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http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related tas...
#Ada
Ada
with Ada.Text_Io; use Ada.Text_Io;   procedure Gcd_Test is function Gcd (A, B : Integer) return Integer is M : Integer := A; N : Integer := B; T : Integer; begin while N /= 0 loop T := M; M := N; N := T mod N; end loop; return M; end Gcd;   begin ...
http://rosettacode.org/wiki/Globally_replace_text_in_several_files
Globally replace text in several files
Task Replace every occurring instance of a piece of text in a group of text files with another one. For this task we want to replace the text   "Goodbye London!"   with   "Hello New York!"   for a list of files.
#D
D
import std.file, std.array;   void main() { auto from = "Goodbye London!", to = "Hello, New York!"; foreach (fn; "a.txt b.txt c.txt".split()) { write(fn, replace(cast(string)read(fn), from, to)); } }
http://rosettacode.org/wiki/Globally_replace_text_in_several_files
Globally replace text in several files
Task Replace every occurring instance of a piece of text in a group of text files with another one. For this task we want to replace the text   "Goodbye London!"   with   "Hello New York!"   for a list of files.
#Delphi
Delphi
  program Globally_replace_text_in_several_files;   {$APPTYPE CONSOLE}   uses System.SysUtils, System.IoUtils;   procedure StringReplaceByFile(_old, _new: string; FileName: TFilename; ReplaceFlags: TReplaceFlags = []); overload var Text: string; begin if not FileExists(FileName) then exit; Text := TFile...
http://rosettacode.org/wiki/Hailstone_sequence
Hailstone sequence
The Hailstone sequence of numbers can be generated from a starting positive integer,   n   by:   If   n   is     1     then the sequence ends.   If   n   is   even then the next   n   of the sequence   = n/2   If   n   is   odd   then the next   n   of the sequence   = (3 * n) + 1 The (unproven) Collatz conje...
#APL
APL
  ⍝ recursive dfn: dfnHailstone←{ c←⊃⌽⍵ ⍝ last element 1=c:1 ⍝ if it is 1, stop. ⍵,∇(1+2|c)⊃(c÷2)(1+3×c) ⍝ otherwise pick the next step, and append the result of the recursive call }   ⍝ tradfn version: ∇seq←hailstone n;next ⍝ Returns the hailstone sequence for a given number   seq←n ⍝ Ini...
http://rosettacode.org/wiki/Grayscale_image
Grayscale image
Many image processing algorithms are defined for grayscale (or else monochromatic) images. Task Extend the data storage type defined on this page to support grayscale images. Define two operations, one to convert a color image to a grayscale image and one for the backward conversion. To get luminance of a color u...
#Julia
Julia
  using Color, Images, FixedPointNumbers   const M_RGB_Y = reshape(Color.M_RGB_XYZ[2,:], 3)   function rgb2gray(img::Image) g = red(img)*M_RGB_Y[1] + green(img)*M_RGB_Y[2] + blue(img)*M_RGB_Y[3] g = clamp(g, 0.0, 1.0) return grayim(g) end   function gray2rgb(img::Image) colorspace(img) == "Gray" || retu...
http://rosettacode.org/wiki/Grayscale_image
Grayscale image
Many image processing algorithms are defined for grayscale (or else monochromatic) images. Task Extend the data storage type defined on this page to support grayscale images. Define two operations, one to convert a color image to a grayscale image and one for the backward conversion. To get luminance of a color u...
#Kotlin
Kotlin
// version 1.2.10   import java.io.File import java.awt.image.BufferedImage import javax.imageio.ImageIO   fun BufferedImage.toGrayScale() { for (x in 0 until width) { for (y in 0 until height) { var argb = getRGB(x, y) val alpha = (argb shr 24) and 0xFF val red = (arg...
http://rosettacode.org/wiki/Go_Fish
Go Fish
Write a program to let the user play Go Fish against a computer opponent. Use the following rules: Each player is dealt nine cards to start with. On their turn, a player asks their opponent for a given rank (such as threes or kings). A player must already have at least one card of a given rank to ask for more. If t...
#Lua
Lua
#!/usr/bin/perl   use strict; # https://rosettacode.org/wiki/Go_Fish use warnings; use List::Util qw( first shuffle );   my $pat = qr/[atjqk2-9]/; # ranks my $deck = join '', shuffle map { my $rank = $_; map "$rank$_", qw( S H C D ) } qw( a t j q k ), 2 .. 9;   my $mebooks = my $youbooks = 0;   my $me = substr $deck,...
http://rosettacode.org/wiki/Hamming_numbers
Hamming numbers
Hamming numbers are numbers of the form   H = 2i × 3j × 5k where i, j, k ≥ 0 Hamming numbers   are also known as   ugly numbers   and also   5-smooth numbers   (numbers whose prime divisors are less or equal to 5). Task Generate the sequence of Hamming numbers, in increasing order.   In ...
#DCL
DCL
$ limit = p1 $ $ n = 0 $ h_'n = 1 $ x2 = 2 $ x3 = 3 $ x5 = 5 $ i = 0 $ j = 0 $ k = 0 $ $ n = 1 $ loop: $ x = x2 $ if x3 .lt. x then $ x = x3 $ if x5 .lt. x then $ x = x5 $ h_'n = x $ if x2 .eq. h_'n $ then $ i = i + 1 $ x2 = 2 * h_'i $ endif $ if x3 .eq. h_'n $ then $ j = j + 1 $ x3 = 3 * h_'j $ endif...
http://rosettacode.org/wiki/Guess_the_number
Guess the number
Task Write a program where the program chooses a number between   1   and   10. A player is then prompted to enter a guess.   If the player guesses wrong,   then the prompt appears again until the guess is correct. When the player has made a successful guess the computer will issue a   "Well guessed!"   message,   a...
#Gambas
Gambas
Public Sub Form_Open() Dim byGuess, byGos As Byte Dim byNo As Byte = Rand(1, 10) Dim sHead As String = "Guess the number"   Repeat Inc byGos byGuess = InputBox("Guess the number between 1 and 10", sHead) sHead = "Sorry, have another go" Until byGuess = byNo   Message.Info("Well guessed! You took " & Str(byGos) & ...
http://rosettacode.org/wiki/Guess_the_number
Guess the number
Task Write a program where the program chooses a number between   1   and   10. A player is then prompted to enter a guess.   If the player guesses wrong,   then the prompt appears again until the guess is correct. When the player has made a successful guess the computer will issue a   "Well guessed!"   message,   a...
#GML
GML
var n, g; n = irandom_range(1,10); show_message("I'm thinking of a number from 1 to 10"); g = get_integer("Please enter guess", 1); while(g != n) { g = get_integer("I'm sorry "+g+" is not my number, try again. Please enter guess", 1); } show_message("Well guessed!");
http://rosettacode.org/wiki/Greatest_subsequential_sum
Greatest subsequential sum
Task Given a sequence of integers, find a continuous subsequence which maximizes the sum of its elements, that is, the elements of no other single subsequence add up to a value larger than this one. An empty subsequence is considered to have the sum of   0;   thus if all elements are negative, the result must be th...
#Factor
Factor
USING: kernel locals math math.order sequences ;   :: max-with-index ( elt0 ind0 elt1 ind1 -- elt ind ) elt0 elt1 < [ elt1 ind1 ] [ elt0 ind0 ] if ; : last-of-max ( accseq -- ind ) -1 swap -1 [ max-with-index ] reduce-index nip ;   : max-subseq ( seq -- subseq ) dup 0 [ + 0 max ] accumulate swap suffix last-of-max hea...
http://rosettacode.org/wiki/Greatest_subsequential_sum
Greatest subsequential sum
Task Given a sequence of integers, find a continuous subsequence which maximizes the sum of its elements, that is, the elements of no other single subsequence add up to a value larger than this one. An empty subsequence is considered to have the sum of   0;   thus if all elements are negative, the result must be th...
#Forth
Forth
2variable best variable best-sum   : sum ( array len -- sum ) 0 -rot cells over + swap do i @ + cell +loop ;   : max-sub ( array len -- sub len ) over 0 best 2! 0 best-sum ! dup 1 do \ foreach length 2dup i - 1+ cells over + swap do \ foreach start i j sum dup best-sum @ > if ...
http://rosettacode.org/wiki/Guess_the_number/With_feedback
Guess the number/With feedback
Task Write a game (computer program) that follows the following rules: The computer chooses a number between given set limits. The player is asked for repeated guesses until the the target number is guessed correctly At each guess, the computer responds with whether the guess is: higher than the target, equal to...
#EasyLang
EasyLang
print "Guess a number between 1 and 100!" n = random 100 + 1 repeat g = number input write g if error = 1 print "You must enter a number!" elif g > n print " is too high" elif g < n print " is too low" . until g = n . print " is correct"
http://rosettacode.org/wiki/Greyscale_bars/Display
Greyscale bars/Display
The task is to display a series of vertical greyscale bars (contrast bars) with a sufficient number of bars to span the entire width of the display. For the top quarter of the display, the left hand bar should be black, and we then incrementally step through six shades of grey until we have a white bar on the right ha...
#XPL0
XPL0
include c:\cxpl\codes; \intrinsic 'code' declarations int Q, N, W, B, C, Y; [SetVid($112); \640x480x24 graphics for Q:= 0 to 4-1 do \quarter of screen [N:= 8<<Q; \number of bars W:= 640/N; \width of bar (pixels) for B:= 0 to N-1 do ...
http://rosettacode.org/wiki/Greyscale_bars/Display
Greyscale bars/Display
The task is to display a series of vertical greyscale bars (contrast bars) with a sufficient number of bars to span the entire width of the display. For the top quarter of the display, the left hand bar should be black, and we then incrementally step through six shades of grey until we have a white bar on the right ha...
#Yabasic
Yabasic
open window 1024, 600 w = peek("winwidth") h = peek("winheight") rows = 4 hd = int(h / rows) mitad = 0     for row = 1 to rows if not mitad then wd = int(w / (8 * row)) mitad = wd else mitad = mitad / 2 end if c = 255 / (w / mitad) for n = 0 to (w / mitad) color 255 - c * n, 255 - c * n, 2...
http://rosettacode.org/wiki/Greyscale_bars/Display
Greyscale bars/Display
The task is to display a series of vertical greyscale bars (contrast bars) with a sufficient number of bars to span the entire width of the display. For the top quarter of the display, the left hand bar should be black, and we then incrementally step through six shades of grey until we have a white bar on the right ha...
#zkl
zkl
img:=PPM(640,480); foreach q in ([0..3]){ //quarter of screen n:=(8).shiftLeft(q); //number of bars w:=640/n; //width of bar (pixels) foreach b in ([0..n-1]){ //for each bar... c:=(255.0/(n-1).toFloat() * (if(q.isOdd) n-1-b else b)).toInt(); c:=c.shiftLeft(16) + c.shiftLeft(8) + c; //R...
http://rosettacode.org/wiki/Guess_the_number/With_feedback_(player)
Guess the number/With feedback (player)
Task Write a player for the game that follows the following rules: The scorer will choose a number between set limits. The computer player will print a guess of the target number. The computer asks for a score of whether its guess is higher than, lower than, or equal to the target. The computer guesses, and the score...
#PureBasic
PureBasic
min=0 max=100   If OpenConsole() PrintN("Think of a number between "+Str(min)+" and "+Str(max)+".") PrintN("On every guess of mine you should state whether my guess was") PrintN("too high, too low, or equal to your number by typing 'h', 'l', Or '='") Repeat If max<=min PrintN("I think somthing is stra...
http://rosettacode.org/wiki/Happy_numbers
Happy numbers
From Wikipedia, the free encyclopedia: A happy number is defined by the following process: Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals   1   (where it will stay),   or it loops endlessly in a cycle which does not inclu...
#Euphoria
Euphoria
function is_happy(integer n) sequence seen integer k seen = {} while n > 1 do seen &= n k = 0 while n > 0 do k += power(remainder(n,10),2) n = floor(n/10) end while n = k if find(n,seen) then return 0 end if ...
http://rosettacode.org/wiki/Haversine_formula
Haversine formula
This page uses content from Wikipedia. The original article was at Haversine formula. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance) The haversine formula is an equation important in navigation, g...
#Phix
Phix
function haversine(atom lat1, long1, lat2, long2) constant MER = 6371, -- mean earth radius(km) DEG_TO_RAD = PI/180 lat1 *= DEG_TO_RAD lat2 *= DEG_TO_RAD long1 *= DEG_TO_RAD long2 *= DEG_TO_RAD return MER*arccos(sin(lat1)*sin(lat2)+cos(lat1)*cos(lat2)*cos(long2-long1)) end function ...
http://rosettacode.org/wiki/Hello_world/Text
Hello world/Text
Hello world/Text is part of Short Circuit's Console Program Basics selection. Task Display the string Hello world! on a text console. Related tasks   Hello world/Graphical   Hello world/Line Printer   Hello world/Newbie   Hello world/Newline omission   Hello world/Standard error   Hello world/Web server
#GML
GML
show_message("Hello world!"); // displays a pop-up message show_debug_message("Hello world!"); // sends text to the debug log or IDE
http://rosettacode.org/wiki/Harshad_or_Niven_series
Harshad or Niven series
The Harshad or Niven numbers are positive integers ≥ 1 that are divisible by the sum of their digits. For example,   42   is a Harshad number as   42   is divisible by   (4 + 2)   without remainder. Assume that the series is defined as the numbers in increasing order. Task The task is to create a function/method/...
#PowerShell
PowerShell
  1..1000 | Where { $_ % ( [int[]][string[]][char[]][string]$_ | Measure -Sum ).Sum -eq 0 } | Select -First 20 1001..2000 | Where { $_ % ( [int[]][string[]][char[]][string]$_ | Measure -Sum ).Sum -eq 0 } | Select -First 1  
http://rosettacode.org/wiki/Hello_world/Graphical
Hello world/Graphical
Task Display the string       Goodbye, World!       on a GUI object   (alert box, plain window, text area, etc.). Related task   Hello world/Text
#xTalk
xTalk
answer "Goodbye, World!"
http://rosettacode.org/wiki/Hello_world/Graphical
Hello world/Graphical
Task Display the string       Goodbye, World!       on a GUI object   (alert box, plain window, text area, etc.). Related task   Hello world/Text
#Lobster
Lobster
gl_window("graphical hello world", 800, 600) gl_setfontname("data/fonts/Droid_Sans/DroidSans.ttf") gl_setfontsize(30)   while gl_frame(): gl_clear([ 0.0, 0.0, 0.0, 1.0 ]) gl_text("Goodbye, World!")
http://rosettacode.org/wiki/GUI_component_interaction
GUI component interaction
Almost every application needs to communicate with the user in some way. Therefore, a substantial part of the code deals with the interaction of program logic with GUI components. Typically, the following is needed: put values into input fields under program control read and check input from the user pop up dial...
#Visual_Basic
Visual Basic
VERSION 5.00 Begin VB.Form Form1 Caption = "Form1" ClientHeight = 2265 ClientLeft = 60 ClientTop = 600 ClientWidth = 2175 LinkTopic = "Form1" ScaleHeight = 2265 ScaleWidth = 2175 StartUpPosition = 3 'Windows Default Begin VB.Comm...
http://rosettacode.org/wiki/GUI_component_interaction
GUI component interaction
Almost every application needs to communicate with the user in some way. Therefore, a substantial part of the code deals with the interaction of program logic with GUI components. Typically, the following is needed: put values into input fields under program control read and check input from the user pop up dial...
#Web_68
Web 68
@1Rosetta code program. @aPROGRAM guicomponent CONTEXT VOID USE standard BEGIN @<Included declarations@> @<Modes in the outer reach@> @<Names in the outer reach@> @<Callback procedures@> @<Other routines@> @<Main logic@> END FINISH   @ This file contains all the macros for the Xforms library procedures. Only macros whi...
http://rosettacode.org/wiki/Gray_code
Gray code
Gray code Karnaugh maps Create functions to encode a number to and decode a number from Gray code. Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary). There are many possible Gray codes. The follow...
#CoffeeScript
CoffeeScript
  gray_encode = (n) -> n ^ (n >> 1)   gray_decode = (g) -> n = g n ^= g while g >>= 1 n   for i in [0..32] console.log gray_decode gray_encode(i)  
http://rosettacode.org/wiki/Gray_code
Gray code
Gray code Karnaugh maps Create functions to encode a number to and decode a number from Gray code. Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary). There are many possible Gray codes. The follow...
#Common_Lisp
Common Lisp
(defun gray-encode (n) (logxor n (ash n -1)))   (defun gray-decode (n) (do ((p n (logxor p n))) ((zerop n) p) (setf n (ash n -1))))   (loop for i to 31 do (let* ((g (gray-encode i)) (b (gray-decode g))) (format t "~2d:~6b =>~6b =>~6b :~2d~%" i i g b b)))
http://rosettacode.org/wiki/Get_system_command_output
Get system command output
Task Execute a system command and get its output into the program. The output may be stored in any kind of collection (array, list, etc.). Related task Execute a system command
#F.23
F#
  // System Command Output. Nigel Galloway: October 6th., 2020 let n=new System.Diagnostics.Process(StartInfo=System.Diagnostics.ProcessStartInfo(RedirectStandardOutput=true,RedirectStandardError=true,UseShellExecute=false, FileName= @"C:\Program Files (x86)\Microsoft Visual Studio\2019\BuildTools\Common7\IDE...
http://rosettacode.org/wiki/Get_system_command_output
Get system command output
Task Execute a system command and get its output into the program. The output may be stored in any kind of collection (array, list, etc.). Related task Execute a system command
#Factor
Factor
USING: io.encodings.utf8 io.launcher ; "echo hello" utf8 [ contents ] with-process-reader .
http://rosettacode.org/wiki/Get_system_command_output
Get system command output
Task Execute a system command and get its output into the program. The output may be stored in any kind of collection (array, list, etc.). Related task Execute a system command
#Forth
Forth
s" ps " system \ Output only \ read via pipe into buffer create buffer 266 allot s" ps " r/o open-pipe throw dup buffer swap 256 swap read-file throw swap close-pipe throw drop   buffer swap type \ output is the sa...
http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in t...
#8086_Assembly
8086 Assembly
xchg ax,bx ;exchanges ax with bx   xchg ah,al ;swap the high and low bytes of ax     ;XCHG a register with memory mov dx,0FFFFh mov word ptr [ds:userRam],dx mov si,offset userRam mov ax,1234h xchg ax,[si] ;exchange ax with the value stored at userRam. Now, ax = 0FFFFh and the value stored at userRam = 1234h    ...
http://rosettacode.org/wiki/Greatest_element_of_a_list
Greatest element of a list
Task Create a function that returns the maximum value in a provided set of values, where the number of values may not be known until run-time.
#ARM_Assembly
ARM Assembly
    /* ARM assembly Raspberry PI */ /* program rechMax.s */   /* Constantes */ .equ STDOUT, 1 @ Linux output console .equ EXIT, 1 @ Linux syscall .equ WRITE, 4 @ Linux syscall   /*********************************/ /* Initialized data */ /*********************************/ .data szMess...
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related tas...
#Aime
Aime
o_integer(gcd(33, 77)); o_byte('\n'); o_integer(gcd(49865, 69811)); o_byte('\n');
http://rosettacode.org/wiki/Globally_replace_text_in_several_files
Globally replace text in several files
Task Replace every occurring instance of a piece of text in a group of text files with another one. For this task we want to replace the text   "Goodbye London!"   with   "Hello New York!"   for a list of files.
#Erlang
Erlang
  -module( globally_replace_text ).   -export( [in_files/3, main/1] ).   in_files( Old, New, Files ) when is_list(Old) -> in_files( binary:list_to_bin(Old), binary:list_to_bin(New), Files ); in_files( Old, New, Files ) -> [replace_in_file(Old, New, X, file:read_file(X)) || X <- Files].   main( [Old, New | Files...
http://rosettacode.org/wiki/Hailstone_sequence
Hailstone sequence
The Hailstone sequence of numbers can be generated from a starting positive integer,   n   by:   If   n   is     1     then the sequence ends.   If   n   is   even then the next   n   of the sequence   = n/2   If   n   is   odd   then the next   n   of the sequence   = (3 * n) + 1 The (unproven) Collatz conje...
#AppleScript
AppleScript
on hailstoneSequence(n) script o property sequence : {n} end script   repeat until (n = 1) if (n mod 2 is 0) then set n to n div 2 else set n to 3 * n + 1 end if set end of o's sequence to n end repeat   return o's sequence end hailston...
http://rosettacode.org/wiki/Grayscale_image
Grayscale image
Many image processing algorithms are defined for grayscale (or else monochromatic) images. Task Extend the data storage type defined on this page to support grayscale images. Define two operations, one to convert a color image to a grayscale image and one for the backward conversion. To get luminance of a color u...
#Liberty_BASIC
Liberty BASIC
  nomainwin WindowWidth = 400 WindowHeight = 400 open "Bitmap" for graphics_nf_nsb as #1 h=hwnd(#1) calldll #user32, "GetDC", h as ulong, DC as ulong #1 "trapclose [q]" loadbmp "clr","MLcolor.bmp" #1 "drawbmp clr 1 1;flush" for x = 1 to 150 for y = 1 to 200 calldll #gdi32, "GetPixel", DC as ulong, x as lon...
http://rosettacode.org/wiki/Grayscale_image
Grayscale image
Many image processing algorithms are defined for grayscale (or else monochromatic) images. Task Extend the data storage type defined on this page to support grayscale images. Define two operations, one to convert a color image to a grayscale image and one for the backward conversion. To get luminance of a color u...
#Lingo
Lingo
on rgbToGrayscaleImageFast (img) res = image(img.width, img.height, 8) res.paletteRef = #grayScale res.copyPixels(img, img.rect, img.rect) return res end   on rgbToGrayscaleImageCustom (img) res = image(img.width, img.height, 8) res.paletteRef = #grayScale repeat with x = 0 to img.width-1 repeat with ...
http://rosettacode.org/wiki/Go_Fish
Go Fish
Write a program to let the user play Go Fish against a computer opponent. Use the following rules: Each player is dealt nine cards to start with. On their turn, a player asks their opponent for a given rank (such as threes or kings). A player must already have at least one card of a given rank to ask for more. If t...
#Locomotive_Basic
Locomotive Basic
#!/usr/bin/perl   use strict; # https://rosettacode.org/wiki/Go_Fish use warnings; use List::Util qw( first shuffle );   my $pat = qr/[atjqk2-9]/; # ranks my $deck = join '', shuffle map { my $rank = $_; map "$rank$_", qw( S H C D ) } qw( a t j q k ), 2 .. 9;   my $mebooks = my $youbooks = 0;   my $me = substr $deck,...
http://rosettacode.org/wiki/Hamming_numbers
Hamming numbers
Hamming numbers are numbers of the form   H = 2i × 3j × 5k where i, j, k ≥ 0 Hamming numbers   are also known as   ugly numbers   and also   5-smooth numbers   (numbers whose prime divisors are less or equal to 5). Task Generate the sequence of Hamming numbers, in increasing order.   In ...
#Delphi
Delphi
  note description : "Initial part, in order, of the sequence of Hamming numbers" math : "[ Hamming numbers, also known as regular numbers and 5-smooth numbers, are natural integers that have 2, 3 and 5 as their only prime factors. ]" computer_arithmetic : "[ ...
http://rosettacode.org/wiki/Guess_the_number
Guess the number
Task Write a program where the program chooses a number between   1   and   10. A player is then prompted to enter a guess.   If the player guesses wrong,   then the prompt appears again until the guess is correct. When the player has made a successful guess the computer will issue a   "Well guessed!"   message,   a...
#Go
Go
package main   import ( "fmt" "math/rand" "time" )   func main() { fmt.Print("Guess number from 1 to 10: ") rand.Seed(time.Now().Unix()) n := rand.Intn(10) + 1 for guess := n; ; fmt.Print("No. Try again: ") { switch _, err := fmt.Scan(&guess); { case err != nil: f...
http://rosettacode.org/wiki/Guess_the_number
Guess the number
Task Write a program where the program chooses a number between   1   and   10. A player is then prompted to enter a guess.   If the player guesses wrong,   then the prompt appears again until the guess is correct. When the player has made a successful guess the computer will issue a   "Well guessed!"   message,   a...
#Groovy
Groovy
  def random = new Random() def keyboard = new Scanner(System.in) def number = random.nextInt(10) + 1 println "Guess the number which is between 1 and 10: " def guess = keyboard.nextInt() while (number != guess) { println "Guess again: " guess = keyboard.nextInt() } println "Hurray! You guessed correctly!"  
http://rosettacode.org/wiki/Greatest_subsequential_sum
Greatest subsequential sum
Task Given a sequence of integers, find a continuous subsequence which maximizes the sum of its elements, that is, the elements of no other single subsequence add up to a value larger than this one. An empty subsequence is considered to have the sum of   0;   thus if all elements are negative, the result must be th...
#Fortran
Fortran
program MaxSubSeq implicit none   integer, parameter :: an = 11 integer, dimension(an) :: a = (/ -1, -2, 3, 5, 6, -2, -1, 4, -4, 2, -1 /)   integer, dimension(an,an) :: mix integer :: i, j integer, dimension(2) :: m   forall(i=1:an,j=1:an) mix(i,j) = sum(a(i:j)) m = maxloc(mix) ! a(m(1):m(2)) is the w...
http://rosettacode.org/wiki/Guess_the_number/With_feedback
Guess the number/With feedback
Task Write a game (computer program) that follows the following rules: The computer chooses a number between given set limits. The player is asked for repeated guesses until the the target number is guessed correctly At each guess, the computer responds with whether the guess is: higher than the target, equal to...
#EchoLisp
EchoLisp
  ;;(read <default-value> <prompt>) prompts the user with a default value using the browser dialog box. ;; we play sounds to make this look like an arcade game (lib 'web) ; (play-sound) is defined in web.lib   (define (guess-feed (msg " 🔮 Enter a number in [0...100], -1 to stop.") (n (random 100)) (user 0)) (set! u...
http://rosettacode.org/wiki/Greyscale_bars/Display
Greyscale bars/Display
The task is to display a series of vertical greyscale bars (contrast bars) with a sufficient number of bars to span the entire width of the display. For the top quarter of the display, the left hand bar should be black, and we then incrementally step through six shades of grey until we have a white bar on the right ha...
#ZX_Spectrum_Basic
ZX Spectrum Basic
10 REM wind the colour down or use a black and white television to see greyscale bars 20 REM The ZX Spectrum display is 32 columns wide, so we have 8 columns of 4 spaces 25 BORDER 0: CLS 30 FOR r=0 TO 21: REM There are 22 rows 40 FOR c=0 TO 7: REM We use the native colour sequence here 50 PRINT PAPER c;" ";: REM fou...
http://rosettacode.org/wiki/Guess_the_number/With_feedback_(player)
Guess the number/With feedback (player)
Task Write a player for the game that follows the following rules: The scorer will choose a number between set limits. The computer player will print a guess of the target number. The computer asks for a score of whether its guess is higher than, lower than, or equal to the target. The computer guesses, and the score...
#Python
Python
inclusive_range = mn, mx = (1, 10)   print('''\ Think of a number between %i and %i and wait for me to guess it. On every guess of mine you should state whether the guess was too high, too low, or equal to your number by typing h, l, or = ''' % inclusive_range)   i = 0 while True: i += 1 guess = (mn+mx)//2 ...
http://rosettacode.org/wiki/Happy_numbers
Happy numbers
From Wikipedia, the free encyclopedia: A happy number is defined by the following process: Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals   1   (where it will stay),   or it loops endlessly in a cycle which does not inclu...
#F.23
F#
open System.Collections.Generic open Microsoft.FSharp.Collections   let answer = let sqr x = x*x // Classic square definition let rec AddDigitSquare n = match n with | 0 -> 0 // Sum of squares for ...
http://rosettacode.org/wiki/Haversine_formula
Haversine formula
This page uses content from Wikipedia. The original article was at Haversine formula. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance) The haversine formula is an equation important in navigation, g...
#PHP
PHP
class POI { private $latitude; private $longitude;   public function __construct($latitude, $longitude) { $this->latitude = deg2rad($latitude); $this->longitude = deg2rad($longitude); }   public function getLatitude() { return $this->latitude; }   public function getL...
http://rosettacode.org/wiki/Hello_world/Text
Hello world/Text
Hello world/Text is part of Short Circuit's Console Program Basics selection. Task Display the string Hello world! on a text console. Related tasks   Hello world/Graphical   Hello world/Line Printer   Hello world/Newbie   Hello world/Newline omission   Hello world/Standard error   Hello world/Web server
#Go
Go
package main   import "fmt"   func main() { fmt.Println("Hello world!") }
http://rosettacode.org/wiki/Harshad_or_Niven_series
Harshad or Niven series
The Harshad or Niven numbers are positive integers ≥ 1 that are divisible by the sum of their digits. For example,   42   is a Harshad number as   42   is divisible by   (4 + 2)   without remainder. Assume that the series is defined as the numbers in increasing order. Task The task is to create a function/method/...
#Prolog
Prolog
:- use_module(library(lambda)).   niven :- nb_setval(go, 1),   L = [1 | _], print_niven(L, 1), gen_niven(1, L).     print_niven([X|T], N) :- when(ground(X), ( ( nb_getval(go, 1) -> ( N < 20 -> writeln(X), N1 is N+1, print_niven(T, N1) ; ( X > 1000 -> writeln(X), ...
http://rosettacode.org/wiki/Hello_world/Graphical
Hello world/Graphical
Task Display the string       Goodbye, World!       on a GUI object   (alert box, plain window, text area, etc.). Related task   Hello world/Text
#Logo
Logo
LABEL [Hello, World!] SETLABELHEIGHT 2 * last LABELSIZE LABEL [Goodbye, World!]
http://rosettacode.org/wiki/Hello_world/Graphical
Hello world/Graphical
Task Display the string       Goodbye, World!       on a GUI object   (alert box, plain window, text area, etc.). Related task   Hello world/Text
#Lua
Lua
require "iuplua"   dlg = iup.dialog{iup.label{title="Goodbye, World!"}; title="test"} dlg:show()   if (not iup.MainLoopLevel or iup.MainLoopLevel()==0) then iup.MainLoop() end
http://rosettacode.org/wiki/GUI_component_interaction
GUI component interaction
Almost every application needs to communicate with the user in some way. Therefore, a substantial part of the code deals with the interaction of program logic with GUI components. Typically, the following is needed: put values into input fields under program control read and check input from the user pop up dial...
#Wren
Wren
import "graphics" for Canvas, Color import "input" for Mouse, Keyboard import "dome" for Window import "random" for Random import "./polygon" for Polygon   var Rand = Random.new()   class Button { construct new(x, y, w, h, legend, c, oc, lc) { var vertices = [[x, y], [x+w, y], [x+w, y+h], [x, y+h]] ...
http://rosettacode.org/wiki/Gray_code
Gray code
Gray code Karnaugh maps Create functions to encode a number to and decode a number from Gray code. Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary). There are many possible Gray codes. The follow...
#Component_Pascal
Component Pascal
  MODULE GrayCodes; IMPORT StdLog,SYSTEM;   PROCEDURE Encode*(i: INTEGER; OUT x: INTEGER); VAR j: INTEGER; s,r: SET; BEGIN s := BITS(i);j := MAX(SET); WHILE (j >= 0) & ~(j IN s) DO DEC(j) END; r := {};IF j >= 0 THEN INCL(r,j) END; WHILE j > 0 DO IF ((j IN s) & ~(j - 1 IN s)) OR (~(j IN s) & (j - 1 IN s)) THEN ...
http://rosettacode.org/wiki/Get_system_command_output
Get system command output
Task Execute a system command and get its output into the program. The output may be stored in any kind of collection (array, list, etc.). Related task Execute a system command
#FreeBASIC
FreeBASIC
' FB 1.05.0 Win64   'capture the output of the 'dir' command and print it to a text file   Open "dir_output.txt" For Output As #1 Open Pipe "dir" For Input As #2 Dim li As String   While Not Eof(2) Line Input #2, li Print #1, li Wend   Close #2 Close #1 End
http://rosettacode.org/wiki/Get_system_command_output
Get system command output
Task Execute a system command and get its output into the program. The output may be stored in any kind of collection (array, list, etc.). Related task Execute a system command
#FutureBasic
FutureBasic
  include "NSLog.incl"   local fn ObserverOne( ref as NotificationRef ) FileHandleRef fh = fn NotificationObject( ref ) CFDataRef dta = fn FileHandleAvailableData( fh )   if ( fn DataLength( dta ) > 0 ) CFStringRef string = fn StringWithData( dta, NSUTF8StringEncoding ) NSLog( @"%@", string ) FileHandleWaitForDataIn...
http://rosettacode.org/wiki/Get_system_command_output
Get system command output
Task Execute a system command and get its output into the program. The output may be stored in any kind of collection (array, list, etc.). Related task Execute a system command
#Gambas
Gambas
Public Sub Main() Dim sStore As String   Shell "ls" To sStore Print sStore   End
http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in t...
#8th
8th
  swap  
http://rosettacode.org/wiki/Greatest_element_of_a_list
Greatest element of a list
Task Create a function that returns the maximum value in a provided set of values, where the number of values may not be known until run-time.
#Arturo
Arturo
arr: [5 4 2 9 7 3]   print max arr
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related tas...
#ALGOL_60
ALGOL 60
begin comment Greatest common divisor - algol 60;   integer procedure gcd(m,n); value m,n; integer m,n; begin integer a,b; a:=abs(m); b:=abs(n); if a=0 then gcd:=b else begin integer c,i; for i:=a while b notequal 0 do begin c:=b; ...
http://rosettacode.org/wiki/Globally_replace_text_in_several_files
Globally replace text in several files
Task Replace every occurring instance of a piece of text in a group of text files with another one. For this task we want to replace the text   "Goodbye London!"   with   "Hello New York!"   for a list of files.
#F.23
F#
open System.IO   [<EntryPoint>] let main args = let textFrom = "Goodbye London!" let textTo = "Hello New York!" for name in args do let content = File.ReadAllText(name) let newContent = content.Replace(textFrom, textTo) if content <> newContent then File.WriteAllText(name...
http://rosettacode.org/wiki/Globally_replace_text_in_several_files
Globally replace text in several files
Task Replace every occurring instance of a piece of text in a group of text files with another one. For this task we want to replace the text   "Goodbye London!"   with   "Hello New York!"   for a list of files.
#Factor
Factor
USING: fry io.encodings.utf8 io.files kernel qw sequences splitting ;   : global-replace ( files old new -- ) '[ [ utf8 file-contents _ _ replace ] [ utf8 set-file-contents ] bi ] each ;     qw{ a.txt b.txt c.txt } "Goodbye London!" "Hello New York!" global-replace
http://rosettacode.org/wiki/Globally_replace_text_in_several_files
Globally replace text in several files
Task Replace every occurring instance of a piece of text in a group of text files with another one. For this task we want to replace the text   "Goodbye London!"   with   "Hello New York!"   for a list of files.
#Fortran
Fortran
SUBROUTINE FILEHACK(FNAME,THIS,THAT) !Attacks a file! CHARACTER*(*) FNAME !The name of the file, presumed to contain text. CHARACTER*(*) THIS !The text sought in each record. CHARACTER*(*) THAT !Its replacement, should it be found. INTEGER F,T !Mnemonics for file unit numbers. ...
http://rosettacode.org/wiki/Hailstone_sequence
Hailstone sequence
The Hailstone sequence of numbers can be generated from a starting positive integer,   n   by:   If   n   is     1     then the sequence ends.   If   n   is   even then the next   n   of the sequence   = n/2   If   n   is   odd   then the next   n   of the sequence   = (3 * n) + 1 The (unproven) Collatz conje...
#ARM_Assembly
ARM Assembly
.org 0x08000000   b ProgramStart   ;cartridge header goes here     ; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Program Start   .equ ramarea, 0x02000000 .equ CursorX,ramarea .equ CursorY,ramarea+1 .equ hailstoneram...
http://rosettacode.org/wiki/Grayscale_image
Grayscale image
Many image processing algorithms are defined for grayscale (or else monochromatic) images. Task Extend the data storage type defined on this page to support grayscale images. Define two operations, one to convert a color image to a grayscale image and one for the backward conversion. To get luminance of a color u...
#Lua
Lua
function ConvertToGrayscaleImage( bitmap ) local size_x, size_y = #bitmap, #bitmap[1] local gray_im = {}   for i = 1, size_x do gray_im[i] = {} for j = 1, size_y do gray_im[i][j] = math.floor( 0.2126*bitmap[i][j][1] + 0.7152*bitmap[i][j][2] + 0.0722*bitmap[i][j][3] ) end...
http://rosettacode.org/wiki/Grayscale_image
Grayscale image
Many image processing algorithms are defined for grayscale (or else monochromatic) images. Task Extend the data storage type defined on this page to support grayscale images. Define two operations, one to convert a color image to a grayscale image and one for the backward conversion. To get luminance of a color u...
#Maple
Maple
with(ImageTools): #conversion forward dimensions:=[upperbound(img)]; gray := Matrix(dimensions[1], dimensions[2]); for i from 1 to dimensions[1] do for j from 1 to dimensions[2] do gray[i,j] := 0.2126 * img[i,j,1] + 0.7152*img[i,j,2] + 0.0722*img[i,j,3]: end do: end do: #display the result Embed(Create(gray)): #con...
http://rosettacode.org/wiki/Go_Fish
Go Fish
Write a program to let the user play Go Fish against a computer opponent. Use the following rules: Each player is dealt nine cards to start with. On their turn, a player asks their opponent for a given rank (such as threes or kings). A player must already have at least one card of a given rank to ask for more. If t...
#Mathematica_.2F_Wolfram_Language
Mathematica / Wolfram Language
#!/usr/bin/perl   use strict; # https://rosettacode.org/wiki/Go_Fish use warnings; use List::Util qw( first shuffle );   my $pat = qr/[atjqk2-9]/; # ranks my $deck = join '', shuffle map { my $rank = $_; map "$rank$_", qw( S H C D ) } qw( a t j q k ), 2 .. 9;   my $mebooks = my $youbooks = 0;   my $me = substr $deck,...
http://rosettacode.org/wiki/Hamming_numbers
Hamming numbers
Hamming numbers are numbers of the form   H = 2i × 3j × 5k where i, j, k ≥ 0 Hamming numbers   are also known as   ugly numbers   and also   5-smooth numbers   (numbers whose prime divisors are less or equal to 5). Task Generate the sequence of Hamming numbers, in increasing order.   In ...
#Eiffel
Eiffel
  note description : "Initial part, in order, of the sequence of Hamming numbers" math : "[ Hamming numbers, also known as regular numbers and 5-smooth numbers, are natural integers that have 2, 3 and 5 as their only prime factors. ]" computer_arithmetic : "[ ...
http://rosettacode.org/wiki/Guess_the_number
Guess the number
Task Write a program where the program chooses a number between   1   and   10. A player is then prompted to enter a guess.   If the player guesses wrong,   then the prompt appears again until the guess is correct. When the player has made a successful guess the computer will issue a   "Well guessed!"   message,   a...
#GW-BASIC
GW-BASIC
10 RANDOMIZE TIMER:N=INT(RND*10+1):G=0 20 PRINT "Guess the number between 1 and 10." 30 WHILE N<>G 40 INPUT "Your guess? ",G 50 WEND 60 PRINT "That's correct!"
http://rosettacode.org/wiki/Guess_the_number
Guess the number
Task Write a program where the program chooses a number between   1   and   10. A player is then prompted to enter a guess.   If the player guesses wrong,   then the prompt appears again until the guess is correct. When the player has made a successful guess the computer will issue a   "Well guessed!"   message,   a...
#Haskell
Haskell
  import Control.Monad import System.Random   -- Repeat the action until the predicate is true. until_ act pred = act >>= pred >>= flip unless (until_ act pred)   answerIs ans guess | ans == guess = putStrLn "You got it!" >> return True | otherwise = putStrLn "Nope. Guess again." >> return False   ask = liftM ...
http://rosettacode.org/wiki/Greatest_subsequential_sum
Greatest subsequential sum
Task Given a sequence of integers, find a continuous subsequence which maximizes the sum of its elements, that is, the elements of no other single subsequence add up to a value larger than this one. An empty subsequence is considered to have the sum of   0;   thus if all elements are negative, the result must be th...
#FreeBASIC
FreeBASIC
' FB 1.05.0 Win64   Dim As Integer seq(10) = {-1 , -2 , 3 , 5 , 6 , -2 , -1 , 4 , -4 , 2 , -1} Dim As Integer i, j, sum, maxSum, first, last   maxSum = 0   For i = LBound(seq) To UBound(seq) sum = 0 For j = i To UBound(seq) ' only proper sub-sequences are considered If i = LBound(seq) AndAlso j = UBound(seq...
http://rosettacode.org/wiki/Guess_the_number/With_feedback
Guess the number/With feedback
Task Write a game (computer program) that follows the following rules: The computer chooses a number between given set limits. The player is asked for repeated guesses until the the target number is guessed correctly At each guess, the computer responds with whether the guess is: higher than the target, equal to...
#Ela
Ela
open string datetime random core monad io   guess () = do putStrLn "What's the upper bound?" ub <- readAny main ub where main ub | ub < 0 = "Bound should be greater than 0." | else = do putStrLn $ format "Guess a number from 1 to {0}" ub dt <- datetime.now ...
http://rosettacode.org/wiki/Guess_the_number/With_feedback_(player)
Guess the number/With feedback (player)
Task Write a player for the game that follows the following rules: The scorer will choose a number between set limits. The computer player will print a guess of the target number. The computer asks for a score of whether its guess is higher than, lower than, or equal to the target. The computer guesses, and the score...
#Quackery
Quackery
  [ [ $ "lower higher equal" nest$ ] constant ] is responses ( --> $ )   [ trim reverse trim reverse $ "" swap witheach [ lower join ] ] is cleanup ( $ --> $ )   [ $ "Think of a number from 1 to" $ " 100 and press enter." join input drop 0...
http://rosettacode.org/wiki/Guess_the_number/With_feedback_(player)
Guess the number/With feedback (player)
Task Write a player for the game that follows the following rules: The scorer will choose a number between set limits. The computer player will print a guess of the target number. The computer asks for a score of whether its guess is higher than, lower than, or equal to the target. The computer guesses, and the score...
#R
R
guessANumberPlayer <- function(low, high) { boundryErrorCheck(low, high) repeat { guess <- floor(mean(c(low, high))) #Invalid inputs to this switch will simply cause the repeat loop to run again, breaking nothing. switch(guessResult(guess), l = low <- guess + 1, h = high <- guess...
http://rosettacode.org/wiki/Happy_numbers
Happy numbers
From Wikipedia, the free encyclopedia: A happy number is defined by the following process: Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals   1   (where it will stay),   or it loops endlessly in a cycle which does not inclu...
#Factor
Factor
USING: combinators kernel make math sequences ;   : squares ( n -- s ) 0 [ over 0 > ] [ [ 10 /mod sq ] dip + ] while nip ;   : (happy?) ( n1 n2 -- ? ) [ squares ] [ squares squares ] bi* { { [ dup 1 = ] [ 2drop t ] } { [ 2dup = ] [ 2drop f ] } [ (happy?) ] } cond ;   : happy? ( n -- ...
http://rosettacode.org/wiki/Haversine_formula
Haversine formula
This page uses content from Wikipedia. The original article was at Haversine formula. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance) The haversine formula is an equation important in navigation, g...
#PicoLisp
PicoLisp
(scl 12) (load "@lib/math.l")   (de haversine (Th1 Ph1 Th2 Ph2) (setq Ph1 (*/ (- Ph1 Ph2) pi 180.0) Th1 (*/ Th1 pi 180.0) Th2 (*/ Th2 pi 180.0) ) (let (DX (- (*/ (cos Ph1) (cos Th1) 1.0) (cos Th2)) DY (*/ (sin Ph1) (cos Th1) 1.0) DZ (- (sin Th1) (sin Th2)) ) (* `(* ...
http://rosettacode.org/wiki/Haversine_formula
Haversine formula
This page uses content from Wikipedia. The original article was at Haversine formula. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance) The haversine formula is an equation important in navigation, g...
#PL.2FI
PL/I
test: procedure options (main); /* 12 January 2014. Derived from Fortran version */ declare d float;   d = haversine(36.12, -86.67, 33.94, -118.40); /* BNA to LAX */ put edit ( 'distance: ', d, ' km') (A, F(10,3)); /* distance: 2887.2600 km */     degrees_to_radians: procedure (degree) returns (float); de...
http://rosettacode.org/wiki/Hello_world/Text
Hello world/Text
Hello world/Text is part of Short Circuit's Console Program Basics selection. Task Display the string Hello world! on a text console. Related tasks   Hello world/Graphical   Hello world/Line Printer   Hello world/Newbie   Hello world/Newline omission   Hello world/Standard error   Hello world/Web server
#Golfscript
Golfscript
"Hello world!"
http://rosettacode.org/wiki/Harshad_or_Niven_series
Harshad or Niven series
The Harshad or Niven numbers are positive integers ≥ 1 that are divisible by the sum of their digits. For example,   42   is a Harshad number as   42   is divisible by   (4 + 2)   without remainder. Assume that the series is defined as the numbers in increasing order. Task The task is to create a function/method/...
#PureBasic
PureBasic
If OpenConsole()=0 : End 1 : EndIf   Procedure.i Niven(v.i) w=v While v : s+v%10 : v/10 : Wend If w%s=0 : ProcedureReturn w : EndIf EndProcedure   Repeat i+1 If Niven(i) : c+1 : Print(Str(i)+" ") : EndIf If c=20 And i<1000 : Print("... ") : i=1000 : EndIf If c=21 : Break : EndIf ForEver   Input()
http://rosettacode.org/wiki/Hello_world/Graphical
Hello world/Graphical
Task Display the string       Goodbye, World!       on a GUI object   (alert box, plain window, text area, etc.). Related task   Hello world/Text
#M2000_Interpreter
M2000 Interpreter
  Module CheckIt { Declare Simple Form \\ we can define form before open Layer Simple { \\ center Window with 12pt font, 12000 twips width and 6000 twips height \\ ; at the end command to center the form in current screen Window 12, 12000, 6000; \\ make ...
http://rosettacode.org/wiki/Hello_world/Graphical
Hello world/Graphical
Task Display the string       Goodbye, World!       on a GUI object   (alert box, plain window, text area, etc.). Related task   Hello world/Text
#Maple
Maple
  Maplets:-Display( Maplets:-Elements:-Maplet( [ "Goodbye, World!" ] ) );  
http://rosettacode.org/wiki/Gray_code
Gray code
Gray code Karnaugh maps Create functions to encode a number to and decode a number from Gray code. Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary). There are many possible Gray codes. The follow...
#Crystal
Crystal
  def gray_encode(bin) bin ^ (bin >> 1) end   def gray_decode(gray) bin = gray while gray > 0 gray >>= 1 bin ^= gray end bin end  
http://rosettacode.org/wiki/Gray_code
Gray code
Gray code Karnaugh maps Create functions to encode a number to and decode a number from Gray code. Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary). There are many possible Gray codes. The follow...
#D
D
uint grayEncode(in uint n) pure nothrow @nogc { return n ^ (n >> 1); }   uint grayDecode(uint n) pure nothrow @nogc { auto p = n; while (n >>= 1) p ^= n; return p; }   void main() { import std.stdio;   " N N2 enc dec2 dec".writeln; foreach (immutable n; 0 .. 32) { ...
http://rosettacode.org/wiki/Get_system_command_output
Get system command output
Task Execute a system command and get its output into the program. The output may be stored in any kind of collection (array, list, etc.). Related task Execute a system command
#Genie
Genie
[indent=4] /* Get system command output, in Genie   valac getSystemCommandOutput.gs ./getSystemCommandOutput */   init try // Blocking with output capture standard_output : string standard_error : string exit_status : int Process.spawn_command_line_sync("sh -c 'ls getSy...
http://rosettacode.org/wiki/Get_system_command_output
Get system command output
Task Execute a system command and get its output into the program. The output may be stored in any kind of collection (array, list, etc.). Related task Execute a system command
#Go
Go
package main   import ( "fmt" "log" "os/exec" )   func main() { output, err := exec.Command("ls", "-l").CombinedOutput() if err != nil { log.Fatal(err) } fmt.Print(string(output)) }
http://rosettacode.org/wiki/Get_system_command_output
Get system command output
Task Execute a system command and get its output into the program. The output may be stored in any kind of collection (array, list, etc.). Related task Execute a system command
#Haskell
Haskell
#!/usr/bin/env stack -- stack --resolver lts-8.15 --install-ghc runghc --package process   import System.Process (readProcess)   main :: IO () main = do -- get the output of the process as a list of lines results <- lines <$> readProcess "hexdump" ["-C", "/etc/passwd"] ""   -- print each line in reverse ...
http://rosettacode.org/wiki/Generic_swap
Generic swap
Task Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types. If your solution language is statically typed please describe the way your language provides genericity. If variables are typed in t...
#ACL2
ACL2
(defun swap (pair) (cons (cdr pair) (car pair)))   (let ((p (cons 1 2))) (cw "Before: ~x0~%After: ~x1~%" p (swap p)))
http://rosettacode.org/wiki/Greatest_element_of_a_list
Greatest element of a list
Task Create a function that returns the maximum value in a provided set of values, where the number of values may not be known until run-time.
#AutoHotkey
AutoHotkey
list = 1,5,17,-2 Loop Parse, list, `, x := x < A_LoopField ? A_LoopField : x MsgBox Max = %x%
http://rosettacode.org/wiki/Greatest_common_divisor
Greatest common divisor
Greatest common divisor You are encouraged to solve this task according to the task description, using any language you may know. Task Find the greatest common divisor   (GCD)   of two integers. Greatest common divisor   is also known as   greatest common factor (gcf)   and   greatest common measure. Related tas...
#ALGOL_68
ALGOL 68
PROC gcd = (INT a, b) INT: ( IF a = 0 THEN b ELIF b = 0 THEN a ELIF a > b THEN gcd(b, a MOD b) ELSE gcd(a, b MOD a) FI ); test:( INT a = 33, b = 77; printf(($x"The gcd of"g" and "g" is "gl$,a,b,gcd(a,b))); INT c = 49865, d = 69811; printf(($x"The gcd of"g" and "g" is "gl$,c,d,gcd...
http://rosettacode.org/wiki/Globally_replace_text_in_several_files
Globally replace text in several files
Task Replace every occurring instance of a piece of text in a group of text files with another one. For this task we want to replace the text   "Goodbye London!"   with   "Hello New York!"   for a list of files.
#FreeBASIC
FreeBASIC
Const matchtext = "Goodbye London!" Const repltext = "Hello New York!" Const matchlen = Len(matchtext)   Dim As Integer x, L0 = 1 dim as string filespec, linein   L0 = 1 While Len(Command(L0)) filespec = Dir(Command(L0)) While Len(filespec) Open filespec For Binary As 1 linein = Space(Lof(1)) ...
http://rosettacode.org/wiki/Globally_replace_text_in_several_files
Globally replace text in several files
Task Replace every occurring instance of a piece of text in a group of text files with another one. For this task we want to replace the text   "Goodbye London!"   with   "Hello New York!"   for a list of files.
#Go
Go
package main   import ( "bytes" "io/ioutil" "log" "os" )   func main() { gRepNFiles("Goodbye London!", "Hello New York!", []string{ "a.txt", "b.txt", "c.txt", }) }   func gRepNFiles(olds, news string, files []string) { oldb := []byte(olds) newb := []byte(news) ...
http://rosettacode.org/wiki/Hailstone_sequence
Hailstone sequence
The Hailstone sequence of numbers can be generated from a starting positive integer,   n   by:   If   n   is     1     then the sequence ends.   If   n   is   even then the next   n   of the sequence   = n/2   If   n   is   odd   then the next   n   of the sequence   = (3 * n) + 1 The (unproven) Collatz conje...
#Arturo
Arturo
hailstone: function [n][ ret: @[n] while [n>1][ if? 1 = and n 1 -> n: 1+3*n else -> n: n/2   'ret ++ n ] ret ]   print "Hailstone sequence for 27:" print hailstone 27   maxHailstoneLength: 0 maxHailstone: 0   loop 2..1000 'x [ l: size hailstone x if l>maxHailstoneLength [ maxHailstoneLength: l maxHailst...
http://rosettacode.org/wiki/Grayscale_image
Grayscale image
Many image processing algorithms are defined for grayscale (or else monochromatic) images. Task Extend the data storage type defined on this page to support grayscale images. Define two operations, one to convert a color image to a grayscale image and one for the backward conversion. To get luminance of a color u...
#Mathematica_.2F_Wolfram_Language
Mathematica / Wolfram Language
toGrayscale[rgb_Image] := ImageApply[#.{0.2126, 0.7152, 0.0722}&, rgb] toFakeRGB[L_Image] := ImageApply[{#, #, #}&, L]
http://rosettacode.org/wiki/Grayscale_image
Grayscale image
Many image processing algorithms are defined for grayscale (or else monochromatic) images. Task Extend the data storage type defined on this page to support grayscale images. Define two operations, one to convert a color image to a grayscale image and one for the backward conversion. To get luminance of a color u...
#MATLAB
MATLAB
function [grayImage] = colortograyscale(inputImage) grayImage = rgb2gray(inputImage);
http://rosettacode.org/wiki/Grayscale_image
Grayscale image
Many image processing algorithms are defined for grayscale (or else monochromatic) images. Task Extend the data storage type defined on this page to support grayscale images. Define two operations, one to convert a color image to a grayscale image and one for the backward conversion. To get luminance of a color u...
#Nim
Nim
  import bitmap import lenientops   type   GrayImage* = object w*, h*: Index pixels*: seq[Luminance]   proc newGrayImage*(width, height: int): GrayImage = ## Create a gray image with given width and height. new(result) result.w = width result.h = height result.pixels.setLen(width * height)   iterato...
http://rosettacode.org/wiki/Go_Fish
Go Fish
Write a program to let the user play Go Fish against a computer opponent. Use the following rules: Each player is dealt nine cards to start with. On their turn, a player asks their opponent for a given rank (such as threes or kings). A player must already have at least one card of a given rank to ask for more. If t...
#Nim
Nim
#!/usr/bin/perl   use strict; # https://rosettacode.org/wiki/Go_Fish use warnings; use List::Util qw( first shuffle );   my $pat = qr/[atjqk2-9]/; # ranks my $deck = join '', shuffle map { my $rank = $_; map "$rank$_", qw( S H C D ) } qw( a t j q k ), 2 .. 9;   my $mebooks = my $youbooks = 0;   my $me = substr $deck,...
http://rosettacode.org/wiki/Hamming_numbers
Hamming numbers
Hamming numbers are numbers of the form   H = 2i × 3j × 5k where i, j, k ≥ 0 Hamming numbers   are also known as   ugly numbers   and also   5-smooth numbers   (numbers whose prime divisors are less or equal to 5). Task Generate the sequence of Hamming numbers, in increasing order.   In ...
#Elixir
Elixir
defmodule Hamming do def generater do queues = [{2, queue}, {3, queue}, {5, queue}] Stream.unfold({1, queues}, fn {n, q} -> next(n, q) end) end   defp next(n, queues) do queues = Enum.map(queues, fn {m, queue} -> {m, push(queue, m*n)} end) min = Enum.map(queues, fn {_, queue} -> top(queue) end)...
http://rosettacode.org/wiki/Guess_the_number
Guess the number
Task Write a program where the program chooses a number between   1   and   10. A player is then prompted to enter a guess.   If the player guesses wrong,   then the prompt appears again until the guess is correct. When the player has made a successful guess the computer will issue a   "Well guessed!"   message,   a...
#HolyC
HolyC
U8 n, *g;   n = 1 + RandU16 % 10;   Print("I'm thinking of a number between 1 and 10.\n"); Print("Try to guess it:\n");   while(1) { g = GetStr;   if (Str2I64(g) == n) { Print("Correct!\n"); break; }   Print("That's not my number. Try another guess:\n"); }
http://rosettacode.org/wiki/Guess_the_number
Guess the number
Task Write a program where the program chooses a number between   1   and   10. A player is then prompted to enter a guess.   If the player guesses wrong,   then the prompt appears again until the guess is correct. When the player has made a successful guess the computer will issue a   "Well guessed!"   message,   a...
#Icon_and_Unicon
Icon and Unicon
procedure main() n := ?10 repeat { writes("Pick a number from 1 through 10: ") if n = numeric(read()) then break } write("Well guessed!") end
http://rosettacode.org/wiki/Greatest_subsequential_sum
Greatest subsequential sum
Task Given a sequence of integers, find a continuous subsequence which maximizes the sum of its elements, that is, the elements of no other single subsequence add up to a value larger than this one. An empty subsequence is considered to have the sum of   0;   thus if all elements are negative, the result must be th...
#Go
Go
package main   import "fmt"   func gss(s []int) ([]int, int) { var best, start, end, sum, sumStart int for i, x := range s { sum += x switch { case sum > best: best = sum start = sumStart end = i + 1 case sum < 0: sum = 0 ...
http://rosettacode.org/wiki/Guess_the_number/With_feedback
Guess the number/With feedback
Task Write a game (computer program) that follows the following rules: The computer chooses a number between given set limits. The player is asked for repeated guesses until the the target number is guessed correctly At each guess, the computer responds with whether the guess is: higher than the target, equal to...
#Elena
Elena
import extensions;   public program() { int randomNumber := randomGenerator.eval(1,10); console.printLine("I'm thinking of a number between 1 and 10. Can you guess it?"); bool numberCorrect := false; until(numberCorrect) { console.print("Guess: "); int userGuess := console.readLine(...