EndProcedure   OpenConsole() Saludo() PrintN(Copialo("Saludos ", 6)) PrintN(Copialo("Saludos ", 3, "!!")) PrintN("") testNumeros(1, 2, 3) testNumeros(1, 2) PrintN("") testCadenas("1, 2, 3, 4, cadena, 6, 7, 8, \'incluye texto\'")   Input() CloseConsole()
http://rosettacode.org/wiki/Catalan_numbers
Catalan numbers
Catalan numbers You are encouraged to solve this task according to the task description, using any language you may know. Catalan numbers are a sequence of numbers which can be defined directly: C n = 1 n + 1 ( 2 n n ) = ( 2 n ) ! ( n + 1 ) ! n !  for  n ≥ 0. {\displaystyle C_{n}={\frac {1}{n+1}}{2n \choose n}={\frac {(2n)!}{(n+1)!\,n!}}\qquad {\mbox{ for }}n\geq 0.} Or recursively: C 0 = 1 and C n + 1 = ∑ i = 0 n C i C n − i for  n ≥ 0 ; {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n+1}=\sum _{i=0}^{n}C_{i}\,C_{n-i}\quad {\text{for }}n\geq 0;} Or alternatively (also recursive): C 0 = 1 and C n = 2 ( 2 n − 1 ) n + 1 C n − 1 , {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n}={\frac {2(2n-1)}{n+1}}C_{n-1},} Task Implement at least one of these algorithms and print out the first 15 Catalan numbers with each. Memoization   is not required, but may be worth the effort when using the second method above. Related tasks Catalan numbers/Pascal's triangle Evaluate binomial coefficients
#Rust
Rust
fn c_n(n: u64) -> u64 { match n { 0 => 1, _ => c_n(n - 1) * 2 * (2 * n - 1) / (n + 1) } }   fn main() { for i in 1..16 { println!("c_n({}) = {}", i, c_n(i)); } }
http://rosettacode.org/wiki/Calendar
Calendar
Create a routine that will generate a text calendar for any year. Test the calendar by generating a calendar for the year 1969, on a device of the time. Choose one of the following devices: A line printer with a width of 132 characters. An IBM 3278 model 4 terminal (80×43 display with accented characters). Target formatting the months of the year to fit nicely across the 80 character width screen. Restrict number of lines in test output to 43. (Ideally, the program will generate well-formatted calendars for any page width from 20 characters up.) Kudos (κῦδος) for routines that also transition from Julian to Gregorian calendar. This task is inspired by Real Programmers Don't Use PASCAL by Ed Post, Datamation, volume 29 number 7, July 1983. THE REAL PROGRAMMER'S NATURAL HABITAT "Taped to the wall is a line-printer Snoopy calender for the year 1969." For further Kudos see task CALENDAR, where all code is to be in UPPERCASE. For economy of size, do not actually include Snoopy generation in either the code or the output, instead just output a place-holder. Related task   Five weekends
#Ring
Ring
  # Project : Calendar   load "guilib.ring" load "stdlib.ring"   new qapp { win1 = new qwidget() {   day = list(12) pos = newlist(12,37) month = list(12) week = list(7) weekday = list(7) button = newlist(7,6) monthsnames = list(12) week = ["Su", "Mo", "Tu", "We", "Th", "Fr", "Sa"] months = ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"] daysnew = [[5,1], [6,2], [7,3], [1,4], [2,5], [3,6], [4,7]] mo = [4,0,0,3,5,1,3,6,2,4,0,2] mon = [31,28,31,30,31,30,31,31,30,31,30,31] m2 = (((1969-1900)%7) + floor((1969 - 1900)/4) % 7) % 7 for n = 1 to 12 month[n] = (mo[n] + m2) % 7 x = (month[n] + 1) % 7 + 1 for m = 1 to len(daysnew) if daysnew[m][1] = x nr = m ok next day[n] = daysnew[nr][2] next for m = 1 to 12 for n = 1 to day[m] - 1 pos[m][n] = " " next next for m = 1 to 12 for n = day[m] to 37 if n < (mon[m] + day[m]) pos[m][n] = n - day[m] + 1 else pos[m][n] = " " ok next next setwindowtitle("Calendar") setgeometry(100,100,650,800) label1 = new qlabel(win1) { setgeometry(10,10,800,600) settext("") } year = new qpushbutton(win1) { setgeometry(280,20,60,20) year.settext("1969") } for n = 1 to 4 nr = (n-1)*3+1 showmonths(nr) next for n = 1 to 12 showweeks(n) next for n = 1 to 12 showdays(n) next show() } exec() }   func showmonths(m) for n = m to m + 2 monthsnames[n] = new qpushbutton(win1) { if n%3 = 1 col = 120 rownr = floor(n/3) if rownr = 0 rownr = n/3 ok if n = 1 row = 40 else row = 40+rownr*180 ok else colnr = n%3 if colnr = 0 colnr = 3 ok rownr = floor(n/3) if n%3 = 0 rownr = floor(n/3)-1 ok col = 120 + (colnr-1)*160 row = 40 + rownr*180 ok setgeometry(col,row,60,20) monthsnames[n].settext(months[n]) } next   func showweeks(n) for m = 1 to 7 col = m%7 if col = 0 col = 7 ok weekday[m] = new qpushbutton(win1) { colnr = n % 3 if colnr = 0 colnr = 3 ok rownr = floor(n/3) if n%3 = 0 rownr = floor(n/3)-1 ok colbegin = 60 + (colnr-1)*160 rowbegin = 60 + (rownr)*180 setgeometry(colbegin+col*20,rowbegin,20,20) weekday[m].settext(week[m]) } next   func showdays(ind) rownr = floor(ind/3) if ind%3 = 0 rownr = floor(ind/3)-1 ok rowbegin = 60+rownr*180 for m = 1 to 6 for n = 1 to 7 col = n%7 if col = 0 col = 7 ok row = m button[n][m] = new qpushbutton(win1) { if ind%3 = 1 colbegin = 60 elseif ind%3 = 2 colbegin = 220 else colbegin = 380 ok setgeometry(colbegin+col*20,rowbegin+row*20,20,20) nr = (m-1)*7+n if nr <= 37 if pos[ind][nr] != " " button[n][m].settext(string(pos[ind][nr])) ok ok } next next  
http://rosettacode.org/wiki/Bulls_and_cows
Bulls and cows
Bulls and Cows Task Create a four digit random number from the digits   1   to   9,   without duplication. The program should:   ask for guesses to this number   reject guesses that are malformed   print the score for the guess The score is computed as: The player wins if the guess is the same as the randomly chosen number, and the program ends. A score of one bull is accumulated for each digit in the guess that equals the corresponding digit in the randomly chosen initial number. A score of one cow is accumulated for each digit in the guess that also appears in the randomly chosen number, but in the wrong position. Related tasks   Bulls and cows/Player   Guess the number   Guess the number/With Feedback   Mastermind
#MiniScript
MiniScript
secret = range(1,9) secret.shuffle secret = secret[:4].join("")   while true guess = input("Your guess? ").split("") if guess.len != 4 then print "Please enter 4 numbers, with no spaces." continue end if bulls = 0 cows = 0 for i in guess.indexes if secret[i] == guess[i] then bulls = bulls + 1 else if secret.indexOf(guess[i]) != null then cows = cows + 1 end if end for if bulls == 4 then print "You got it! Great job!" break end if print "You score " + bulls + " bull" + "s"*(bulls!=1) + " and " + cows + " cow" + "s"*(cows!=1) + "." end while
http://rosettacode.org/wiki/Caesar_cipher
Caesar cipher
Task Implement a Caesar cipher, both encoding and decoding. The key is an integer from 1 to 25. This cipher rotates (either towards left or right) the letters of the alphabet (A to Z). The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A). So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC". This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys. Caesar cipher is identical to Vigenère cipher with a key of length 1. Also, Rot-13 is identical to Caesar cipher with key 13. Related tasks Rot-13 Substitution Cipher Vigenère Cipher/Cryptanalysis
#Janet
Janet
  (def alphabet "abcdefghijklmnopqrstuvwxyz")   (defn rotate "shift bytes given x" [str x] (let [r (% x (length alphabet)) b (string/bytes str) abyte (get (string/bytes "a") 0) zbyte (get (string/bytes "z") 0)] (var result @[]) (for i 0 (length b) (let [ch (bor (get b i) 0x20)] # convert uppercase to lowercase (when (and (<= abyte ch) (<= ch zbyte)) (array/push result (get alphabet (% (+ (+ (+ (- zbyte abyte) 1) (- ch abyte)) r) (length alphabet))))))) (string/from-bytes ;result)))   (defn code "encodes and decodes str given argument type" [str rot type] (case type  :encode (rotate str rot)  :decode (rotate str (* rot -1))))   (defn main [& args] (let [cipher (code "The quick brown fox jumps over the lazy dog" 23 :encode) str (code cipher 23 :decode)] (print cipher) (print str)))  
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#Python
Python
def no_args(): pass # call no_args()   def fixed_args(x, y): print('x=%r, y=%r' % (x, y)) # call fixed_args(1, 2) # x=1, y=2   ## Can also called them using the parameter names, in either order: fixed_args(y=2, x=1)   ## Can also "apply" fixed_args() to a sequence: myargs=(1,2) # tuple fixed_args(*myargs)   def opt_args(x=1): print(x) # calls opt_args() # 1 opt_args(3.141) # 3.141   def var_args(*v): print(v) # calls var_args(1, 2, 3) # (1, 2, 3) var_args(1, (2,3)) # (1, (2, 3)) var_args() # ()   ## Named arguments fixed_args(y=2, x=1) # x=1, y=2   ## As a statement if 1: no_args()   ## First-class within an expression assert no_args() is None   def return_something(): return 1 x = return_something()   def is_builtin(x): print(x.__name__ in dir(__builtins__)) # calls is_builtin(pow) # True is_builtin(is_builtin) # False   # Very liberal function definition   def takes_anything(*args, **kwargs): for each in args: print(each) for key, value in sorted(kwargs.items()): print("%s:%s" % (key, value)) # Passing those to another, wrapped, function: wrapped_fn(*args, **kwargs) # (Function being wrapped can have any parameter list # ... that doesn't have to match this prototype)   ## A subroutine is merely a function that has no explicit ## return statement and will return None.   ## Python uses "Call by Object Reference". ## See, for example, http://www.python-course.eu/passing_arguments.php   ## For partial function application see: ## http://rosettacode.org/wiki/Partial_function_application#Python
http://rosettacode.org/wiki/Catalan_numbers
Catalan numbers
Catalan numbers You are encouraged to solve this task according to the task description, using any language you may know. Catalan numbers are a sequence of numbers which can be defined directly: C n = 1 n + 1 ( 2 n n ) = ( 2 n ) ! ( n + 1 ) ! n !  for  n ≥ 0. {\displaystyle C_{n}={\frac {1}{n+1}}{2n \choose n}={\frac {(2n)!}{(n+1)!\,n!}}\qquad {\mbox{ for }}n\geq 0.} Or recursively: C 0 = 1 and C n + 1 = ∑ i = 0 n C i C n − i for  n ≥ 0 ; {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n+1}=\sum _{i=0}^{n}C_{i}\,C_{n-i}\quad {\text{for }}n\geq 0;} Or alternatively (also recursive): C 0 = 1 and C n = 2 ( 2 n − 1 ) n + 1 C n − 1 , {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n}={\frac {2(2n-1)}{n+1}}C_{n-1},} Task Implement at least one of these algorithms and print out the first 15 Catalan numbers with each. Memoization   is not required, but may be worth the effort when using the second method above. Related tasks Catalan numbers/Pascal's triangle Evaluate binomial coefficients
#Scala
Scala
  object CatalanNumbers { def main(args: Array[String]): Unit = { for (n <- 0 to 15) { println("catalan(" + n + ") = " + catalan(n)) } }   def catalan(n: BigInt): BigInt = factorial(2 * n) / (factorial(n + 1) * factorial(n))   def factorial(n: BigInt): BigInt = BigInt(1).to(n).foldLeft(BigInt(1))(_ * _) }  
http://rosettacode.org/wiki/Calendar
Calendar
Create a routine that will generate a text calendar for any year. Test the calendar by generating a calendar for the year 1969, on a device of the time. Choose one of the following devices: A line printer with a width of 132 characters. An IBM 3278 model 4 terminal (80×43 display with accented characters). Target formatting the months of the year to fit nicely across the 80 character width screen. Restrict number of lines in test output to 43. (Ideally, the program will generate well-formatted calendars for any page width from 20 characters up.) Kudos (κῦδος) for routines that also transition from Julian to Gregorian calendar. This task is inspired by Real Programmers Don't Use PASCAL by Ed Post, Datamation, volume 29 number 7, July 1983. THE REAL PROGRAMMER'S NATURAL HABITAT "Taped to the wall is a line-printer Snoopy calender for the year 1969." For further Kudos see task CALENDAR, where all code is to be in UPPERCASE. For economy of size, do not actually include Snoopy generation in either the code or the output, instead just output a place-holder. Related task   Five weekends
#Ruby
Ruby
require 'date'   # Creates a calendar of _year_. Returns this calendar as a multi-line # string fit to _columns_. def cal(year, columns)   # Start at January 1. # # Date::ENGLAND marks the switch from Julian calendar to Gregorian # calendar at 1752 September 14. This removes September 3 to 13 from # year 1752. (By fortune, it keeps January 1.) # date = Date.new(year, 1, 1, Date::ENGLAND)   # Collect calendars of all 12 months. months = (1..12).collect do |month| rows = [Date::MONTHNAMES[month].center(20), "Su Mo Tu We Th Fr Sa"]   # Make array of 42 days, starting with Sunday. days = [] date.wday.times { days.push " " } while date.month == month days.push("%2d" % date.mday) date += 1 end (42 - days.length).times { days.push " " }   days.each_slice(7) { |week| rows.push(week.join " ") } next rows end   # Calculate months per row (mpr). # 1. Divide columns by 22 columns per month, rounded down. (Pretend # to have 2 extra columns; last month uses only 20 columns.) # 2. Decrease mpr if 12 months would fit in the same months per # column (mpc). For example, if we can fit 5 mpr and 3 mpc, then # we use 4 mpr and 3 mpc. mpr = (columns + 2).div 22 mpr = 12.div((12 + mpr - 1).div mpr)   # Use 20 columns per month + 2 spaces between months. width = mpr * 22 - 2   # Join months into calendar. rows = ["[Snoopy]".center(width), "#{year}".center(width)] months.each_slice(mpr) do |slice| slice[0].each_index do |i| rows.push(slice.map {|a| a[i]}.join " ") end end return rows.join("\n") end     ARGV.length == 1 or abort "usage: #{$0} year"   # Guess width of terminal. # 1. Obey environment variable COLUMNS. # 2. Try to require 'io/console' from Ruby 1.9.3. # 3. Try to run `tput co`. # 4. Assume 80 columns. columns = begin Integer(ENV["COLUMNS"] || "") rescue begin require 'io/console'; IO.console.winsize[1] rescue LoadError begin Integer(`tput cols`) rescue 80; end; end; end   puts cal(Integer(ARGV[0]), columns)
http://rosettacode.org/wiki/Bulls_and_cows
Bulls and cows
Bulls and Cows Task Create a four digit random number from the digits   1   to   9,   without duplication. The program should:   ask for guesses to this number   reject guesses that are malformed   print the score for the guess The score is computed as: The player wins if the guess is the same as the randomly chosen number, and the program ends. A score of one bull is accumulated for each digit in the guess that equals the corresponding digit in the randomly chosen initial number. A score of one cow is accumulated for each digit in the guess that also appears in the randomly chosen number, but in the wrong position. Related tasks   Bulls and cows/Player   Guess the number   Guess the number/With Feedback   Mastermind
#MUMPS
MUMPS
BullCow New bull,cow,guess,guessed,ii,number,pos,x Set number="",x=1234567890 For ii=1:1:4 Do . Set pos=$Random($Length(x))+1 . Set number=number_$Extract(x,pos) . Set $Extract(x,pos)="" . Quit Write !,"The computer has selected a number that consists" Write !,"of four different digits." Write !!,"As you are guessing the number, ""bulls"" and ""cows""" Write !,"will be awarded: a ""bull"" for each digit that is" Write !,"placed in the correct position, and a ""cow"" for each" Write !,"digit that occurs in the number, but in a different place.",! Write !,"For a guess, enter 4 digits." Write !,"Any other input is interpreted as ""I give up"".",! Set guessed=0 For Do Quit:guessed . Write !,"Your guess: " Read guess If guess'?4n Set guessed=-1 Quit . Set (bull,cow)=0,x=guess . For ii=4:-1:1 If $Extract(x,ii)=$Extract(number,ii) Do . . Set bull=bull+1,$Extract(x,ii)="" . . Quit . For ii=1:1:$Length(x) Set:number[$Extract(x,ii) cow=cow+1 . Write !,"You guessed ",guess,". That earns you " . If 'bull,'cow Write "neither bulls nor cows..." Quit . If bull Write bull," bull" Write:bull>1 "s" . If cow Write:bull " and " Write cow," cow" Write:cow>1 "s" . Write "." . If bull=4 Set guessed=1 Write !,"That's a perfect score." . Quit If guessed<0 Write !!,"The number was ",number,".",! Quit Do BullCow   The computer has selected a number that consists of four different digits.   As you are guessing the number, "bulls" and "cows" will be awarded: a "bull" for each digit that is placed in the correct position, and a "cow" for each digit that occurs in the number, but in a different place.   For a guess, enter 4 digits. Any other input is interpreted as "I give up".   Your guess: 1234 You guessed 1234. That earns you 1 cow. Your guess: 5678 You guessed 5678. That earns you 1 cow. Your guess: 9815 You guessed 9815. That earns you 1 cow. Your guess: 9824 You guessed 9824. That earns you 2 cows. Your guess: 9037 You guessed 9037. That earns you 1 bull and 2 cows. Your guess: 9048 You guessed 2789. That earns you 1 bull and 2 cows. Your guess: 2079 You guessed 2079. That earns you 1 bull and 3 cows. Your guess: 2709 You guessed 2709. That earns you 2 bulls and 2 cows. Your guess: 0729 You guessed 0729. That earns you 4 cows. Your guess: 2907 You guessed 2907. That earns you 4 bulls. That's a perfect score.
http://rosettacode.org/wiki/Caesar_cipher
Caesar cipher
Task Implement a Caesar cipher, both encoding and decoding. The key is an integer from 1 to 25. This cipher rotates (either towards left or right) the letters of the alphabet (A to Z). The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A). So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC". This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys. Caesar cipher is identical to Vigenère cipher with a key of length 1. Also, Rot-13 is identical to Caesar cipher with key 13. Related tasks Rot-13 Substitution Cipher Vigenère Cipher/Cryptanalysis
#Java
Java
public class Cipher { public static void main(String[] args) {   String str = "The quick brown fox Jumped over the lazy Dog";   System.out.println( Cipher.encode( str, 12 )); System.out.println( Cipher.decode( Cipher.encode( str, 12), 12 )); }   public static String decode(String enc, int offset) { return encode(enc, 26-offset); }   public static String encode(String enc, int offset) { offset = offset % 26 + 26; StringBuilder encoded = new StringBuilder(); for (char i : enc.toCharArray()) { if (Character.isLetter(i)) { if (Character.isUpperCase(i)) { encoded.append((char) ('A' + (i - 'A' + offset) % 26 )); } else { encoded.append((char) ('a' + (i - 'a' + offset) % 26 )); } } else { encoded.append(i); } } return encoded.toString(); } }
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#QBasic
QBasic
FUNCTION Copialo$ (txt$, siNo, final$) DIM nuevaCadena$   FOR cont = 1 TO siNo nuevaCadena$ = nuevaCadena$ + txt$ NEXT cont   Copialo$ = LTRIM$(RTRIM$(nuevaCadena$)) + final$ END FUNCTION   SUB Saludo PRINT "Hola mundo!" END SUB   SUB testCadenas (txt$) FOR cont = 1 TO LEN(txt$) PRINT MID$(txt$, cont, 1); ""; NEXT cont END SUB   SUB testNumeros (a, b, c) PRINT a, b, c END SUB   CALL Saludo PRINT Copialo$("Saludos ", 6, "") PRINT Copialo$("Saludos ", 3, "!!") PRINT CALL testNumeros(1, 2, 3) CALL testNumeros(1, 2, 0) PRINT CALL testCadenas("1, 2, 3, 4, cadena, 6, 7, 8, \'incluye texto\'")
http://rosettacode.org/wiki/Catalan_numbers
Catalan numbers
Catalan numbers You are encouraged to solve this task according to the task description, using any language you may know. Catalan numbers are a sequence of numbers which can be defined directly: C n = 1 n + 1 ( 2 n n ) = ( 2 n ) ! ( n + 1 ) ! n !  for  n ≥ 0. {\displaystyle C_{n}={\frac {1}{n+1}}{2n \choose n}={\frac {(2n)!}{(n+1)!\,n!}}\qquad {\mbox{ for }}n\geq 0.} Or recursively: C 0 = 1 and C n + 1 = ∑ i = 0 n C i C n − i for  n ≥ 0 ; {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n+1}=\sum _{i=0}^{n}C_{i}\,C_{n-i}\quad {\text{for }}n\geq 0;} Or alternatively (also recursive): C 0 = 1 and C n = 2 ( 2 n − 1 ) n + 1 C n − 1 , {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n}={\frac {2(2n-1)}{n+1}}C_{n-1},} Task Implement at least one of these algorithms and print out the first 15 Catalan numbers with each. Memoization   is not required, but may be worth the effort when using the second method above. Related tasks Catalan numbers/Pascal's triangle Evaluate binomial coefficients
#Scheme
Scheme
(define (catalan m) (let loop ((c 1)(n 0)) (if (not (eqv? n m)) (begin (display n)(display ": ")(display c)(newline) (loop (* (/ (* 2 (- (* 2 (+ n 1)) 1)) (+ (+ n 1) 1)) c) (+ n 1) )))))   (catalan 15)
http://rosettacode.org/wiki/Calendar
Calendar
Create a routine that will generate a text calendar for any year. Test the calendar by generating a calendar for the year 1969, on a device of the time. Choose one of the following devices: A line printer with a width of 132 characters. An IBM 3278 model 4 terminal (80×43 display with accented characters). Target formatting the months of the year to fit nicely across the 80 character width screen. Restrict number of lines in test output to 43. (Ideally, the program will generate well-formatted calendars for any page width from 20 characters up.) Kudos (κῦδος) for routines that also transition from Julian to Gregorian calendar. This task is inspired by Real Programmers Don't Use PASCAL by Ed Post, Datamation, volume 29 number 7, July 1983. THE REAL PROGRAMMER'S NATURAL HABITAT "Taped to the wall is a line-printer Snoopy calender for the year 1969." For further Kudos see task CALENDAR, where all code is to be in UPPERCASE. For economy of size, do not actually include Snoopy generation in either the code or the output, instead just output a place-holder. Related task   Five weekends
#Rust
Rust
// Assume your binary name is 'calendar'. // Command line: // >>$ calendar 2019 150 // First argument: year number. // Second argument (optional): text area width (in characters).   extern crate chrono;   use std::{env, cmp}; use chrono::{NaiveDate, Datelike};   const MONTH_WIDTH: usize = 22;   fn print_header(months: &[&str]) { const DAYS_OF_WEEK: &str = "SU MO TU WE TH FR SA "; println!(); for m in months { print!("{:^20} ", m); } println!("\n{}", DAYS_OF_WEEK.repeat(months.len())); }   fn get_week_str(days: i32, week_num: i32, start_day_of_week: i32) -> Option<String> { let start = week_num * 7 - start_day_of_week + 1; let end = (week_num + 1) * 7 - start_day_of_week; let mut ret = String::with_capacity(MONTH_WIDTH); if start > days { None } else { for i in start..(end + 1) { if i <= 0 || i > days { ret.push_str(" "); } else { if i < 10 { ret.push_str(" "); } ret.push_str(&i.to_string()); } ret.push_str(" "); } ret.push_str(" "); Some(ret) } }   fn main() { const MONTH_NAMES: [&str; 12] = ["JANUARY", "FEBRUARY", "MARCH", "APRIL", "MAY", "JUNE", "JULY", "AUGUST", "SEPTEMBER", "OCTOBER", "NOVEMBER", "DECEMBER"]; const DEFAULT_TEXT_WIDTH: usize = 100;   let args: Vec<String> = env::args().collect(); let year: i32 = args[1].parse().expect("The first argument must be a year"); let width: usize = if args.len() > 2 { cmp::max(MONTH_WIDTH, args[2].parse().expect("The second argument should be text width")) } else { DEFAULT_TEXT_WIDTH }; let months_in_row = width / MONTH_WIDTH; let month_rows = if MONTH_NAMES.len() % months_in_row == 0 { MONTH_NAMES.len() / months_in_row } else { MONTH_NAMES.len() / months_in_row + 1 };   let start_days_of_week: Vec<i32> = (1..13).map(|x| NaiveDate::from_ymd(year, x, 1).weekday().num_days_from_sunday() as i32).collect();   let month_days: [i32; 12] = if NaiveDate::from_ymd_opt(year, 2, 29).is_some() { [31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31] } else { [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31] };   println!("{year:^w$}", w=width, year=year.to_string()); for i in 0..month_rows { let start = i * months_in_row; let end = cmp::min((i + 1) * months_in_row, MONTH_NAMES.len()); print_header(&MONTH_NAMES[start..end]); let mut count = 0; let mut row_num = 0; while count < months_in_row { let mut row_str = String::with_capacity(width); for j in start..end { match get_week_str(month_days[j], row_num, start_days_of_week[j]) { None => { count += 1; row_str.push_str(&" ".repeat(MONTH_WIDTH)); }, Some(week_str) => row_str.push_str(&week_str) } } if count < months_in_row { println!("{}", row_str); } row_num += 1; } } }  
http://rosettacode.org/wiki/Bulls_and_cows
Bulls and cows
Bulls and Cows Task Create a four digit random number from the digits   1   to   9,   without duplication. The program should:   ask for guesses to this number   reject guesses that are malformed   print the score for the guess The score is computed as: The player wins if the guess is the same as the randomly chosen number, and the program ends. A score of one bull is accumulated for each digit in the guess that equals the corresponding digit in the randomly chosen initial number. A score of one cow is accumulated for each digit in the guess that also appears in the randomly chosen number, but in the wrong position. Related tasks   Bulls and cows/Player   Guess the number   Guess the number/With Feedback   Mastermind
#Nanoquery
Nanoquery
import Nanoquery.Util; random = new(Random)   // a function to verify the user's input def verify_digits(input) global size seen = ""   if len(input) != size return false else for char in input if not char in "0123456789" return false else if char in seen return false end   seen += char end end   return true end   size = 4 chosen = "" while len(chosen) < size digit = random.getInt(8) + 1   if not str(digit) in chosen chosen += str(digit) end end   println "I have chosen a number from 4 unique digits from 1 to 9 arranged in a random order." println "You need to input a 4 digit, unique digit number as a guess at what I have chosen."   guesses = 1 won = false while !won print "\nNext guess [" + str(guesses) + "]: " guess = input()   if !verify_digits(guess) println "Problem, try again. You need to enter 4 unique digits from 1 to 9" else if guess = chosen won = true else bulls = 0 cows = 0 for i in range(0, size - 1) if guess[i] = chosen[i] bulls += 1 else if guess[i] in chosen cows += 1 end end   println format("  %d Bulls\n  %d Cows", bulls, cows) guesses += 1 end end end   println "\nCongratulations you guess correctly in " + guesses + " attempts"
http://rosettacode.org/wiki/Caesar_cipher
Caesar cipher
Task Implement a Caesar cipher, both encoding and decoding. The key is an integer from 1 to 25. This cipher rotates (either towards left or right) the letters of the alphabet (A to Z). The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A). So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC". This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys. Caesar cipher is identical to Vigenère cipher with a key of length 1. Also, Rot-13 is identical to Caesar cipher with key 13. Related tasks Rot-13 Substitution Cipher Vigenère Cipher/Cryptanalysis
#JavaScript
JavaScript
function caesar (text, shift) { return text.toUpperCase().replace(/[^A-Z]/g,'').replace(/./g, function(a) { return String.fromCharCode(65+(a.charCodeAt(0)-65+shift)%26); }); }   // Tests var text = 'veni, vidi, vici'; for (var i = 0; i<26; i++) { console.log(i+': '+caesar(text,i)); }
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#Quackery
Quackery
/O> 123 7 /mod ... Stack: 17 4 /O> 2 pack ... Stack: [ 17 4 ] /O> echo cr ... [ 17 4 ] Stack empty.
http://rosettacode.org/wiki/Catalan_numbers
Catalan numbers
Catalan numbers You are encouraged to solve this task according to the task description, using any language you may know. Catalan numbers are a sequence of numbers which can be defined directly: C n = 1 n + 1 ( 2 n n ) = ( 2 n ) ! ( n + 1 ) ! n !  for  n ≥ 0. {\displaystyle C_{n}={\frac {1}{n+1}}{2n \choose n}={\frac {(2n)!}{(n+1)!\,n!}}\qquad {\mbox{ for }}n\geq 0.} Or recursively: C 0 = 1 and C n + 1 = ∑ i = 0 n C i C n − i for  n ≥ 0 ; {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n+1}=\sum _{i=0}^{n}C_{i}\,C_{n-i}\quad {\text{for }}n\geq 0;} Or alternatively (also recursive): C 0 = 1 and C n = 2 ( 2 n − 1 ) n + 1 C n − 1 , {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n}={\frac {2(2n-1)}{n+1}}C_{n-1},} Task Implement at least one of these algorithms and print out the first 15 Catalan numbers with each. Memoization   is not required, but may be worth the effort when using the second method above. Related tasks Catalan numbers/Pascal's triangle Evaluate binomial coefficients
#Seed7
Seed7
$ include "seed7_05.s7i"; include "bigint.s7i";   const proc: main is func local var bigInteger: n is 0_; begin for n range 0_ to 15_ do writeln((2_ * n) ! n div succ(n)); end for; end func;
http://rosettacode.org/wiki/Calendar
Calendar
Create a routine that will generate a text calendar for any year. Test the calendar by generating a calendar for the year 1969, on a device of the time. Choose one of the following devices: A line printer with a width of 132 characters. An IBM 3278 model 4 terminal (80×43 display with accented characters). Target formatting the months of the year to fit nicely across the 80 character width screen. Restrict number of lines in test output to 43. (Ideally, the program will generate well-formatted calendars for any page width from 20 characters up.) Kudos (κῦδος) for routines that also transition from Julian to Gregorian calendar. This task is inspired by Real Programmers Don't Use PASCAL by Ed Post, Datamation, volume 29 number 7, July 1983. THE REAL PROGRAMMER'S NATURAL HABITAT "Taped to the wall is a line-printer Snoopy calender for the year 1969." For further Kudos see task CALENDAR, where all code is to be in UPPERCASE. For economy of size, do not actually include Snoopy generation in either the code or the output, instead just output a place-holder. Related task   Five weekends
#Scala
Scala
import java.util.{ Calendar, GregorianCalendar } import language.postfixOps import collection.mutable.ListBuffer   object CalendarPrint extends App { val locd = java.util.Locale.getDefault() val cal = new GregorianCalendar val monthsMax = cal.getMaximum(Calendar.MONTH)   def JDKweekDaysToISO(dn: Int) = { val nday = dn - Calendar.MONDAY if (nday < 0) (dn + Calendar.THURSDAY) else nday }   def daysInMonth(year: Int, monthMinusOne: Int): Int = { cal.set(year, monthMinusOne, 1) cal.getActualMaximum(Calendar.DAY_OF_MONTH) }   def namesOfMonths() = { def f1(i: Int): String = { cal.set(2013, i, 1) cal.getDisplayName(Calendar.MONTH, Calendar.LONG, locd) } (0 to monthsMax) map f1 }   def offsets(year: Int): List[Int] = { val months = cal.getMaximum(Calendar.MONTH) def get1stDayOfWeek(i: Int) = { cal.set(year, i, 1) cal.get(Calendar.DAY_OF_WEEK) } (0 to monthsMax).toList map get1stDayOfWeek map { i => JDKweekDaysToISO(i) } }   def headerNameOfDays() = { val mdow = cal.getDisplayNames(Calendar.DAY_OF_WEEK, Calendar.SHORT, locd) // map days of week val it = mdow.keySet.iterator val keySet = new ListBuffer[String] while (it.hasNext) keySet += it.next (keySet.map { key => (JDKweekDaysToISO(mdow.get(key)), key.take(2)) }.sortWith(_._1 < _._1) map (_._2)).mkString(" ") }   def getGregCal(year: Int) = { {   def dayOfMonth(month: Int) = new Iterator[(Int, Int)] { cal.set(year, month, 1) var ldom = 0   def next() = { val res = (cal.get(Calendar.MONTH), cal.get(Calendar.DAY_OF_MONTH)) ldom = res._2 cal.roll(Calendar.DAY_OF_MONTH, true) res }   def hasNext() = (cal.get(Calendar.DAY_OF_MONTH) > ldom) } var ret: List[(Int, Int)] = Nil for (i <- 0 to monthsMax) ret = ret ++ (dayOfMonth(i).toSeq) (ret, offsets(year)) } }   def printCalendar(calendar: (List[(Int, Int)], List[Int]), headerList: List[String] = Nil, printerWidth: Int = 80) = { val mw = 20 // month width val gwf = 2 // gap width fixed val gwm = 2 // gap width minimum val fgw = true   val arr = Array.ofDim[String](6, 7)   def limits(printerWidth: Int): (Int, Int, Int, Int, Int) = { val pw = if (printerWidth < 20) 20 else if (printerWidth > 300) 300 else printerWidth   // months side by side, gaps sum minimum val (msbs, gsm) = { val x1 = { val c = if (pw / mw > 12) 12 else pw / mw val a = (c - 1) if (c * mw + a * gwm <= pw) c else a } match { case 5 => 4 case a if (a > 6 && a < 12) => 6 case other => other } (x1, (x1 - 1) * gwm) }   def getFGW(msbs: Int, gsm: Int) = { val r = (pw - msbs * mw - gsm) / 2; (r, gwf, r) } // fixed gap width def getVGW(msbs: Int, gsm: Int) = pw - msbs * mw - gsm match { // variable gap width case a if (a < 2 * gwm) => (a / 2, gwm, a / 2) case b => { val x = (b + gsm) / (msbs + 1); (x, x, x) } }   // left margin, gap width, right margin val (lm, gw, rm) = if (fgw) getFGW(msbs, gsm) else getVGW(msbs, gsm) (pw, msbs, lm, gw, rm) } // def limits(   val (pw, msbs, lm, gw, rm) = limits(printerWidth) val monthsList = (0 to monthsMax).map { m => calendar._1.filter { _._1 == m } } val nom = namesOfMonths() val hnod = headerNameOfDays   def fsplit(list: List[(Int, Int)]): List[String] = { def fap(p: Int) = (p / 7, p % 7) for (i <- 0 until 6) for (j <- 0 until 7) arr(i)(j) = " " for (i <- 0 until list.size) arr(fap(i + calendar._2(list(i)._1))._1)(fap(i + calendar._2(list(i)._1))._2) = f"${(list(i)._2)}%2d" arr.toList.map(_.foldRight("")(_ + " " + _)) } val monthsRows = monthsList.map(fsplit)   def center(s: String, l: Int): String = { (if (s.size >= l) s else " " * ((l - s.size) / 2) + s + " " * ((l - s.size) / 2) + " ").substring(0, l) }   val maxMonths = monthsMax + 1   val rowblocks = (1 to maxMonths / msbs).map { i => (0 to 5).map { j => val lb = new ListBuffer[String] val k = (i - 1) * msbs (k to k + msbs - 1).map { l => lb += monthsRows(l)(j) } lb } }   val mheaders = (1 to maxMonths / msbs). map { i => (0 to msbs - 1).map { j => center(nom(j + (i - 1) * msbs), 20) } } val dowheaders = (1 to maxMonths / msbs). map { i => (0 to msbs - 1).map { j => center(hnod, 20) } }   headerList.foreach(xs => println(center(xs + '\n', pw))) (1 to 12 / msbs).foreach { i => println(" " * lm + mheaders(i - 1).foldRight("")(_ + " " * gw + _)) println(" " * lm + dowheaders(i - 1).foldRight("")(_ + " " * gw + _)) rowblocks(i - 1).foreach { xs => println(" " * lm + xs.foldRight("")(_ + " " * (gw - 1) + _)) } println } } // def printCal(   printCalendar(getGregCal(1969), List("[Snoopy Picture]", "1969")) printCalendar(getGregCal(1582), List("[Snoopy Picture]", "1582"), printerWidth = 132) }
http://rosettacode.org/wiki/Bulls_and_cows
Bulls and cows
Bulls and Cows Task Create a four digit random number from the digits   1   to   9,   without duplication. The program should:   ask for guesses to this number   reject guesses that are malformed   print the score for the guess The score is computed as: The player wins if the guess is the same as the randomly chosen number, and the program ends. A score of one bull is accumulated for each digit in the guess that equals the corresponding digit in the randomly chosen initial number. A score of one cow is accumulated for each digit in the guess that also appears in the randomly chosen number, but in the wrong position. Related tasks   Bulls and cows/Player   Guess the number   Guess the number/With Feedback   Mastermind
#Nim
Nim
import random, strutils, strformat, sequtils randomize()   const Digits = "123456789" DigitSet = {Digits[0]..Digits[^1]} Size = 4   proc sample(s: string; n: Positive): string = ## Return a random sample of "n" characters extracted from string "s". var s = s s.shuffle() result = s[0..<n]   proc plural(n: int): string = if n > 1: "s" else: ""   let chosen = Digits.sample(Size)   echo &"I have chosen a number from {Size} unique digits from 1 to 9 arranged in a random order." echo &"You need to input a {Size} digit, unique digit number as a guess at what I have chosen."   var guesses = 0 while true: inc guesses var guess = "" while true: stdout.write(&"\nNext guess {guesses}: ") guess = stdin.readLine().strip() if guess.len == Size and allCharsInSet(guess, DigitSet) and guess.deduplicate.len == Size: break echo &"Problem, try again. You need to enter {Size} unique digits from 1 to 9." if guess == chosen: echo &"\nCongratulations! You guessed correctly in {guesses} attempts." break var bulls, cows = 0 for i in 0..<Size: if guess[i] == chosen[i]: inc bulls elif guess[i] in chosen: inc cows echo &" {bulls} Bull{plural(bulls)}\n {cows} Cow{plural(cows)}"
http://rosettacode.org/wiki/Caesar_cipher
Caesar cipher
Task Implement a Caesar cipher, both encoding and decoding. The key is an integer from 1 to 25. This cipher rotates (either towards left or right) the letters of the alphabet (A to Z). The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A). So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC". This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys. Caesar cipher is identical to Vigenère cipher with a key of length 1. Also, Rot-13 is identical to Caesar cipher with key 13. Related tasks Rot-13 Substitution Cipher Vigenère Cipher/Cryptanalysis
#jq
jq
def encrypt(key): . as $s | explode as $xs | (key % 26) as $offset | if $offset == 0 then . else reduce range(0; length) as $i ( {chars: []}; $xs[$i] as $c | .d = $c | if ($c >= 65 and $c <= 90) # 'A' to 'Z' then .d = $c + $offset | if (.d > 90) then .d += -26 else . end else if ($c >= 97 and $c <= 122) # 'a' to 'z' then .d = $c + $offset | if (.d > 122) then .d += -26 else . end else . end end | .chars[$i] = .d ) | .chars | implode end ;   def decrypt(key): encrypt(26 - key);   "Bright vixens jump; dozy fowl quack." | ., (encrypt(8) | ., decrypt(8) )  
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#R
R
### Calling a function that requires no arguments no_args <- function() NULL no_args()     ### Calling a function with a fixed number of arguments fixed_args <- function(x, y) print(paste("x=", x, ", y=", y, sep="")) fixed_args(1, 2) # x=1, y=2 fixed_args(y=2, x=1) # y=1, x=2     ### Calling a function with optional arguments opt_args <- function(x=1) x opt_args() # x=1 opt_args(3.141) # x=3.141     ### Calling a function with a variable number of arguments var_args <- function(...) print(list(...)) var_args(1, 2, 3) var_args(1, c(2,3)) var_args()     ### Calling a function with named arguments fixed_args(y=2, x=1) # x=1, y=2     ### Using a function in statement context if (TRUE) no_args()     ### Using a function in first-class context within an expression print(no_args)     ### Obtaining the return value of a function return_something <- function() 1 x <- return_something() x     ### Distinguishing built-in functions and user-defined functions # Not easily possible. See # http://cran.r-project.org/doc/manuals/R-ints.html#g_t_002eInternal-vs-_002ePrimitive # for details.     ### Distinguishing subroutines and functions # No such distinction.     ### Stating whether arguments are passed by value or by reference # Pass by value.     ### Is partial application possible and how # Yes, see http://rosettacode.org/wiki/Partial_function_application#R
http://rosettacode.org/wiki/Catalan_numbers
Catalan numbers
Catalan numbers You are encouraged to solve this task according to the task description, using any language you may know. Catalan numbers are a sequence of numbers which can be defined directly: C n = 1 n + 1 ( 2 n n ) = ( 2 n ) ! ( n + 1 ) ! n !  for  n ≥ 0. {\displaystyle C_{n}={\frac {1}{n+1}}{2n \choose n}={\frac {(2n)!}{(n+1)!\,n!}}\qquad {\mbox{ for }}n\geq 0.} Or recursively: C 0 = 1 and C n + 1 = ∑ i = 0 n C i C n − i for  n ≥ 0 ; {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n+1}=\sum _{i=0}^{n}C_{i}\,C_{n-i}\quad {\text{for }}n\geq 0;} Or alternatively (also recursive): C 0 = 1 and C n = 2 ( 2 n − 1 ) n + 1 C n − 1 , {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n}={\frac {2(2n-1)}{n+1}}C_{n-1},} Task Implement at least one of these algorithms and print out the first 15 Catalan numbers with each. Memoization   is not required, but may be worth the effort when using the second method above. Related tasks Catalan numbers/Pascal's triangle Evaluate binomial coefficients
#Sidef
Sidef
func f(i) { i==0 ? 1 : (i * f(i-1)) } func c(n) { f(2*n) / f(n) / f(n+1) }
http://rosettacode.org/wiki/Calendar
Calendar
Create a routine that will generate a text calendar for any year. Test the calendar by generating a calendar for the year 1969, on a device of the time. Choose one of the following devices: A line printer with a width of 132 characters. An IBM 3278 model 4 terminal (80×43 display with accented characters). Target formatting the months of the year to fit nicely across the 80 character width screen. Restrict number of lines in test output to 43. (Ideally, the program will generate well-formatted calendars for any page width from 20 characters up.) Kudos (κῦδος) for routines that also transition from Julian to Gregorian calendar. This task is inspired by Real Programmers Don't Use PASCAL by Ed Post, Datamation, volume 29 number 7, July 1983. THE REAL PROGRAMMER'S NATURAL HABITAT "Taped to the wall is a line-printer Snoopy calender for the year 1969." For further Kudos see task CALENDAR, where all code is to be in UPPERCASE. For economy of size, do not actually include Snoopy generation in either the code or the output, instead just output a place-holder. Related task   Five weekends
#Seed7
Seed7
$ include "seed7_05.s7i"; include "time.s7i";   const func string: center (in string: stri, in integer: length) is return ("" lpad (length - length(stri)) div 2 <& stri) rpad length;   const proc: printCalendar (in integer: year, in integer: cols) is func local var time: date is time.value; var integer: dayOfWeek is 0; const array string: monthNames is [] ("January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"); var array array string: monthTable is 12 times 9 times ""; var string: str is ""; var integer: month is 0; var integer: position is 0; var integer: row is 0; var integer: column is 0; var integer: line is 0; begin for month range 1 to 12 do monthTable[month][1] := " " & center(monthNames[month], 20); monthTable[month][2] := " Mo Tu We Th Fr Sa Su"; date := date(year, month, 1); dayOfWeek := dayOfWeek(date); for position range 1 to 43 do if position >= dayOfWeek and position - dayOfWeek < daysInMonth(date.year, date.month) then str := succ(position - dayOfWeek) lpad 3; else str := "" lpad 3; end if; monthTable[month][3 + pred(position) div 7] &:= str; end for; end for; writeln(center("[Snoopy Picture]", cols * 24 + 4)); writeln(center(str(year),cols * 24 + 4)); writeln; for row range 1 to succ(11 div cols) do for line range 1 to 9 do for column range 1 to cols do if pred(row) * cols + column <= 12 then write(" " & monthTable[pred(row) * cols + column][line]); end if; end for; writeln; end for; end for; end func;   const proc: main is func begin printCalendar(1969, 3); end func;
http://rosettacode.org/wiki/Bulls_and_cows
Bulls and cows
Bulls and Cows Task Create a four digit random number from the digits   1   to   9,   without duplication. The program should:   ask for guesses to this number   reject guesses that are malformed   print the score for the guess The score is computed as: The player wins if the guess is the same as the randomly chosen number, and the program ends. A score of one bull is accumulated for each digit in the guess that equals the corresponding digit in the randomly chosen initial number. A score of one cow is accumulated for each digit in the guess that also appears in the randomly chosen number, but in the wrong position. Related tasks   Bulls and cows/Player   Guess the number   Guess the number/With Feedback   Mastermind
#OCaml
OCaml
let rec input () = let s = read_line () in try if String.length s <> 4 then raise Exit; String.iter (function | '1'..'9' -> () | _ -> raise Exit ) s; let t = [ s.[0]; s.[1]; s.[2]; s.[3] ] in let _ = List.fold_left (* reject entry with duplication *) (fun ac b -> if List.mem b ac then raise Exit; (b::ac)) [] t in List.map (fun c -> int_of_string (String.make 1 c)) t with Exit -> prerr_endline "That is an invalid entry. Please try again."; input () ;;   let print_score g t = let bull = ref 0 in List.iter2 (fun x y -> if x = y then incr bull ) g t; let cow = ref 0 in List.iter (fun x -> if List.mem x t then incr cow ) g; cow := !cow - !bull; Printf.printf "%d bulls, %d cows\n%!" !bull !cow ;;   let () = Random.self_init (); let rec mkgoal acc = function 4 -> acc | i -> let n = succ(Random.int 9) in if List.mem n acc then mkgoal acc i else mkgoal (n::acc) (succ i) in let g = mkgoal [] 0 in let found = ref false in while not !found do let t = input () in if t = g then found := true else print_score g t done; print_endline "Congratulations you guessed correctly"; ;;
http://rosettacode.org/wiki/Caesar_cipher
Caesar cipher
Task Implement a Caesar cipher, both encoding and decoding. The key is an integer from 1 to 25. This cipher rotates (either towards left or right) the letters of the alphabet (A to Z). The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A). So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC". This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys. Caesar cipher is identical to Vigenère cipher with a key of length 1. Also, Rot-13 is identical to Caesar cipher with key 13. Related tasks Rot-13 Substitution Cipher Vigenère Cipher/Cryptanalysis
#Jsish
Jsish
/* Caesar cipher, in Jsish */ "use strict";   function caesarCipher(input:string, key:number):string { return input.replace(/([a-z])/g, function(mat, p1, ofs, str) { return Util.fromCharCode((p1.charCodeAt(0) + key + 26 - 97) % 26 + 97); }).replace(/([A-Z])/g, function(mat, p1, ofs, str) { return Util.fromCharCode((p1.charCodeAt(0) + key + 26 - 65) % 26 + 65); }); }   provide('caesarCipher', 1);   if (Interp.conf('unitTest')) { var str = 'The five boxing wizards jump quickly'; ; str; ; 'Enciphered:'; ; caesarCipher(str, 3); ; 'Enciphered then deciphered'; ; caesarCipher(caesarCipher(str, 3), -3); }   /* =!EXPECTSTART!= str ==> The five boxing wizards jump quickly 'Enciphered:' caesarCipher(str, 3) ==> Wkh ilyh eralqj zlcdugv mxps txlfnob 'Enciphered then deciphered' caesarCipher(caesarCipher(str, 3), -3) ==> The five boxing wizards jump quickly =!EXPECTEND!= */
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#Racket
Racket
  #lang racket   ;; Calling a function that requires no arguments (foo)   ;; Calling a function with a fixed number of arguments (foo 1 2 3)   ;; Calling a function with optional arguments ;; Calling a function with a variable number of arguments (foo 1 2 3) ; same in both cases   ;; Calling a function with named arguments (foo 1 2 #:x 3) ; using #:keywords for the names   ;; Using a function in statement context ;; Using a function in first-class context within an expression ;; Obtaining the return value of a function ;; -> Makes no sense for Racket, as well as most other functional PLs   ;; Distinguishing built-in functions and user-defined functions (primitive? foo) ;; but this is mostly useless, since most of Racket is implemented in ;; itself   ;; Distinguishing subroutines and functions ;; -> No difference, though `!' is an idiomatic suffix for names of ;; side-effect functions, and they usually return (void)   ;; Stating whether arguments are passed by value or by reference   ;; -> Always by value, but it's possible to implement languages with ;; other argument passing styles, including passing arguments by ;; reference (eg, there is "#lang algol60")   ;; Is partial application possible and how (curry foo 1 2)  ; later apply this on 3 (λ(x) (foo 1 2 x)) ; a direct way of doing the same  
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#Raku
Raku
foo # as list operator foo() # as function foo.() # as function, explicit postfix form $ref() # as object invocation $ref.() # as object invocation, explicit postfix &foo() # as object invocation &foo.() # as object invocation, explicit postfix ::($name)() # as symbolic ref
http://rosettacode.org/wiki/Catalan_numbers
Catalan numbers
Catalan numbers You are encouraged to solve this task according to the task description, using any language you may know. Catalan numbers are a sequence of numbers which can be defined directly: C n = 1 n + 1 ( 2 n n ) = ( 2 n ) ! ( n + 1 ) ! n !  for  n ≥ 0. {\displaystyle C_{n}={\frac {1}{n+1}}{2n \choose n}={\frac {(2n)!}{(n+1)!\,n!}}\qquad {\mbox{ for }}n\geq 0.} Or recursively: C 0 = 1 and C n + 1 = ∑ i = 0 n C i C n − i for  n ≥ 0 ; {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n+1}=\sum _{i=0}^{n}C_{i}\,C_{n-i}\quad {\text{for }}n\geq 0;} Or alternatively (also recursive): C 0 = 1 and C n = 2 ( 2 n − 1 ) n + 1 C n − 1 , {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n}={\frac {2(2n-1)}{n+1}}C_{n-1},} Task Implement at least one of these algorithms and print out the first 15 Catalan numbers with each. Memoization   is not required, but may be worth the effort when using the second method above. Related tasks Catalan numbers/Pascal's triangle Evaluate binomial coefficients
#smart_BASIC
smart BASIC
PRINT "Recursive:"!PRINT FOR n = 0 TO 15 PRINT n,"#######":catrec(n) NEXT n PRINT!PRINT   PRINT "Non-recursive:"!PRINT FOR n = 0 TO 15 PRINT n,"#######":catnonrec(n) NEXT n   END   DEF catrec(x) IF x = 0 THEN temp = 1 ELSE n = x temp = ((2*((2*n)-1))/(n+1))*catrec(n-1) END IF catrec = temp END DEF   DEF catnonrec(x) temp = 1 FOR n = 1 TO x temp = (2*((2*n)-1))/(n+1)*temp NEXT n catnonrec = temp END DEF
http://rosettacode.org/wiki/Calendar
Calendar
Create a routine that will generate a text calendar for any year. Test the calendar by generating a calendar for the year 1969, on a device of the time. Choose one of the following devices: A line printer with a width of 132 characters. An IBM 3278 model 4 terminal (80×43 display with accented characters). Target formatting the months of the year to fit nicely across the 80 character width screen. Restrict number of lines in test output to 43. (Ideally, the program will generate well-formatted calendars for any page width from 20 characters up.) Kudos (κῦδος) for routines that also transition from Julian to Gregorian calendar. This task is inspired by Real Programmers Don't Use PASCAL by Ed Post, Datamation, volume 29 number 7, July 1983. THE REAL PROGRAMMER'S NATURAL HABITAT "Taped to the wall is a line-printer Snoopy calender for the year 1969." For further Kudos see task CALENDAR, where all code is to be in UPPERCASE. For economy of size, do not actually include Snoopy generation in either the code or the output, instead just output a place-holder. Related task   Five weekends
#Sidef
Sidef
require('DateTime')   define months_per_col = 3 define week_day_names = <Mo Tu We Th Fr Sa Su> define month_names = <Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec>   func fmt_month (year, month) { var str = sprintf("%-20s\n", month_names[month-1]) str += week_day_names.join(' ')+"\n"   var dt = %s<DateTime> var date = dt.new(year => year, month => month) var week_day = date.day_of_week str += (week_day-1 `of` " " -> join(" "))   var last_day = dt.last_day_of_month(year => year, month => month).day for day (date.day .. last_day) { date = dt.new(year => year, month => month, day => day) str += " " if (week_day ~~ (2..7)) if (week_day == 8) { str += "\n" week_day = 1 } str += sprintf("%2d", day) ++week_day } str += " " if (week_day < 8) str += (8-week_day `of` " " -> join(" ")) str += "\n" }   func fmt_year (year) { var month_strs = 12.of {|i| fmt_month(year, i+1).lines }   var str = (' '*30 + year + "\n") for month (0..11 `by` months_per_col) { while (month_strs[month]) { for i (1..months_per_col) { month_strs[month + i - 1] || next str += month_strs[month + i - 1].shift str += ' '*3 } str += "\n" } str += "\n" }   return str }   print fmt_year(ARGV ? Number(ARGV[0]) : 1969)
http://rosettacode.org/wiki/Bulls_and_cows
Bulls and cows
Bulls and Cows Task Create a four digit random number from the digits   1   to   9,   without duplication. The program should:   ask for guesses to this number   reject guesses that are malformed   print the score for the guess The score is computed as: The player wins if the guess is the same as the randomly chosen number, and the program ends. A score of one bull is accumulated for each digit in the guess that equals the corresponding digit in the randomly chosen initial number. A score of one cow is accumulated for each digit in the guess that also appears in the randomly chosen number, but in the wrong position. Related tasks   Bulls and cows/Player   Guess the number   Guess the number/With Feedback   Mastermind
#Oforth
Oforth
: bullsAndCows | numbers guess digits bulls cows |   ListBuffer new ->numbers while(numbers size 4 <>) [ 9 rand dup numbers include ifFalse: [ numbers add ] else: [ drop ] ]   while(true) [ "Enter a number of 4 different digits between 1 and 9 : " print System.Console askln ->digits digits asInteger isNull digits size 4 <> or ifTrue: [ "Number of four digits needed" println continue ] digits map(#asDigit) ->guess   guess numbers zipWith(#==) occurrences(true) ->bulls bulls 4 == ifTrue: [ "You won !" println return ]   guess filter(#[numbers include]) size bulls - ->cows System.Out "Bulls = " << bulls << ", cows = " << cows << cr ] ;
http://rosettacode.org/wiki/Caesar_cipher
Caesar cipher
Task Implement a Caesar cipher, both encoding and decoding. The key is an integer from 1 to 25. This cipher rotates (either towards left or right) the letters of the alphabet (A to Z). The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A). So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC". This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys. Caesar cipher is identical to Vigenère cipher with a key of length 1. Also, Rot-13 is identical to Caesar cipher with key 13. Related tasks Rot-13 Substitution Cipher Vigenère Cipher/Cryptanalysis
#Julia
Julia
  # Caeser cipher # Julia 1.5.4 # author: manuelcaeiro | https://github.com/manuelcaeiro   function csrcipher(text, key) ciphtext = "" for l in text numl = Int(l) ciphnuml = numl + key if numl in 65:90 if ciphnuml > 90 rotciphnuml = ciphnuml - 26 ciphtext = ciphtext * Char(rotciphnuml) else ciphtext = ciphtext * Char(ciphnuml) end elseif numl in 97:122 if ciphnuml > 122 rotciphnuml = ciphnuml - 26 ciphtext = ciphtext * Char(rotciphnuml) else ciphtext = ciphtext * Char(ciphnuml) end else ciphtext = ciphtext * Char(numl) end end return ciphtext end   text = "Magic Encryption"; key = 13 csrcipher(text, key)  
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#REXX
REXX
/*REXX pgms demonstrates various methods/approaches of invoking/calling a REXX function.*/   /*╔════════════════════════════════════════════════════════════════════╗ ║ Calling a function that REQUIRES no arguments. ║ ║ ║ ║ In the REXX language, there is no way to require the caller to not ║ ║ pass arguments, but the programmer can check if any arguments were ║ ║ (or weren't) passed. ║ ╚════════════════════════════════════════════════════════════════════╝*/   yr= yearFunc() /*the function name is caseless if it isn't */ /*enclosed in quotes (') or apostrophes (").*/ say 'year=' yr exit /*stick a fork in it, we're all done. */   yearFunc: procedure /*function ARG returns the # of args.*/ errmsg= '***error***' /*an error message eyecatcher string. */ if arg() \== 0 then say errmsg "the YEARFUNC function won't accept arguments." return left( date('Sorted'), 3)
http://rosettacode.org/wiki/Catalan_numbers
Catalan numbers
Catalan numbers You are encouraged to solve this task according to the task description, using any language you may know. Catalan numbers are a sequence of numbers which can be defined directly: C n = 1 n + 1 ( 2 n n ) = ( 2 n ) ! ( n + 1 ) ! n !  for  n ≥ 0. {\displaystyle C_{n}={\frac {1}{n+1}}{2n \choose n}={\frac {(2n)!}{(n+1)!\,n!}}\qquad {\mbox{ for }}n\geq 0.} Or recursively: C 0 = 1 and C n + 1 = ∑ i = 0 n C i C n − i for  n ≥ 0 ; {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n+1}=\sum _{i=0}^{n}C_{i}\,C_{n-i}\quad {\text{for }}n\geq 0;} Or alternatively (also recursive): C 0 = 1 and C n = 2 ( 2 n − 1 ) n + 1 C n − 1 , {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n}={\frac {2(2n-1)}{n+1}}C_{n-1},} Task Implement at least one of these algorithms and print out the first 15 Catalan numbers with each. Memoization   is not required, but may be worth the effort when using the second method above. Related tasks Catalan numbers/Pascal's triangle Evaluate binomial coefficients
#Standard_ML
Standard ML
(* * val catalan : int -> int * Returns the nth Catalan number. *) fun catalan 0 = 1 | catalan n = ((4 * n - 2) * catalan(n - 1)) div (n + 1);   (* * val print_catalans : int -> unit * Prints out Catalan numbers 0 through 15. *) fun print_catalans(n) = if n > 15 then () else (print (Int.toString(catalan n) ^ "\n"); print_catalans(n + 1)); print_catalans(0); (* * 1 * 1 * 2 * 5 * 14 * 42 * 132 * 429 * 1430 * 4862 * 16796 * 58786 * 208012 * 742900 * 2674440 * 9694845 *)
http://rosettacode.org/wiki/Calendar
Calendar
Create a routine that will generate a text calendar for any year. Test the calendar by generating a calendar for the year 1969, on a device of the time. Choose one of the following devices: A line printer with a width of 132 characters. An IBM 3278 model 4 terminal (80×43 display with accented characters). Target formatting the months of the year to fit nicely across the 80 character width screen. Restrict number of lines in test output to 43. (Ideally, the program will generate well-formatted calendars for any page width from 20 characters up.) Kudos (κῦδος) for routines that also transition from Julian to Gregorian calendar. This task is inspired by Real Programmers Don't Use PASCAL by Ed Post, Datamation, volume 29 number 7, July 1983. THE REAL PROGRAMMER'S NATURAL HABITAT "Taped to the wall is a line-printer Snoopy calender for the year 1969." For further Kudos see task CALENDAR, where all code is to be in UPPERCASE. For economy of size, do not actually include Snoopy generation in either the code or the output, instead just output a place-holder. Related task   Five weekends
#Simula
Simula
BEGIN INTEGER WIDTH, YEAR; INTEGER COLS, LEAD, GAP; TEXT ARRAY WDAYS(0:6); CLASS MONTH(MNAME); TEXT MNAME; BEGIN INTEGER DAYS, START_WDAY, AT_POS; END MONTH; REF(MONTH) ARRAY MONTHS(0:11); WIDTH := 80; YEAR := 1969;   BEGIN TEXT T; INTEGER I, M; FOR T :- "Su", "Mo", "Tu", "We", "Th", "Fr", "Sa" DO BEGIN WDAYS(I) :- T; I := I+1; END; I := 0; FOR T :- "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December" DO BEGIN MONTHS(I) :- NEW MONTH(T); I := I+1; END; I := 0; FOR M := 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 DO BEGIN MONTHS(I).DAYS := M; I := I+1; END; END;   BEGIN   PROCEDURE SPACE(N); INTEGER N; BEGIN WHILE N > 0 DO BEGIN OUTCHAR(' '); N := N-1; END; END SPACE;   PROCEDURE INIT_MONTHS; BEGIN INTEGER I;   IF MOD(YEAR,4) = 0 AND MOD(YEAR,100) <> 0 OR MOD(YEAR,400) = 0 THEN MONTHS(1).DAYS := 29;   YEAR := YEAR-1; MONTHS(0).START_WDAY  := MOD(YEAR * 365 + YEAR//4 - YEAR//100 + YEAR//400 + 1, 7);   FOR I := 1 STEP 1 UNTIL 12-1 DO MONTHS(I).START_WDAY := MOD(MONTHS(I-1).START_WDAY + MONTHS(I-1).DAYS, 7);   COLS := (WIDTH + 2) // 22; WHILE MOD(12,COLS) <> 0 DO COLS := COLS-1; GAP := IF COLS - 1 <> 0 THEN (WIDTH - 20 * COLS) // (COLS - 1) ELSE 0; IF GAP > 4 THEN GAP := 4; LEAD := (WIDTH - (20 + GAP) * COLS + GAP + 1) // 2; YEAR := YEAR+1; END INIT_MONTHS;   PROCEDURE PRINT_ROW(ROW); INTEGER ROW; BEGIN INTEGER C, I, FROM, UP_TO; INTEGER PROCEDURE PREINCREMENT(I); NAME I; INTEGER I; BEGIN I := I+1; PREINCREMENT := I; END PREINCREMENT; INTEGER PROCEDURE POSTINCREMENT(I); NAME I; INTEGER I; BEGIN POSTINCREMENT := I; I := I+1; END POSTINCREMENT; FROM := ROW * COLS; UP_TO := FROM + COLS; SPACE(LEAD); FOR C := FROM STEP 1 UNTIL UP_TO-1 DO BEGIN I := MONTHS(C).MNAME.LENGTH; SPACE((20 - I)//2); OUTTEXT(MONTHS(C).MNAME); SPACE(20 - I - (20 - I)//2 + (IF C = UP_TO - 1 THEN 0 ELSE GAP)); END; OUTIMAGE;   SPACE(LEAD); FOR C := FROM STEP 1 UNTIL UP_TO-1 DO BEGIN FOR I := 0 STEP 1 UNTIL 7-1 DO BEGIN OUTTEXT(WDAYS(I)); OUTTEXT(IF I = 6 THEN "" ELSE " "); END; IF C < UP_TO - 1 THEN SPACE(GAP) ELSE OUTIMAGE; END;   WHILE TRUE DO BEGIN FOR C := FROM STEP 1 UNTIL UP_TO-1 DO IF MONTHS(C).AT_POS < MONTHS(C).DAYS THEN GO TO IBREAK; IBREAK: IF C = UP_TO THEN GO TO OBREAK;   SPACE(LEAD); FOR C := FROM STEP 1 UNTIL UP_TO-1 DO BEGIN FOR I := 0 STEP 1 UNTIL MONTHS(C).START_WDAY-1 DO SPACE(3); WHILE POSTINCREMENT(I) < 7 AND MONTHS(C).AT_POS < MONTHS(C).DAYS DO BEGIN OUTINT(PREINCREMENT(MONTHS(C).AT_POS),2); IF I < 7 OR C < UP_TO - 1 THEN SPACE(1); END; WHILE POSTINCREMENT(I) <= 7 AND C < UP_TO-1 DO SPACE(3); IF C < UP_TO - 1 THEN SPACE(GAP - 1); MONTHS(C).START_WDAY := 0; END; OUTIMAGE; END; OBREAK: OUTIMAGE; END PRINT_ROW;   PROCEDURE PRINT_YEAR; BEGIN INTEGER ROW; TEXT BUF; INTEGER STRLEN; BUF :- BLANKS(32); BUF.PUTINT(YEAR); BUF.SETPOS(1); WHILE BUF.MORE AND THEN BUF.GETCHAR = ' ' DO STRLEN := STRLEN+1; BUF :- BUF.SUB(STRLEN+1, 32-STRLEN); SPACE((WIDTH - BUF.LENGTH) // 2); OUTTEXT(BUF); OUTIMAGE; OUTIMAGE; WHILE ROW * COLS < 12 DO BEGIN PRINT_ROW(ROW); ROW := ROW+1; END; END PRINT_YEAR;   INIT_MONTHS; PRINT_YEAR; END; END;
http://rosettacode.org/wiki/Bulls_and_cows
Bulls and cows
Bulls and Cows Task Create a four digit random number from the digits   1   to   9,   without duplication. The program should:   ask for guesses to this number   reject guesses that are malformed   print the score for the guess The score is computed as: The player wins if the guess is the same as the randomly chosen number, and the program ends. A score of one bull is accumulated for each digit in the guess that equals the corresponding digit in the randomly chosen initial number. A score of one cow is accumulated for each digit in the guess that also appears in the randomly chosen number, but in the wrong position. Related tasks   Bulls and cows/Player   Guess the number   Guess the number/With Feedback   Mastermind
#ooRexx
ooRexx
declare proc {Main} Solution = {PickNUnique 4 {List.number 1 9 1}}   proc {Loop} Guess = {EnterGuess} in {System.showInfo {Bulls Guess Solution}#" bulls and "# {Cows Guess Solution}#" cows"} if Guess \= Solution then {Loop} end end in {Loop} {System.showInfo "You have won!"} end   fun {Bulls Xs Sol} {Length {Filter {List.zip Xs Sol Value.'=='} Id}} end   fun {Cows Xs Sol} {Length {Intersection Xs Sol}} end   local class TextFile from Open.file Open.text end StdIn = {New TextFile init(name:stdin)} in fun {EnterGuess} try {System.printInfo "Enter your guess (e.g. \"1234\"): "} S = {StdIn getS($)} in %% verify {Length S} = 4 {All S Char.isDigit} = true {FD.distinct S} %% assert there is no duplicate digit %% convert from digits to numbers {Map S fun {$ D} D-&0 end} catch _ then {EnterGuess} end end end   fun {PickNUnique N Xs} {FoldL {MakeList N} fun {$ Z _} {Pick {Diff Xs Z}}|Z end nil} end   fun {Pick Xs} {Nth Xs {OS.rand} mod {Length Xs} + 1} end   fun {Diff Xs Ys} {FoldL Ys List.subtract Xs} end   fun {Intersection Xs Ys} {Filter Xs fun {$ X} {Member X Ys} end} end   fun {Id X} X end in {Main}
http://rosettacode.org/wiki/Caesar_cipher
Caesar cipher
Task Implement a Caesar cipher, both encoding and decoding. The key is an integer from 1 to 25. This cipher rotates (either towards left or right) the letters of the alphabet (A to Z). The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A). So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC". This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys. Caesar cipher is identical to Vigenère cipher with a key of length 1. Also, Rot-13 is identical to Caesar cipher with key 13. Related tasks Rot-13 Substitution Cipher Vigenère Cipher/Cryptanalysis
#K
K
  s:"there is a tide in the affairs of men" caesar:{ :[" "=x; x; {x!_ci 97+!26}[y]@_ic[x]-97]}' caesar[s;1] "uifsf jt b ujef jo uif bggbjst pg nfo"  
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#Ring
Ring
  hello() func hello see "Hello from function" + nl  
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#Ruby
Ruby
fn main() { // Rust has a lot of neat things you can do with functions: let's go over the basics first fn no_args() {} // Run function with no arguments no_args();   // Calling a function with fixed number of arguments. // adds_one takes a 32-bit signed integer and returns a 32-bit signed integer fn adds_one(num: i32) -> i32 { // the final expression is used as the return value, though `return` may be used for early returns num + 1 } adds_one(1);   // Optional arguments // The language itself does not support optional arguments, however, you can take advantage of // Rust's algebraic types for this purpose fn prints_argument(maybe: Option<i32>) { match maybe { Some(num) => println!("{}", num), None => println!("No value given"), }; } prints_argument(Some(3)); prints_argument(None);   // You could make this a bit more ergonomic by using Rust's Into trait fn prints_argument_into<I>(maybe: I) where I: Into<Option<i32>> { match maybe.into() { Some(num) => println!("{}", num), None => println!("No value given"), }; } prints_argument_into(3); prints_argument_into(None);   // Rust does not support functions with variable numbers of arguments. Macros fill this niche // (println! as used above is a macro for example)   // Rust does not support named arguments   // We used the no_args function above in a no-statement context   // Using a function in an expression context adds_one(1) + adds_one(5); // evaluates to eight   // Obtain the return value of a function. let two = adds_one(1);   // In Rust there are no real built-in functions (save compiler intrinsics but these must be // manually imported)   // In rust there are no such thing as subroutines   // In Rust, there are three ways to pass an object to a function each of which have very important // distinctions when it comes to Rust's ownership model and move semantics. We may pass by // value, by immutable reference, or mutable reference.   let mut v = vec![1, 2, 3, 4, 5, 6];   // By mutable reference fn add_one_to_first_element(vector: &mut Vec<i32>) { vector[0] += 1; } add_one_to_first_element(&mut v); // By immutable reference fn print_first_element(vector: &Vec<i32>) { println!("{}", vector[0]); } print_first_element(&v);   // By value fn consume_vector(vector: Vec<i32>) { // We can do whatever we want to vector here } consume_vector(v); // Due to Rust's move semantics, v is now inaccessible because it was moved into consume_vector // and was then dropped when it went out of scope   // Partial application is not possible in rust without wrapping the function in another // function/closure e.g.: fn average(x: f64, y: f64) -> f64 { (x + y) / 2.0 } let average_with_four = |y| average(4.0, y); average_with_four(2.0);     }
http://rosettacode.org/wiki/Catalan_numbers
Catalan numbers
Catalan numbers You are encouraged to solve this task according to the task description, using any language you may know. Catalan numbers are a sequence of numbers which can be defined directly: C n = 1 n + 1 ( 2 n n ) = ( 2 n ) ! ( n + 1 ) ! n !  for  n ≥ 0. {\displaystyle C_{n}={\frac {1}{n+1}}{2n \choose n}={\frac {(2n)!}{(n+1)!\,n!}}\qquad {\mbox{ for }}n\geq 0.} Or recursively: C 0 = 1 and C n + 1 = ∑ i = 0 n C i C n − i for  n ≥ 0 ; {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n+1}=\sum _{i=0}^{n}C_{i}\,C_{n-i}\quad {\text{for }}n\geq 0;} Or alternatively (also recursive): C 0 = 1 and C n = 2 ( 2 n − 1 ) n + 1 C n − 1 , {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n}={\frac {2(2n-1)}{n+1}}C_{n-1},} Task Implement at least one of these algorithms and print out the first 15 Catalan numbers with each. Memoization   is not required, but may be worth the effort when using the second method above. Related tasks Catalan numbers/Pascal's triangle Evaluate binomial coefficients
#Stata
Stata
clear set obs 15 gen catalan=1 in 1 replace catalan=catalan[_n-1]*2*(2*_n-3)/_n in 2/l list, noobs noh
http://rosettacode.org/wiki/Calendar
Calendar
Create a routine that will generate a text calendar for any year. Test the calendar by generating a calendar for the year 1969, on a device of the time. Choose one of the following devices: A line printer with a width of 132 characters. An IBM 3278 model 4 terminal (80×43 display with accented characters). Target formatting the months of the year to fit nicely across the 80 character width screen. Restrict number of lines in test output to 43. (Ideally, the program will generate well-formatted calendars for any page width from 20 characters up.) Kudos (κῦδος) for routines that also transition from Julian to Gregorian calendar. This task is inspired by Real Programmers Don't Use PASCAL by Ed Post, Datamation, volume 29 number 7, July 1983. THE REAL PROGRAMMER'S NATURAL HABITAT "Taped to the wall is a line-printer Snoopy calender for the year 1969." For further Kudos see task CALENDAR, where all code is to be in UPPERCASE. For economy of size, do not actually include Snoopy generation in either the code or the output, instead just output a place-holder. Related task   Five weekends
#Smalltalk
Smalltalk
CalendarPrinter printOnTranscriptForYearNumber: 1969
http://rosettacode.org/wiki/Bulls_and_cows
Bulls and cows
Bulls and Cows Task Create a four digit random number from the digits   1   to   9,   without duplication. The program should:   ask for guesses to this number   reject guesses that are malformed   print the score for the guess The score is computed as: The player wins if the guess is the same as the randomly chosen number, and the program ends. A score of one bull is accumulated for each digit in the guess that equals the corresponding digit in the randomly chosen initial number. A score of one cow is accumulated for each digit in the guess that also appears in the randomly chosen number, but in the wrong position. Related tasks   Bulls and cows/Player   Guess the number   Guess the number/With Feedback   Mastermind
#Oz
Oz
declare proc {Main} Solution = {PickNUnique 4 {List.number 1 9 1}}   proc {Loop} Guess = {EnterGuess} in {System.showInfo {Bulls Guess Solution}#" bulls and "# {Cows Guess Solution}#" cows"} if Guess \= Solution then {Loop} end end in {Loop} {System.showInfo "You have won!"} end   fun {Bulls Xs Sol} {Length {Filter {List.zip Xs Sol Value.'=='} Id}} end   fun {Cows Xs Sol} {Length {Intersection Xs Sol}} end   local class TextFile from Open.file Open.text end StdIn = {New TextFile init(name:stdin)} in fun {EnterGuess} try {System.printInfo "Enter your guess (e.g. \"1234\"): "} S = {StdIn getS($)} in %% verify {Length S} = 4 {All S Char.isDigit} = true {FD.distinct S} %% assert there is no duplicate digit %% convert from digits to numbers {Map S fun {$ D} D-&0 end} catch _ then {EnterGuess} end end end   fun {PickNUnique N Xs} {FoldL {MakeList N} fun {$ Z _} {Pick {Diff Xs Z}}|Z end nil} end   fun {Pick Xs} {Nth Xs {OS.rand} mod {Length Xs} + 1} end   fun {Diff Xs Ys} {FoldL Ys List.subtract Xs} end   fun {Intersection Xs Ys} {Filter Xs fun {$ X} {Member X Ys} end} end   fun {Id X} X end in {Main}
http://rosettacode.org/wiki/Caesar_cipher
Caesar cipher
Task Implement a Caesar cipher, both encoding and decoding. The key is an integer from 1 to 25. This cipher rotates (either towards left or right) the letters of the alphabet (A to Z). The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A). So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC". This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys. Caesar cipher is identical to Vigenère cipher with a key of length 1. Also, Rot-13 is identical to Caesar cipher with key 13. Related tasks Rot-13 Substitution Cipher Vigenère Cipher/Cryptanalysis
#Kotlin
Kotlin
// version 1.0.5-2   object Caesar { fun encrypt(s: String, key: Int): String { val offset = key % 26 if (offset == 0) return s var d: Char val chars = CharArray(s.length) for ((index, c) in s.withIndex()) { if (c in 'A'..'Z') { d = c + offset if (d > 'Z') d -= 26 } else if (c in 'a'..'z') { d = c + offset if (d > 'z') d -= 26 } else d = c chars[index] = d } return chars.joinToString("") }   fun decrypt(s: String, key: Int): String { return encrypt(s, 26 - key) } }   fun main(args: Array<String>) { val encoded = Caesar.encrypt("Bright vixens jump; dozy fowl quack.", 8) println(encoded) val decoded = Caesar.decrypt(encoded, 8) println(decoded) }
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#Rust
Rust
fn main() { // Rust has a lot of neat things you can do with functions: let's go over the basics first fn no_args() {} // Run function with no arguments no_args();   // Calling a function with fixed number of arguments. // adds_one takes a 32-bit signed integer and returns a 32-bit signed integer fn adds_one(num: i32) -> i32 { // the final expression is used as the return value, though `return` may be used for early returns num + 1 } adds_one(1);   // Optional arguments // The language itself does not support optional arguments, however, you can take advantage of // Rust's algebraic types for this purpose fn prints_argument(maybe: Option<i32>) { match maybe { Some(num) => println!("{}", num), None => println!("No value given"), }; } prints_argument(Some(3)); prints_argument(None);   // You could make this a bit more ergonomic by using Rust's Into trait fn prints_argument_into<I>(maybe: I) where I: Into<Option<i32>> { match maybe.into() { Some(num) => println!("{}", num), None => println!("No value given"), }; } prints_argument_into(3); prints_argument_into(None);   // Rust does not support functions with variable numbers of arguments. Macros fill this niche // (println! as used above is a macro for example)   // Rust does not support named arguments   // We used the no_args function above in a no-statement context   // Using a function in an expression context adds_one(1) + adds_one(5); // evaluates to eight   // Obtain the return value of a function. let two = adds_one(1);   // In Rust there are no real built-in functions (save compiler intrinsics but these must be // manually imported)   // In rust there are no such thing as subroutines   // In Rust, there are three ways to pass an object to a function each of which have very important // distinctions when it comes to Rust's ownership model and move semantics. We may pass by // value, by immutable reference, or mutable reference.   let mut v = vec![1, 2, 3, 4, 5, 6];   // By mutable reference fn add_one_to_first_element(vector: &mut Vec<i32>) { vector[0] += 1; } add_one_to_first_element(&mut v); // By immutable reference fn print_first_element(vector: &Vec<i32>) { println!("{}", vector[0]); } print_first_element(&v);   // By value fn consume_vector(vector: Vec<i32>) { // We can do whatever we want to vector here } consume_vector(v); // Due to Rust's move semantics, v is now inaccessible because it was moved into consume_vector // and was then dropped when it went out of scope   // Partial application is not possible in rust without wrapping the function in another // function/closure e.g.: fn average(x: f64, y: f64) -> f64 { (x + y) / 2.0 } let average_with_four = |y| average(4.0, y); average_with_four(2.0);     }
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#Scala
Scala
def ??? = throw new NotImplementedError // placeholder for implementation of hypothetical methods def myFunction0() = ??? myFunction0() // function invoked with empty parameter list myFunction0 // function invoked with empty parameter list omitted   def myFunction = ??? myFunction // function invoked with no arguments or empty arg list /* myFunction() */ // error: does not take parameters   def myFunction1(x: String) = ??? myFunction1("foobar") // function invoked with single argument myFunction1 { "foobar" } // function invoked with single argument provided by a block // (a block of code within {}'s' evaluates to the result of its last expression)   def myFunction2(first: Int, second: String) = ??? val b = "foobar" myFunction2(6, b) // function with two arguments   def multipleArgLists(first: Int)(second: Int, third: String) = ??? multipleArgLists(42)(17, "foobar") // function with three arguments in two argument lists   def myOptionalParam(required: Int, optional: Int = 42) = ??? myOptionalParam(1) // function with optional param myOptionalParam(1, 2) // function with optional param provided   def allParamsOptional(firstOpt: Int = 42, secondOpt: String = "foobar") = ??? allParamsOptional() // function with all optional args /* allParamsOptional */ // error: missing arguments for method allParamsOptional; // follow with `_' if you want to treat it as a partially applied function   def sum[Int](values: Int*) = values.foldLeft(0)((a, b) => a + b) sum(1, 2, 3) // function accepting variable arguments as literal   val values = List(1, 2, 3) sum(values: _*) // function acception variable arguments from collection sum() // function accepting empty variable arguments   def mult(firstValue: Int, otherValues: Int*) = otherValues.foldLeft(firstValue)((a, b) => a * b) mult(1, 2, 3) // function with non-empty variable arguments myOptionalParam(required = 1) // function called with named arguments (all functions have named arguments) myFunction2(second = "foo", first = 1) // function with re-ordered named arguments mult(firstValue = 1, otherValues = 2, 3) // function with named variable argument as literal   val otherValues = Seq(2, 3) mult(1, otherValues = otherValues: _*) // function with named variable argument from collection val result = myFunction0() // function called in an expression context myFunction0() // function called in statement context /* myOptionalParam(optional = 1, 2) */ // error: positional after named argument.   def transform[In, Out](initial: In)(transformation: In => Out) = transformation(initial) val result = transform(42)(x => x * x) // function in first-class context within an expression   def divide(top: Double, bottom: Double) = top / bottom val div = (divide _) // partial application -- defer application of entire arg list val halve = divide(_: Double, 2) // partial application -- defer application of some arguments   class Foo(var value: Int) def incFoo(foo: Foo) = foo.value += 1 // function showing AnyRef's are passed by reference /* def incInt(i: Int) = i += 1 */ // error: += is not a member of Int // (All arguments are passed by reference, but reassignment // or setter must be defined on a type or a field // (respectively) in order to modify its value.)   // No distinction between built-in functions and user-defined functions // No distinction between subroutines and functions
http://rosettacode.org/wiki/Catalan_numbers
Catalan numbers
Catalan numbers You are encouraged to solve this task according to the task description, using any language you may know. Catalan numbers are a sequence of numbers which can be defined directly: C n = 1 n + 1 ( 2 n n ) = ( 2 n ) ! ( n + 1 ) ! n !  for  n ≥ 0. {\displaystyle C_{n}={\frac {1}{n+1}}{2n \choose n}={\frac {(2n)!}{(n+1)!\,n!}}\qquad {\mbox{ for }}n\geq 0.} Or recursively: C 0 = 1 and C n + 1 = ∑ i = 0 n C i C n − i for  n ≥ 0 ; {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n+1}=\sum _{i=0}^{n}C_{i}\,C_{n-i}\quad {\text{for }}n\geq 0;} Or alternatively (also recursive): C 0 = 1 and C n = 2 ( 2 n − 1 ) n + 1 C n − 1 , {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n}={\frac {2(2n-1)}{n+1}}C_{n-1},} Task Implement at least one of these algorithms and print out the first 15 Catalan numbers with each. Memoization   is not required, but may be worth the effort when using the second method above. Related tasks Catalan numbers/Pascal's triangle Evaluate binomial coefficients
#Swift
Swift
func catalan(_ n: Int) -> Int { switch n { case 0: return 1 case _: return catalan(n - 1) * 2 * (2 * n - 1) / (n + 1) } }   for i in 1..<16 { print("catalan(\(i)) => \(catalan(i))") }  
http://rosettacode.org/wiki/Calendar
Calendar
Create a routine that will generate a text calendar for any year. Test the calendar by generating a calendar for the year 1969, on a device of the time. Choose one of the following devices: A line printer with a width of 132 characters. An IBM 3278 model 4 terminal (80×43 display with accented characters). Target formatting the months of the year to fit nicely across the 80 character width screen. Restrict number of lines in test output to 43. (Ideally, the program will generate well-formatted calendars for any page width from 20 characters up.) Kudos (κῦδος) for routines that also transition from Julian to Gregorian calendar. This task is inspired by Real Programmers Don't Use PASCAL by Ed Post, Datamation, volume 29 number 7, July 1983. THE REAL PROGRAMMER'S NATURAL HABITAT "Taped to the wall is a line-printer Snoopy calender for the year 1969." For further Kudos see task CALENDAR, where all code is to be in UPPERCASE. For economy of size, do not actually include Snoopy generation in either the code or the output, instead just output a place-holder. Related task   Five weekends
#SPL
SPL
year = 1969 #.output(#.str(year,">68<")) > row, 0..3 > col, 1..3 cal[col] = mcal(row*3+col,year) size = #.size(cal[col],1) < > i, 1..8 str = "" > col, 1..3  ? col>1, str += " " line = ""  ? #.size(cal[col],1)!<i, line = cal[col][i] str += #.str(line,"<20<") < #.output(str) < < mcal(m,y)= months = ["January","February","March","April","May","June","July","August","September","October","November","December"] days = [31,28,31,30,31,30,31,31,30,31,30,31]  ? y%4=0, days[2] = 29 lines = #.array(0) lines[1] = #.str(months[m],">20<") lines[2] = "Mo Tu We Th Fr Sa Su" n = 3 > i, 1..#.weekday(1,m,y)-1 lines[n] += " " < > d, 1..days[m] wd = #.weekday(d,m,y) lines[n] += #.str(d,">2>")  ? wd<7, lines[n] += " "  ? wd=7, n += 1 < <= lines .
http://rosettacode.org/wiki/Bulls_and_cows
Bulls and cows
Bulls and Cows Task Create a four digit random number from the digits   1   to   9,   without duplication. The program should:   ask for guesses to this number   reject guesses that are malformed   print the score for the guess The score is computed as: The player wins if the guess is the same as the randomly chosen number, and the program ends. A score of one bull is accumulated for each digit in the guess that equals the corresponding digit in the randomly chosen initial number. A score of one cow is accumulated for each digit in the guess that also appears in the randomly chosen number, but in the wrong position. Related tasks   Bulls and cows/Player   Guess the number   Guess the number/With Feedback   Mastermind
#PARI.2FGP
PARI/GP
bc()={ my(u,v,bulls,cows); while(#vecsort(v=vector(4,i,random(9)+1),,8)<4,); while(bulls<4, u=input(); if(type(u)!="t_VEC"|#u!=4,next); bulls=sum(i=1,4,u[i]==v[i]); cows=sum(i=1,4,sum(j=1,4,i!=j&v[i]==u[j])); print("You have "bulls" bulls and "cows" cows") ) };
http://rosettacode.org/wiki/Caesar_cipher
Caesar cipher
Task Implement a Caesar cipher, both encoding and decoding. The key is an integer from 1 to 25. This cipher rotates (either towards left or right) the letters of the alphabet (A to Z). The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A). So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC". This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys. Caesar cipher is identical to Vigenère cipher with a key of length 1. Also, Rot-13 is identical to Caesar cipher with key 13. Related tasks Rot-13 Substitution Cipher Vigenère Cipher/Cryptanalysis
#LabVIEW
LabVIEW
  {def caesar   {def caesar.alphabet {A.split ABCDEFGHIJKLMNOPQRSTUVWXYZ}}   {def caesar.delta {lambda {:s :i :a} {A.get {% {+ {A.in? {A.get :i :a} {caesar.alphabet}} 26 :s} 26} {caesar.alphabet}}}}   {def caesar.loop {lambda {:s :a :b :n :i} {if {> :i :n} then :b else {caesar.r :s  :a {A.set! :i {caesar.delta :s :i :a} :b}  :n {+ :i 1}} }}}   {lambda {:shift :txt} {let { {:s :shift} {:t {S.replace [^A-Z] by in :txt}} } {A.join {caesar.loop :s {A.split :t} {A.new} {- {W.length :t} 1} 0 }}}}} -> caesar     {def text VENI, VIDI, VICI} -> text {S.map {lambda {:i} {br}:i: {caesar :i {text}}} {S.serie 0 26}} ->   0: VENIVIDIVICI 1: WFOJWJEJWJDJ 2: XGPKXKFKXKEK 3: YHQLYLGLYLFL ... 23: SBKFSFAFSFZF 24: TCLGTGBGTGAG 25: UDMHUHCHUHBH 26: VENIVIDIVICI   As a shorter alternative:   {def CAESAR {def CAESAR.rot {lambda {:shift :txt :alpha :i} {A.get {% {+ {A.in? {A.get :i :txt} :alpha} 26 :shift} 26}  :alpha}}} {def CAESAR.loop {lambda {:shift :txt :alpha} {S.map {CAESAR.rot :shift :txt :alpha} {S.serie 0 {- {A.length :txt} 1}}} }} {lambda {:shift :txt} {S.replace \s by in {CAESAR.loop :shift {A.split {S.replace \s by in :txt}} {A.split ABCDEFGHIJKLMNOPQRSTUVWXYZ}} }}} -> CAESAR   {CAESAR 1 VENI VIDI VICI} -> WFOJWJEJWJDJ {CAESAR 25 WFOJWJEJWJDJ} -> VENIVIDIVICI    
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#Seed7
Seed7
put zeroArgsFn()   // Function calls can also be made using the following syntax: put the zeroArgsFn   function zeroArgsFn put "This function was run with zero arguments." return "Return value from zero argument function" end zeroArgsFn
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#SenseTalk
SenseTalk
put zeroArgsFn()   // Function calls can also be made using the following syntax: put the zeroArgsFn   function zeroArgsFn put "This function was run with zero arguments." return "Return value from zero argument function" end zeroArgsFn
http://rosettacode.org/wiki/Catalan_numbers
Catalan numbers
Catalan numbers You are encouraged to solve this task according to the task description, using any language you may know. Catalan numbers are a sequence of numbers which can be defined directly: C n = 1 n + 1 ( 2 n n ) = ( 2 n ) ! ( n + 1 ) ! n !  for  n ≥ 0. {\displaystyle C_{n}={\frac {1}{n+1}}{2n \choose n}={\frac {(2n)!}{(n+1)!\,n!}}\qquad {\mbox{ for }}n\geq 0.} Or recursively: C 0 = 1 and C n + 1 = ∑ i = 0 n C i C n − i for  n ≥ 0 ; {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n+1}=\sum _{i=0}^{n}C_{i}\,C_{n-i}\quad {\text{for }}n\geq 0;} Or alternatively (also recursive): C 0 = 1 and C n = 2 ( 2 n − 1 ) n + 1 C n − 1 , {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n}={\frac {2(2n-1)}{n+1}}C_{n-1},} Task Implement at least one of these algorithms and print out the first 15 Catalan numbers with each. Memoization   is not required, but may be worth the effort when using the second method above. Related tasks Catalan numbers/Pascal's triangle Evaluate binomial coefficients
#Tcl
Tcl
package require Tcl 8.5   # Memoization wrapper proc memoize {function value generator} { variable memoize set key $function,$value if {![info exists memoize($key)]} { set memoize($key) [uplevel 1 $generator] } return $memoize($key) }   # The simplest recursive definition proc tcl::mathfunc::catalan n { if {[incr n 0] < 0} {error "must not be negative"} memoize catalan $n {expr { $n == 0 ? 1 : 2 * (2*$n - 1) * catalan($n - 1) / ($n + 1) }} }
http://rosettacode.org/wiki/Calendar
Calendar
Create a routine that will generate a text calendar for any year. Test the calendar by generating a calendar for the year 1969, on a device of the time. Choose one of the following devices: A line printer with a width of 132 characters. An IBM 3278 model 4 terminal (80×43 display with accented characters). Target formatting the months of the year to fit nicely across the 80 character width screen. Restrict number of lines in test output to 43. (Ideally, the program will generate well-formatted calendars for any page width from 20 characters up.) Kudos (κῦδος) for routines that also transition from Julian to Gregorian calendar. This task is inspired by Real Programmers Don't Use PASCAL by Ed Post, Datamation, volume 29 number 7, July 1983. THE REAL PROGRAMMER'S NATURAL HABITAT "Taped to the wall is a line-printer Snoopy calender for the year 1969." For further Kudos see task CALENDAR, where all code is to be in UPPERCASE. For economy of size, do not actually include Snoopy generation in either the code or the output, instead just output a place-holder. Related task   Five weekends
#Swift
Swift
import Foundation   let monthWidth = 20 let monthGap = 2 let dayNames = "Su Mo Tu We Th Fr Sa" let dateFormatter = DateFormatter() dateFormatter.dateFormat = "MMMM"   func rpad(string: String, width: Int) -> String { return string.count >= width ? string  : String(repeating: " ", count: width - string.count) + string }   func lpad(string: String, width: Int) -> String { return string.count >= width ? string  : string + String(repeating: " ", count: width - string.count) }   func centre(string: String, width: Int) -> String { if string.count >= width { return string } let c = (width - string.count)/2 return String(repeating: " ", count: c) + string + String(repeating: " ", count: width - string.count - c) }   func formatMonth(year: Int, month: Int) -> [String] { let calendar = Calendar.current let dc = DateComponents(year: year, month: month, day: 1) let date = calendar.date(from: dc)! let firstDay = calendar.component(.weekday, from: date) - 1 let range = calendar.range(of: .day, in: .month, for: date)! let daysInMonth = range.count var lines: [String] = [] lines.append(centre(string: dateFormatter.string(from: date), width: monthWidth)) lines.append(dayNames) var padWidth = 2 var line = String(repeating: " ", count: 3 * firstDay) for day in 1...daysInMonth { line += rpad(string: String(day), width: padWidth) padWidth = 3 if (firstDay + day) % 7 == 0 { lines.append(line) line = "" padWidth = 2 } } if line.count > 0 { lines.append(lpad(string: line, width: monthWidth)) } return lines }   func printCentred(string: String, width: Int) { print(rpad(string: string, width: (width + string.count)/2)) }   public func printCalendar(year: Int, width: Int) { let months = min(12, max(1, (width + monthGap)/(monthWidth + monthGap))) let lineWidth = monthWidth * months + monthGap * (months - 1) printCentred(string: "[Snoopy]", width: lineWidth) printCentred(string: String(year), width: lineWidth) var firstMonth = 1 while firstMonth <= 12 { if firstMonth > 1 { print() } let lastMonth = min(12, firstMonth + months - 1) let monthCount = lastMonth - firstMonth + 1 var lines: [[String]] = [] var lineCount = 0 for month in firstMonth...lastMonth { let monthLines = formatMonth(year: year, month: month) lineCount = max(lineCount, monthLines.count) lines.append(monthLines) } for i in 0..<lineCount { var line = "" for month in 0..<monthCount { if month > 0 { line.append(String(repeating: " ", count: monthGap)) } line.append(i < lines[month].count ? lines[month][i]  : String(repeating: " ", count: monthWidth)) } print(line) } firstMonth = lastMonth + 1 } }   printCalendar(year: 1969, width: 80)
http://rosettacode.org/wiki/Bulls_and_cows
Bulls and cows
Bulls and Cows Task Create a four digit random number from the digits   1   to   9,   without duplication. The program should:   ask for guesses to this number   reject guesses that are malformed   print the score for the guess The score is computed as: The player wins if the guess is the same as the randomly chosen number, and the program ends. A score of one bull is accumulated for each digit in the guess that equals the corresponding digit in the randomly chosen initial number. A score of one cow is accumulated for each digit in the guess that also appears in the randomly chosen number, but in the wrong position. Related tasks   Bulls and cows/Player   Guess the number   Guess the number/With Feedback   Mastermind
#Pascal
Pascal
Program BullCow;   {$mode objFPC}   uses Math, SysUtils;   type TFourDigit = array[1..4] of integer;   Procedure WriteFourDigit(fd: TFourDigit); { Write out a TFourDigit with no line break following. } var i: integer; begin for i := 1 to 4 do begin Write(fd[i]); end; end;   Function WellFormed(Tentative: TFourDigit): Boolean; { Does the TFourDigit avoid repeating digits? } var current, check: integer; begin   Result := True;   for current := 1 to 4 do begin for check := current + 1 to 4 do begin if Tentative[check] = Tentative[current] then begin Result := False; end; end; end;   end;   Function MakeNumber(): TFourDigit; { Make a random TFourDigit, keeping trying until it is well-formed. } var i: integer; begin for i := 1 to 4 do begin Result[i] := RandomRange(1, 9); end; if not WellFormed(Result) then begin Result := MakeNumber(); end; end;   Function StrToFourDigit(s: string): TFourDigit; { Convert an (input) string to a TFourDigit. } var i: integer; begin for i := 1 to Length(s) do begin StrToFourDigit[i] := StrToInt(s[i]); end; end;   Function Wins(Num, Guess: TFourDigit): Boolean; { Does the guess win? } var i: integer; begin Result := True; for i := 1 to 4 do begin if Num[i] <> Guess[i] then begin Result := False; Exit; end; end; end;   Function GuessScore(Num, Guess: TFourDigit): string; { Represent the score of the current guess as a string. } var i, j, bulls, cows: integer; begin   bulls := 0; cows := 0;   { Count the cows and bulls. } for i := 1 to 4 do begin for j := 1 to 4 do begin if (Num[i] = Guess[j]) then begin { If the indices are the same, that would be a bull. } if (i = j) then begin bulls := bulls + 1; end else begin cows := cows + 1; end; end; end; end;   { Format the result as a sentence. } Result := IntToStr(bulls) + ' bulls, ' + IntToStr(cows) + ' cows.';   end;   Function GetGuess(): TFourDigit; { Get a well-formed user-supplied TFourDigit guess. } var input: string; begin   WriteLn('Enter a guess:'); ReadLn(input);   { Must be 4 digits. } if Length(input) = 4 then begin   Result := StrToFourDigit(input);   if not WellFormed(Result) then begin WriteLn('Four unique digits, please.'); Result := GetGuess(); end;   end else begin WriteLn('Please guess a four-digit number.'); Result := GetGuess(); end;   end;   var Num, Guess: TFourDigit; Turns: integer; begin   { Initialize the randymnity. } Randomize();   { Make the secred number. } Num := MakeNumber();   WriteLn('I have a secret number. Guess it!');   Turns := 0;   { Guess until the user gets it. } While True do begin   Guess := GetGuess();   { Count each guess as a turn. } Turns := Turns + 1;   { If the user won, tell them and ditch. } if Wins(Num, Guess) then begin WriteLn('You won in ' + IntToStr(Turns) + ' tries.'); Write('The number was '); WriteFourDigit(Num); WriteLn('!'); Exit; end else { Otherwise, score it and get a new guess. } begin WriteLn(GuessScore(Num, Guess)); end;   end;   end.  
http://rosettacode.org/wiki/Caesar_cipher
Caesar cipher
Task Implement a Caesar cipher, both encoding and decoding. The key is an integer from 1 to 25. This cipher rotates (either towards left or right) the letters of the alphabet (A to Z). The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A). So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC". This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys. Caesar cipher is identical to Vigenère cipher with a key of length 1. Also, Rot-13 is identical to Caesar cipher with key 13. Related tasks Rot-13 Substitution Cipher Vigenère Cipher/Cryptanalysis
#Lambdatalk
Lambdatalk
  {def caesar   {def caesar.alphabet {A.split ABCDEFGHIJKLMNOPQRSTUVWXYZ}}   {def caesar.delta {lambda {:s :i :a} {A.get {% {+ {A.in? {A.get :i :a} {caesar.alphabet}} 26 :s} 26} {caesar.alphabet}}}}   {def caesar.loop {lambda {:s :a :b :n :i} {if {> :i :n} then :b else {caesar.r :s  :a {A.set! :i {caesar.delta :s :i :a} :b}  :n {+ :i 1}} }}}   {lambda {:shift :txt} {let { {:s :shift} {:t {S.replace [^A-Z] by in :txt}} } {A.join {caesar.loop :s {A.split :t} {A.new} {- {W.length :t} 1} 0 }}}}} -> caesar     {def text VENI, VIDI, VICI} -> text {S.map {lambda {:i} {br}:i: {caesar :i {text}}} {S.serie 0 26}} ->   0: VENIVIDIVICI 1: WFOJWJEJWJDJ 2: XGPKXKFKXKEK 3: YHQLYLGLYLFL ... 23: SBKFSFAFSFZF 24: TCLGTGBGTGAG 25: UDMHUHCHUHBH 26: VENIVIDIVICI   As a shorter alternative:   {def CAESAR {def CAESAR.rot {lambda {:shift :txt :alpha :i} {A.get {% {+ {A.in? {A.get :i :txt} :alpha} 26 :shift} 26}  :alpha}}} {def CAESAR.loop {lambda {:shift :txt :alpha} {S.map {CAESAR.rot :shift :txt :alpha} {S.serie 0 {- {A.length :txt} 1}}} }} {lambda {:shift :txt} {S.replace \s by in {CAESAR.loop :shift {A.split {S.replace \s by in :txt}} {A.split ABCDEFGHIJKLMNOPQRSTUVWXYZ}} }}} -> CAESAR   {CAESAR 1 VENI VIDI VICI} -> WFOJWJEJWJDJ {CAESAR 25 WFOJWJEJWJDJ} -> VENIVIDIVICI    
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#Sidef
Sidef
foo(); # without arguments foo(1, 2); # with two arguments foo(args...); # with a variable number of arguments foo(name: 'Bar', age: 42); # with named arguments   var f = foo; # store the function foo inside 'f' var result = f(); # obtain the return value of a function   var arr = [1,2,3]; foo(arr); # the arguments are passed by object-reference
http://rosettacode.org/wiki/Catalan_numbers
Catalan numbers
Catalan numbers You are encouraged to solve this task according to the task description, using any language you may know. Catalan numbers are a sequence of numbers which can be defined directly: C n = 1 n + 1 ( 2 n n ) = ( 2 n ) ! ( n + 1 ) ! n !  for  n ≥ 0. {\displaystyle C_{n}={\frac {1}{n+1}}{2n \choose n}={\frac {(2n)!}{(n+1)!\,n!}}\qquad {\mbox{ for }}n\geq 0.} Or recursively: C 0 = 1 and C n + 1 = ∑ i = 0 n C i C n − i for  n ≥ 0 ; {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n+1}=\sum _{i=0}^{n}C_{i}\,C_{n-i}\quad {\text{for }}n\geq 0;} Or alternatively (also recursive): C 0 = 1 and C n = 2 ( 2 n − 1 ) n + 1 C n − 1 , {\displaystyle C_{0}=1\quad {\mbox{and}}\quad C_{n}={\frac {2(2n-1)}{n+1}}C_{n-1},} Task Implement at least one of these algorithms and print out the first 15 Catalan numbers with each. Memoization   is not required, but may be worth the effort when using the second method above. Related tasks Catalan numbers/Pascal's triangle Evaluate binomial coefficients
#TI-83_BASIC
TI-83 BASIC
:For(I,1,15 :Disp (2I)!/((I+1)!I! :End
http://rosettacode.org/wiki/Calendar
Calendar
Create a routine that will generate a text calendar for any year. Test the calendar by generating a calendar for the year 1969, on a device of the time. Choose one of the following devices: A line printer with a width of 132 characters. An IBM 3278 model 4 terminal (80×43 display with accented characters). Target formatting the months of the year to fit nicely across the 80 character width screen. Restrict number of lines in test output to 43. (Ideally, the program will generate well-formatted calendars for any page width from 20 characters up.) Kudos (κῦδος) for routines that also transition from Julian to Gregorian calendar. This task is inspired by Real Programmers Don't Use PASCAL by Ed Post, Datamation, volume 29 number 7, July 1983. THE REAL PROGRAMMER'S NATURAL HABITAT "Taped to the wall is a line-printer Snoopy calender for the year 1969." For further Kudos see task CALENDAR, where all code is to be in UPPERCASE. For economy of size, do not actually include Snoopy generation in either the code or the output, instead just output a place-holder. Related task   Five weekends
#Tcl
Tcl
package require Tcl 8.5   # Produce information about the days in a month, without any assumptions about # what those days actually are. proc calMonthDays {timezone locale year month} { set days {} set moment [clock scan [format "%04d-%02d-00 12:00" $year $month] \ -timezone $timezone -locale $locale -format "%Y-%m-%d %H:%M"] while 1 { set moment [clock add $moment 1 day] lassign [clock format $moment -timezone $timezone -locale $locale \ -format "%m %d %u"] m d dow if {[scan $m %d] != $month} { return $days } lappend days $moment [scan $d %d] $dow } }   proc calMonth {year month timezone locale} { set dow 0 set line "" set lines {} foreach {t day dayofweek} [calMonthDays $timezone $locale $year $month] { if {![llength $lines]} {lappend lines $t} if {$dow > $dayofweek} { lappend lines [string trimright $line] set line "" set dow 0 } while {$dow < $dayofweek-1} { append line " " incr dow } append line [format "%2d " $day] set dow $dayofweek } lappend lines [string trimright $line] }   proc cal3Month {year month timezone locale} { # Extract the month data set d1 [lassign [calMonth $year $month $timezone $locale] t1]; incr month set d2 [lassign [calMonth $year $month $timezone $locale] t2]; incr month set d3 [lassign [calMonth $year $month $timezone $locale] t3] # Print the header line of month names foreach t [list $t1 $t2 $t3] { set m [clock format $t -timezone $timezone -locale $locale -format "%B"] set l [expr {10 + [string length $m]/2}] puts -nonewline [format "%-25s" [format "%*s" $l $m]] } puts "" # Print the month days foreach l1 $d1 l2 $d2 l3 $d3 { puts [format "%-25s%-25s%s" $l1 $l2 $l3] } }   proc cal {{year ""} {timezone :localtime} {locale en}} { if {$year eq ""} { set year [clock format [clock seconds] -format %Y] } puts [format "%40s" "-- $year --"] foreach m {1 4 7 10} { puts "" cal3Month $year $m $timezone $locale } }   proc snoopy {} { puts [format "%43s\n" {[Snoopy Picture]}] }   snoopy cal
http://rosettacode.org/wiki/Bulls_and_cows
Bulls and cows
Bulls and Cows Task Create a four digit random number from the digits   1   to   9,   without duplication. The program should:   ask for guesses to this number   reject guesses that are malformed   print the score for the guess The score is computed as: The player wins if the guess is the same as the randomly chosen number, and the program ends. A score of one bull is accumulated for each digit in the guess that equals the corresponding digit in the randomly chosen initial number. A score of one cow is accumulated for each digit in the guess that also appears in the randomly chosen number, but in the wrong position. Related tasks   Bulls and cows/Player   Guess the number   Guess the number/With Feedback   Mastermind
#Perl
Perl
use Data::Random qw(rand_set); use List::MoreUtils qw(uniq);   my $size = 4; my $chosen = join "", rand_set set => ["1".."9"], size => $size;   print "I've chosen a number from $size unique digits from 1 to 9; you need to input $size unique digits to guess my number\n";   for ( my $guesses = 1; ; $guesses++ ) { my $guess; while (1) { print "\nNext guess [$guesses]: "; $guess = <STDIN>; chomp $guess; checkguess($guess) and last; print "$size digits, no repetition, no 0... retry\n"; } if ( $guess eq $chosen ) { print "You did it in $guesses attempts!\n"; last; } my $bulls = 0; my $cows = 0; for my $i (0 .. $size-1) { if ( substr($guess, $i, 1) eq substr($chosen, $i, 1) ) { $bulls++; } elsif ( index($chosen, substr($guess, $i, 1)) >= 0 ) { $cows++; } } print "$cows cows, $bulls bulls\n"; }   sub checkguess { my $g = shift; return uniq(split //, $g) == $size && $g =~ /^[1-9]{$size}$/; }
http://rosettacode.org/wiki/Caesar_cipher
Caesar cipher
Task Implement a Caesar cipher, both encoding and decoding. The key is an integer from 1 to 25. This cipher rotates (either towards left or right) the letters of the alphabet (A to Z). The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A). So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC". This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys. Caesar cipher is identical to Vigenère cipher with a key of length 1. Also, Rot-13 is identical to Caesar cipher with key 13. Related tasks Rot-13 Substitution Cipher Vigenère Cipher/Cryptanalysis
#langur
langur
val .rot = f(.s, .key) { cp2s map(f(.c) rotate(rotate(.c, .key, 'a'..'z'), .key, 'A'..'Z'), s2cp .s) }   val .s = "A quick brown fox jumped over something." val .key = 3   writeln " original: ", .s writeln "encrypted: ", .rot(.s, .key) writeln "decrypted: ", .rot(.rot(.s, .key), -.key)
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#Smalltalk
Smalltalk
f valueWithArguments: arguments.
http://rosettacode.org/wiki/Call_a_function
Call a function
Task Demonstrate the different syntax and semantics provided for calling a function. This may include:   Calling a function that requires no arguments   Calling a function with a fixed number of arguments   Calling a function with optional arguments   Calling a function with a variable number of arguments   Calling a function with named arguments   Using a function in statement context   Using a function in first-class context within an expression   Obtaining the return value of a function   Distinguishing built-in functions and user-defined functions   Distinguishing subroutines and functions   Stating whether arguments are passed by value or by reference   Is partial application possible and how This task is not about defining functions.
#SSEM
SSEM
00110000000000100000000000000000 10. -12 to c 10110000000000000000000000000000 11. 13 to CI 11001111111111111111111111111111 12. -13 11001000000000000000000000000000 13. 19