task_url stringlengths 30 116 | task_name stringlengths 2 86 | task_description stringlengths 0 14.4k | language_url stringlengths 2 53 | language_name stringlengths 1 52 | code stringlengths 0 61.9k | response_seed stringclasses 1
value | instruction_seed stringlengths 27 14.4k | _source stringclasses 1
value |
|---|---|---|---|---|---|---|---|---|
http://rosettacode.org/wiki/Empty_directory | Empty directory | Starting with a path to some directory, determine whether the directory is empty.
An empty directory contains no files nor subdirectories.
With Unix or Windows systems, every directory contains an entry for “.” and almost every directory contains “..” (except for a root directory); an empty directory contains no other... | #OCaml | OCaml | let is_dir_empty d =
Sys.readdir d = [| |] | Give a code snippet in #OCaml
Starting with a path to some directory, determine whether the directory is empty.
An empty directory contains no files nor subdirectories.
With Unix or Windows systems, every directory contains an entry for “.” and almost every directory contains “..” (except for a root directory); an em... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Function_definition | Function definition | A function is a body of code that returns a value.
The value returned may depend on arguments provided to the function.
Task
Write a definition of a function called "multiply" that takes two arguments and returns their product.
(Argument types should be chosen so as not to distract from showing how functions are ... | #Fish | Fish | 2[*] | Give a code snippet in #Fish
A function is a body of code that returns a value.
The value returned may depend on arguments provided to the function.
Task
Write a definition of a function called "multiply" that takes two arguments and returns their product.
(Argument types should be chosen so as not to distract f... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/Infinite | Loops/Infinite | Task
Print out SPAM followed by a newline in an infinite loop.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downward for
Loops/For
Loops/For with a specified step
Loops/Foreach
Loops/Increment loop index within l... | #Jsish | Jsish | for (;;) puts('SPAM'); | Give a code snippet in #Jsish
Task
Print out SPAM followed by a newline in an infinite loop.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downward for
Loops/For
Loops/For with a specified step
Loops/Foreach
Loop... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Palindrome_detection | Palindrome detection | A palindrome is a phrase which reads the same backward and forward.
Task[edit]
Write a function or program that checks whether a given sequence of characters (or, if you prefer, bytes)
is a palindrome.
For extra credit:
Support Unicode characters.
Write a second function (possibly as a wrapper to the first) which ... | #AppleScript | AppleScript | use framework "Foundation"
------ CASE-INSENSITIVE PALINDROME, IGNORING SPACES ? ----
-- isPalindrome :: String -> Bool
on isPalindrome(s)
s = intercalate("", reverse of characters of s)
end isPalindrome
-- toSpaceFreeLower :: String -> String
on spaceFreeToLower(s)
script notSpace
on |λ|(s)
... | Give a code snippet in #AppleScript
A palindrome is a phrase which reads the same backward and forward.
Task[edit]
Write a function or program that checks whether a given sequence of characters (or, if you prefer, bytes)
is a palindrome.
For extra credit:
Support Unicode characters.
Write a second function (possi... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Semiprime | Semiprime | Semiprime numbers are natural numbers that are products of exactly two (possibly equal) prime numbers.
Semiprimes are also known as:
semi-primes
biprimes
bi-primes
2-almost primes
or simply: P2
Example
1679 = 23 × 73
(This particular number was chosen as the length of the Arecib... | #C.23 | C# |
static void Main(string[] args)
{
//test some numbers
for (int i = 0; i < 50; i++)
{
Console.WriteLine("{0}\t{1} ", i,isSemiPrime(i));
}
Console.ReadLine();
}
//returns true or false depending if input was considered semiprime
private static bool isSemiPrime(int c)
{
int a = 2, b = 0... | Give a code snippet in #C.23
Semiprime numbers are natural numbers that are products of exactly two (possibly equal) prime numbers.
Semiprimes are also known as:
semi-primes
biprimes
bi-primes
2-almost primes
or simply: P2
Example
1679 = 23 × 73
(This particular number was chos... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Yin_and_yang | Yin and yang | One well-known symbol of the philosophy of duality known as yin and yang is the taijitu.
Task
Create a function that, given a parameter representing size, generates such a symbol scaled to the requested size.
Generate and display the symbol for two different (small) sizes.
| #zkl | zkl | fcn draw_yinyang(trans,scale){
0'|<use xlink:href="#y" transform="translate(%d,%d) scale(%g)"/>|
.fmt(trans,trans,scale).print();
}
print(
"<?xml version='1.0' encoding='UTF-8' standalone='no'?>\n"
"<!DOCTYPE svg PUBLIC '-//W3C//DTD SVG 1.1//EN'\n"
" 'http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd'>\n"
"<svg ... | Give a code snippet in #zkl
One well-known symbol of the philosophy of duality known as yin and yang is the taijitu.
Task
Create a function that, given a parameter representing size, generates such a symbol scaled to the requested size.
Generate and display the symbol for two different (small) sizes.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Array_concatenation | Array concatenation | Task
Show how to concatenate two arrays in your language.
If this is as simple as array1 + array2, so be it.
| #Simula | Simula | BEGIN ! Concatenate arrays - of REAL, here;
CLASS REAL_ARRAY(N); INTEGER N;
BEGIN
REAL ARRAY DATA(1:N);
! Return a new REAL_ARRAY containing
! the values from this REAL_ARRAY
! followed by the values from other;
REF(REAL_ARRAY) PROCEDURE CONCAT(other);
R... | Give a code snippet in #Simula
Task
Show how to concatenate two arrays in your language.
If this is as simple as array1 + array2, so be it.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Hello_world/Web_server | Hello world/Web server | The browser is the new GUI !
Task
Serve our standard text Goodbye, World! to http://localhost:8080/ so that it can be viewed with a web browser.
The provided solution must start or implement a server that accepts multiple client connections and serves text as requested.
Note that starting a web browser or... | #J | J | 'Goodbye, World!' | Give a code snippet in #J
The browser is the new GUI !
Task
Serve our standard text Goodbye, World! to http://localhost:8080/ so that it can be viewed with a web browser.
The provided solution must start or implement a server that accepts multiple client connections and serves text as requested.
Note tha... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Pell%27s_equation | Pell's equation | Pell's equation (also called the Pell–Fermat equation) is a Diophantine equation of the form:
x2 - ny2 = 1
with integer solutions for x and y, where n is a given non-square positive integer.
Task requirements
find the smallest solution in positive integers to Pell's equation for... | #Raku | Raku | use Lingua::EN::Numbers;
sub pell (Int $n) {
my $y = my $x = Int(sqrt $n);
my $z = 1;
my $r = 2 * $x;
my ($e1, $e2) = (1, 0);
my ($f1, $f2) = (0, 1);
loop {
$y = $r * $z - $y;
$z = Int(($n - $y²) / $z);
$r = Int(($x + $y) / $z);
($e1, $e2) = ($e2, $r * $... | Give a code snippet in #Raku
Pell's equation (also called the Pell–Fermat equation) is a Diophantine equation of the form:
x2 - ny2 = 1
with integer solutions for x and y, where n is a given non-square positive integer.
Task requirements
find the smallest solution in positive i... | christopher/rosetta-code | |
http://rosettacode.org/wiki/FTP | FTP | Task
Connect to a server, change directory, list its contents and download a file as binary using the FTP protocol. Use passive mode if available.
| #Scala | Scala | import java.io.{File, FileOutputStream, InputStream}
import org.apache.commons.net.ftp.{FTPClient, FTPFile, FTPReply}
import scala.util.{Failure, Try}
object FTPconn extends App {
val (server, pass) = ("ftp.ed.ac.uk", "-ftptest@example.com")
val (dir, filename, ftpClient) = ("/pub/cartonet/", "readme.txt", ne... | Give a code snippet in #Scala
Task
Connect to a server, change directory, list its contents and download a file as binary using the FTP protocol. Use passive mode if available.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Associative_array/Iteration | Associative array/Iteration | Show how to iterate over the key-value pairs of an associative array, and print each pair out.
Also show how to iterate just over the keys, or the values, if there is a separate way to do that in your language.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked ... | #Wart | Wart | h <- (table 'a 1 'b 2)
each (key val) table
prn key " " val | Give a code snippet in #Wart
Show how to iterate over the key-value pairs of an associative array, and print each pair out.
Also show how to iterate just over the keys, or the values, if there is a separate way to do that in your language.
See also
Array
Associative array: Creation, Iteration
Collections
Comp... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Bitmap/B%C3%A9zier_curves/Cubic | Bitmap/Bézier curves/Cubic | Using the data storage type defined on this page for raster images, and the draw_line function defined in this other one, draw a cubic bezier curve
(definition on Wikipedia).
| #Factor | Factor | USING: arrays kernel locals math math.functions
rosettacode.raster.storage sequences ;
IN: rosettacode.raster.line
! this gives a function
:: (cubic-bezier) ( P0 P1 P2 P3 -- bezier )
[ :> x
1 x - 3 ^ P0 n*v
1 x - sq 3 * x * P1 n*v
1 x - 3 * x sq * P2 n*v
x 3 ^ P3 n*v
v+ v+... | Give a code snippet in #Factor
Using the data storage type defined on this page for raster images, and the draw_line function defined in this other one, draw a cubic bezier curve
(definition on Wikipedia).
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Ordered_words | Ordered words | An ordered word is a word in which the letters appear in alphabetic order.
Examples include abbey and dirt.
Task[edit]
Find and display all the ordered words in the dictionary unixdict.txt that have the longest word length.
(Examples that access the dictionary file locally assume that you have download... | #Lasso | Lasso | local(f = file('unixdict.txt'), words = array, ordered = array, maxleng = 0)
#f->dowithclose => {
#f->foreachLine => {
#words->insert(#1)
}
}
with w in #words
do => {
local(tosort = #w->asString->values)
#tosort->sort
if(#w->asString == #tosort->join('')) => {
#ordered->insert(#w->asString)
#w->asString->siz... | Give a code snippet in #Lasso
An ordered word is a word in which the letters appear in alphabetic order.
Examples include abbey and dirt.
Task[edit]
Find and display all the ordered words in the dictionary unixdict.txt that have the longest word length.
(Examples that access the dictionary file locall... | christopher/rosetta-code | |
http://rosettacode.org/wiki/I_before_E_except_after_C | I before E except after C | The phrase "I before E, except after C" is a
widely known mnemonic which is supposed to help when spelling English words.
Task
Using the word list from http://wiki.puzzlers.org/pub/wordlists/unixdict.txt,
check if the two sub-clauses of the phrase are plausible individually:
"I before E when not pre... | #Mathematica_.2F_Wolfram_Language | Mathematica / Wolfram Language | wordlist =
Import["http://wiki.puzzlers.org/pub/wordlists/unixdict.txt",
"Words"];
Print["The number of words in unixdict.txt = " <>
ToString[Length[wordlist]]]
StringMatchQ[#, ___ ~~ "c" ~~ "i" ~~ "e" ~~ ___] & /@ wordlist ;
cie = Count[%, True];
StringMatchQ[#, ___ ~~ "c" ~~ "e" ~~ "i" ~~ ___] & /@ wordlist... | Give a code snippet in #Mathematica_.2F_Wolfram_Language
The phrase "I before E, except after C" is a
widely known mnemonic which is supposed to help when spelling English words.
Task
Using the word list from http://wiki.puzzlers.org/pub/wordlists/unixdict.txt,
check if the two sub-clauses of the phras... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Munchausen_numbers | Munchausen numbers | A Munchausen number is a natural number n the sum of whose digits (in base 10), each raised to the power of itself, equals n.
(Munchausen is also spelled: Münchhausen.)
For instance: 3435 = 33 + 44 + 33 + 55
Task
Find all Munchausen numbers between 1 and 5000.
Also see
The OEIS entry: A046253
The ... | #Plain_English | Plain English | To run:
Start up.
Show the Munchausen numbers up to 5000.
Wait for the escape key.
Shut down.
To show the Munchausen numbers up to a number:
If a counter is past the number, exit.
If the counter is Munchausen, convert the counter to a string; write the string to the console.
Repeat.
To decide if a number is Munchau... | Give a code snippet in #Plain_English
A Munchausen number is a natural number n the sum of whose digits (in base 10), each raised to the power of itself, equals n.
(Munchausen is also spelled: Münchhausen.)
For instance: 3435 = 33 + 44 + 33 + 55
Task
Find all Munchausen numbers between 1 and 5000.
Al... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Delete_a_file | Delete a file | Task
Delete a file called "input.txt" and delete a directory called "docs".
This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root.
| #HicEst | HicEst | SYSTEM(DIR="docs") ! create docs in current directory (if not existent), make it current
OPEN (FILE="input.txt", "NEW") ! in current directory = docs
WRITE(FIle="input.txt", DELETE=1) ! no command to DELETE a DIRECTORY in HicEst
SYSTEM(DIR="C:\docs") ! create C:\docs (if not existent), make it curren... | Give a code snippet in #HicEst
Task
Delete a file called "input.txt" and delete a directory called "docs".
This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Chowla_numbers | Chowla numbers | Chowla numbers are also known as:
Chowla's function
chowla numbers
the chowla function
the chowla number
the chowla sequence
The chowla number of n is (as defined by Chowla's function):
the sum of the divisors of n excluding unity and n
where n is a positive integer
The s... | #FreeBASIC | FreeBASIC |
' Chowla_numbers
#include "string.bi"
Dim Shared As Long limite
limite = 10000000
Dim Shared As Boolean c(limite)
Dim As Long count, topenumprimo, a
count = 1
topenumprimo = 100
Dim As Longint p, k, kk, limitenumperfect
limitenumperfect = 35000000
k = 2: kk = 3
Declare Function chowla(Byval n As Longint) As Lon... | Give a code snippet in #FreeBASIC
Chowla numbers are also known as:
Chowla's function
chowla numbers
the chowla function
the chowla number
the chowla sequence
The chowla number of n is (as defined by Chowla's function):
the sum of the divisors of n excluding unity and n
where ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Function_definition | Function definition | A function is a body of code that returns a value.
The value returned may depend on arguments provided to the function.
Task
Write a definition of a function called "multiply" that takes two arguments and returns their product.
(Argument types should be chosen so as not to distract from showing how functions are ... | #Gnuplot | Gnuplot | multiply(x,y) = x*y
# then for example
print multiply(123,456) | Give a code snippet in #Gnuplot
A function is a body of code that returns a value.
The value returned may depend on arguments provided to the function.
Task
Write a definition of a function called "multiply" that takes two arguments and returns their product.
(Argument types should be chosen so as not to distrac... | christopher/rosetta-code | |
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.
| #zkl | zkl | fcn sed(data,src,dst){
srcSz:=src.len(); dstSz:=dst.len(); md5:=Utils.MD5.calc(data);
n:=0; while(Void!=(n:=data.find(src,n)))
{ data.del(n,srcSz); data.insert(n,dst); n+= dstSz; }
return(md5!=Utils.MD5.calc(data)); // changed?
}
fcn sedFile(fname,src,dst){
f:=File(fname,"r"); data:=f.read(); f.c... | Give a code snippet in #zkl
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.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Last_letter-first_letter | Last letter-first letter | A certain children's game involves starting with a word in a particular category. Each participant in turn says a word, but that word must begin with the final letter of the previous word. Once a word has been given, it cannot be repeated. If an opponent cannot give a word in the category, they fall out of the ga... | #Perl | Perl | use strict;
my(%f,@m);
/^(.).*(.)$/,$f{$1}{$_}=$2 for qw(
audino bagon baltoy banette bidoof braviary bronzor carracosta charmeleon
cresselia croagunk darmanitan deino emboar emolga exeggcute gabite
girafarig gulpin haxorus heatmor heatran ivysaur jellicent jumpluff kangaskhan
kricketune landorus ledyba loudred lumin... | Give a code snippet in #Perl
A certain children's game involves starting with a word in a particular category. Each participant in turn says a word, but that word must begin with the final letter of the previous word. Once a word has been given, it cannot be repeated. If an opponent cannot give a word in the cat... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Abundant,_deficient_and_perfect_number_classifications | Abundant, deficient and perfect number classifications | These define three classifications of positive integers based on their proper divisors.
Let P(n) be the sum of the proper divisors of n where the proper divisors are all positive divisors of n other than n itself.
if P(n) < n then n is classed as deficient (OEIS A005100).
if P(n)... | #Kotlin | Kotlin | // version 1.1
fun sumProperDivisors(n: Int) =
if (n < 2) 0 else (1..n / 2).filter { (n % it) == 0 }.sum()
fun main(args: Array<String>) {
var sum: Int
var deficient = 0
var perfect = 0
var abundant = 0
for (n in 1..20000) {
sum = sumProperDivisors(n)
when {
sum... | Give a code snippet in #Kotlin
These define three classifications of positive integers based on their proper divisors.
Let P(n) be the sum of the proper divisors of n where the proper divisors are all positive divisors of n other than n itself.
if P(n) < n then n is classed as deficien... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Mad_Libs | Mad Libs |
This page uses content from Wikipedia. The original article was at Mad Libs. 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)
Mad Libs is a phrasal template word game where one player prompts another... | #C | C |
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define err(...) fprintf(stderr, ## __VA_ARGS__), exit(1)
/* We create a dynamic string with a few functions which make modifying
* the string and growing a bit easier */
typedef struct {
char *data;
size_t alloc;
size_t length;
} dstr;
inl... | Give a code snippet in #C
This page uses content from Wikipedia. The original article was at Mad Libs. 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)
Mad Libs is a phrasal template word game where... | christopher/rosetta-code | |
http://rosettacode.org/wiki/100_doors | 100 doors | There are 100 doors in a row that are all initially closed.
You make 100 passes by the doors.
The first time through, visit every door and toggle the door (if the door is closed, open it; if it is open, close it).
The second time, only visit every 2nd door (door #2, #4, #6, ...), and toggle it.
The third... | #FreeBASIC | FreeBASIC | ' version 27-10-2016
' compile with: fbc -s console
#Define max_doors 100
Dim As ULong c, n, n1, door(1 To max_doors)
' toggle, at start all doors are closed (0)
' 0 = door closed, 1 = door open
For n = 1 To max_doors
For n1 = n To max_doors Step n
door(n1) = 1 - door(n1)
Next
Next
' count the d... | Give a code snippet in #FreeBASIC
There are 100 doors in a row that are all initially closed.
You make 100 passes by the doors.
The first time through, visit every door and toggle the door (if the door is closed, open it; if it is open, close it).
The second time, only visit every 2nd door (door #2, #4, #6... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Chaos_game | Chaos game | The Chaos Game is a method of generating the attractor of an iterated function system (IFS).
One of the best-known and simplest examples creates a fractal, using a polygon and an initial point selected at random.
Task
Play the Chaos Game using the corners of an equilateral triangle as the reference points. Add a ... | #X86_Assembly | X86 Assembly | 1 ;Assemble with: tasm, tlink /t
2 0000 .model tiny
3 0000 .code
4 .386
5 org 100h
6 ... | Give a code snippet in #X86_Assembly
The Chaos Game is a method of generating the attractor of an iterated function system (IFS).
One of the best-known and simplest examples creates a fractal, using a polygon and an initial point selected at random.
Task
Play the Chaos Game using the corners of an equilateral tria... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sorting_algorithms/Bubble_sort | Sorting algorithms/Bubble sort |
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
... | #Tailspin | Tailspin |
templates bubblesort
templates bubble
@: 1;
1..$-1 -> #
$@ !
when <?($@bubblesort($+1) <..~$@bubblesort($)>)> do
@: $;
def temp: $@bubblesort($@);
@bubblesort($@): $@bubblesort($@+1);
@bubblesort($@+1): $temp;
end bubble
@: $;
$::length -> #
$@ !
when <2..> do
... | Give a code snippet in #Tailspin
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Strong_and_weak_primes | Strong and weak primes |
Definitions (as per number theory)
The prime(p) is the pth prime.
prime(1) is 2
prime(4) is 7
A strong prime is when prime(p) is > [prime(p-1) + prime(p+1)] ÷ 2
A weak prime is when prime(p) is < [prime(p-1) + prime(p+1)] ÷ 2
Note that the defin... | #Swift | Swift | import Foundation
class PrimeSieve {
var composite: [Bool]
init(size: Int) {
composite = Array(repeating: false, count: size/2)
var p = 3
while p * p <= size {
if !composite[p/2 - 1] {
let inc = p * 2
var q = p * p
while q <... | Give a code snippet in #Swift
Definitions (as per number theory)
The prime(p) is the pth prime.
prime(1) is 2
prime(4) is 7
A strong prime is when prime(p) is > [prime(p-1) + prime(p+1)] ÷ 2
A weak prime is when prime(p) is < [prime(p-1) + prime(... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Egyptian_fractions | Egyptian fractions | An Egyptian fraction is the sum of distinct unit fractions such as:
1
2
+
1
3
+
1
16
(
=
43
48
)
{\displaystyle {\tfrac {1}{2}}+{\tfrac {1}{3}}+{\tfrac {1}{16}}\,(={\tfrac {43}{48}})}
Each fraction in the expression has a numerator equal to 1 (unity) and a denominator that... | #Nim | Nim | import strformat, strutils
import bignum
let
Zero = newInt(0)
One = newInt(1)
#---------------------------------------------------------------------------------------------------
proc toEgyptianrecursive(rat: Rat; fracs: seq[Rat]): seq[Rat] =
if rat.isZero: return fracs
let iquo = cdiv(rat.denom, rat.... | Give a code snippet in #Nim
An Egyptian fraction is the sum of distinct unit fractions such as:
1
2
+
1
3
+
1
16
(
=
43
48
)
{\displaystyle {\tfrac {1}{2}}+{\tfrac {1}{3}}+{\tfrac {1}{16}}\,(={\tfrac {43}{48}})}
Each fraction in the expression has a numerator equal to 1 (un... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Unicode_strings | Unicode strings | As the world gets smaller each day, internationalization becomes more and more important. For handling multiple languages, Unicode is your best friend.
It is a very capable tool, but also quite complex compared to older single- and double-byte character encodings.
How well prepared is your programming language for ... | #8th | 8th | #!/usr/local/bin/a68g --script #
# -*- coding: utf-8 -*- #
# UNICHAR/UNICODE must be printed using REPR to convert to UTF8 #
MODE UNICHAR = STRUCT(BITS #31# bits); # assuming bits width >=31 #
MODE UNICODE = FLEX[0]UNICHAR;
OP INITUNICHAR = (BITS bits)UNICHAR: (UNICHAR out; bits OF out := #ABS# bits; out);
OP INI... | Give a code snippet in #8th
As the world gets smaller each day, internationalization becomes more and more important. For handling multiple languages, Unicode is your best friend.
It is a very capable tool, but also quite complex compared to older single- and double-byte character encodings.
How well prepared is y... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Keyboard_input/Keypress_check | Keyboard input/Keypress check |
Determine if a key has been pressed and store this in a variable.
If no key has been pressed, the program should continue without waiting.
| #JavaScript | JavaScript |
let thePressedKey;
function handleKey(evt) {
thePressedKey = evt;
console.log(thePressedKey);
}
document.addEventListener('keydown', handleKey);
| Give a code snippet in #JavaScript
Determine if a key has been pressed and store this in a variable.
If no key has been pressed, the program should continue without waiting.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Text_processing/Max_licenses_in_use | Text processing/Max licenses in use | A company currently pays a fixed sum for the use of a particular licensed software package. In determining if it has a good deal it decides to calculate its maximum use of the software from its license management log file.
Assume the software's licensing daemon faithfully records a checkout event when a copy of the ... | #Fortran | Fortran |
PROGRAM MAX_LICENSES
IMPLICIT NONE
INTEGER :: out=0, maxout=0, maxcount=0, err
CHARACTER(50) :: line
CHARACTER(19) :: maxtime(100)
OPEN (UNIT=5, FILE="Licenses.txt", STATUS="OLD", IOSTAT=err)
IF (err > 0) THEN
WRITE(*,*) "Error opening file Licenses.txt"
STOP
END IF
DO
R... | Give a code snippet in #Fortran
A company currently pays a fixed sum for the use of a particular licensed software package. In determining if it has a good deal it decides to calculate its maximum use of the software from its license management log file.
Assume the software's licensing daemon faithfully records a c... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Associative_array/Creation | Associative array/Creation | Task
The goal is to create an associative array (also known as a dictionary, map, or hash).
Related tasks:
Associative arrays/Iteration
Hash from two arrays
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element ins... | #LFE | LFE |
(let* ((my-dict (: dict new))
(my-dict (: dict store 'key-1 '"value 1" my-dict))
(my-dict (: dict store 'key-2 '"value 2" my-dict)))
(: io format '"size: ~p~n" (list (: dict size my-dict)))
(: io format '"some data: ~p~n" (list (: dict fetch 'key-1 my-dict))))
| Give a code snippet in #LFE
Task
The goal is to create an associative array (also known as a dictionary, map, or hash).
Related tasks:
Associative arrays/Iteration
Hash from two arrays
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, El... | christopher/rosetta-code | |
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))) | Give a code snippet in #Common_Lisp
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... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Josephus_problem | Josephus problem | Josephus problem is a math puzzle with a grim description:
n
{\displaystyle n}
prisoners are standing on a circle, sequentially numbered from
0
{\displaystyle 0}
to
n
−
1
{\displaystyle n-1}
.
An executioner walks along the circle, starting from prisoner
0
{\displaystyle 0}
,
removing eve... | #Processing | Processing | void setup() {
println("Survivor: " + execute(41, 3));
println("Survivors: " + executeAllButM(41, 3, 3));
}
int execute(int n, int k) {
int killIdx = 0;
IntList prisoners = new IntList(n);
for (int i = 0; i < n; i++) {
prisoners.append(i);
}
println("Prisoners executed in order:");
while (prisoner... | Give a code snippet in #Processing
Josephus problem is a math puzzle with a grim description:
n
{\displaystyle n}
prisoners are standing on a circle, sequentially numbered from
0
{\displaystyle 0}
to
n
−
1
{\displaystyle n-1}
.
An executioner walks along the circle, starting from prisoner
0... | christopher/rosetta-code | |
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... | #Action.21 | Action! | BYTE FUNC SumOfSquares(BYTE x)
BYTE sum,d
sum=0
WHILE x#0
DO
d=x MOD 10
d==*d
sum==+d
x==/10
OD
RETURN (sum)
BYTE FUNC Contains(BYTE ARRAY a BYTE count,x)
BYTE i
FOR i=0 TO count-1
DO
IF a(i)=x THEN RETURN (1) FI
OD
RETURN (0)
BYTE FUNC IsHappyNumber(BYTE x)
BYTE ARRAY ca... | Give a code snippet in #Action.21
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 endles... | christopher/rosetta-code | |
http://rosettacode.org/wiki/File_size | File size | Verify the size of a file called input.txt for a file in the current working directory, and another one in the file system root.
| #Euphoria | Euphoria | include file.e
function file_size(sequence file_name)
object x
x = dir(file_name)
if sequence(x) and length(x) = 1 then
return x[1][D_SIZE]
else
return -1 -- the file does not exist
end if
end function
procedure test(sequence file_name)
integer size
size = file_size(file_... | Give a code snippet in #Euphoria
Verify the size of a file called input.txt for a file in the current working directory, and another one in the file system root.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Exceptions | Exceptions | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
This task is to give an example of an exception handling routine
and to "throw" a new exception.
Related task
Exceptions Through Nested Calls
| #JavaScript | JavaScript | function doStuff() {
throw new Error('Not implemented!');
} | Give a code snippet in #JavaScript
Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
This task is to give an example of an exception handling routine
and to "throw" a new exception.
Related task
Excep... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Horizontal_sundial_calculations | Horizontal sundial calculations | Task
Create a program that calculates the hour, sun hour angle, dial hour line angle from 6am to 6pm for an operator entered location.
For example, the user is prompted for a location and inputs the latitude and longitude 4°57′S 150°30′W (4.95°S 150.5°W of Jules Verne's Lincoln Island, aka Ernest Legouve Reef), wit... | #XPL0 | XPL0 | inc c:\cxpl\codes;
def Pi = 3.14159265358979323846,
Deg2Rad = Pi/180.0,
Rad2Deg = 180.0/Pi,
Tab = $09;
real Lat, SinLat, Long, Mer;
real HA, HLA; \hour angle and hour line angle
int H, T; \hour, time
[Text(0, "Latitude: "); Lat:= RlIn(0);
Text(0, "Longit... | Give a code snippet in #XPL0
Task
Create a program that calculates the hour, sun hour angle, dial hour line angle from 6am to 6pm for an operator entered location.
For example, the user is prompted for a location and inputs the latitude and longitude 4°57′S 150°30′W (4.95°S 150.5°W of Jules Verne's Lincoln Island,... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Pick_random_element | Pick random element | Demonstrate how to pick a random element from a list.
| #UNIX_Shell | UNIX Shell | list=(these are some words)
printf '%s\n' "${list[RANDOM%${#list[@]}]}" | Give a code snippet in #UNIX_Shell
Demonstrate how to pick a random element from a list.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Population_count | Population count | Population count
You are encouraged to solve this task according to the task description, using any language you may know.
The population count is the number of 1s (ones) in the binary representation of a non-negative integer.
Population count is also known as:
pop count
popcount
sideways sum
... | #Tcl | Tcl | package require Tcl 8.6
proc hammingWeight {n} {
tcl::mathop::+ {*}[split [format %llb $n] ""]
}
for {set n 0;set l {}} {$n<30} {incr n} {
lappend l [hammingWeight [expr {3**$n}]]
}
puts "p3: $l"
for {set n 0;set e [set o {}]} {[llength $e]<30||[llength $o]<30} {incr n} {
lappend [expr {[hammingWeight $n]... | Give a code snippet in #Tcl
Population count
You are encouraged to solve this task according to the task description, using any language you may know.
The population count is the number of 1s (ones) in the binary representation of a non-negative integer.
Population count is also known as:
pop count
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Read_entire_file | Read entire file | Task
Load the entire contents of some text file as a single string variable.
If applicable, discuss: encoding selection, the possibility of memory-mapping.
Of course, in practice one should avoid reading an entire file at once
if the file is large and the task can be accomplished incrementally instead
(in which case... | #Euphoria | Euphoria |
function load_file(sequence filename)
integer fn,c
sequence data
fn = open(filename,"r") -- "r" for text files, "rb" for binary files
if (fn = -1) then return {} end if -- failed to open the file
data = {} -- init to empty sequence
c = getc(fn) -- prime the char buffer
while (c != -1) do -- ... | Give a code snippet in #Euphoria
Task
Load the entire contents of some text file as a single string variable.
If applicable, discuss: encoding selection, the possibility of memory-mapping.
Of course, in practice one should avoid reading an entire file at once
if the file is large and the task can be accomplished in... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Monty_Hall_problem | Monty Hall problem |
Suppose you're on a game show and you're given the choice of three doors.
Behind one door is a car; behind the others, goats.
The car and the goats were placed randomly behind the doors before the show.
Rules of the game
After you have chosen a door, the door remains closed for the time being.
The game show hos... | #PureBasic | PureBasic | Structure wins
stay.i
redecide.i
EndStructure
#goat = 0
#car = 1
Procedure MontyHall(*results.wins)
Dim Doors(2)
Doors(Random(2)) = #car
player = Random(2)
Select Doors(player)
Case #car
*results\redecide + #goat
*results\stay + #car
Case #goat
*results\redecide + #car
*r... | Give a code snippet in #PureBasic
Suppose you're on a game show and you're given the choice of three doors.
Behind one door is a car; behind the others, goats.
The car and the goats were placed randomly behind the doors before the show.
Rules of the game
After you have chosen a door, the door remains closed for... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Matrix_transposition | Matrix transposition | Transpose an arbitrarily sized rectangular Matrix.
| #Agda | Agda | module Matrix where
open import Data.Nat
open import Data.Vec
Matrix : (A : Set) → ℕ → ℕ → Set
Matrix A m n = Vec (Vec A m) n
transpose : ∀ {A m n} → Matrix A m n → Matrix A n m
transpose [] = replicate []
transpose (xs ∷ xss) = zipWith _∷_ xs (transpose xss)
a = (1 ∷ 2 ∷ 3 ∷ []) ∷ (4 ∷ 5 ∷ 6 ∷ []) ∷ []
b = tra... | Give a code snippet in #Agda
Transpose an arbitrarily sized rectangular Matrix.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Arithmetic_evaluation | Arithmetic evaluation | Create a program which parses and evaluates arithmetic expressions.
Requirements
An abstract-syntax tree (AST) for the expression must be created from parsing the input.
The AST must be used in evaluation, also, so the input may not be directly evaluated (e.g. by calling eval or a similar language feature.)
The ... | #Scheme | Scheme |
(import (scheme base)
(scheme char)
(scheme cxr)
(scheme write)
(srfi 1 lists))
;; convert a string into a list of tokens
(define (string->tokens str)
(define (next-token chars)
(cond ((member (car chars) (list #\+ #\- #\* #\/) char=?)
(values (cdr chars)
... | Give a code snippet in #Scheme
Create a program which parses and evaluates arithmetic expressions.
Requirements
An abstract-syntax tree (AST) for the expression must be created from parsing the input.
The AST must be used in evaluation, also, so the input may not be directly evaluated (e.g. by calling eval or a s... | christopher/rosetta-code | |
http://rosettacode.org/wiki/File_size | File size | Verify the size of a file called input.txt for a file in the current working directory, and another one in the file system root.
| #ALGOL_68 | ALGOL 68 | PROC set = (REF FILE file, INT page, line, character)VOID: ~ | Give a code snippet in #ALGOL_68
Verify the size of a file called input.txt for a file in the current working directory, and another one in the file system root.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Create_a_file | Create a file | In this task, the job is to create a new empty file called "output.txt" of size 0 bytes
and an empty directory called "docs". This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root.
| #Visual_Basic_.NET | Visual Basic .NET | 'Current Directory
IO.Directory.CreateDirectory("docs")
IO.File.Create("output.txt").Close()
'Root
IO.Directory.CreateDirectory("\docs")
IO.File.Create("\output.txt").Close()
'Root, platform independent
IO.Directory.CreateDirectory(IO.Path.DirectorySeparatorChar & "docs")
IO.File.Create(IO.Path.DirectorySeparato... | Give a code snippet in #Visual_Basic_.NET
In this task, the job is to create a new empty file called "output.txt" of size 0 bytes
and an empty directory called "docs". This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Dot_product | Dot product | Task
Create a function/use an in-built function, to compute the dot product, also known as the scalar product of two vectors.
If possible, make the vectors of arbitrary length.
As an example, compute the dot product of the vectors:
[1, 3, -5] and
[4, -2, -1]
If implementing the dot ... | #F.23 | F# | let dot_product (a:array<'a>) (b:array<'a>) =
if Array.length a <> Array.length b then failwith "invalid argument: vectors must have the same lengths"
Array.fold2 (fun acc i j -> acc + (i * j)) 0 a b | Give a code snippet in #F.23
Task
Create a function/use an in-built function, to compute the dot product, also known as the scalar product of two vectors.
If possible, make the vectors of arbitrary length.
As an example, compute the dot product of the vectors:
[1, 3, -5] and
[4, -2, -1]... | christopher/rosetta-code | |
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
... | #Casio_BASIC | Casio BASIC | (* FizzBuzz in CDuce *)
let format (n : Int) : Latin1 =
if (n mod 3 = 0) || (n mod 5 = 0) then "FizzBuzz"
else if (n mod 5 = 0) then "Buzz"
else if (n mod 3 = 0) then "Fizz"
else string_of (n);;
let fizz (n : Int, size : Int) : _ =
print (format (n) @ "\n");
if (n = size) then
n = 0... | Give a code snippet in #Casio_BASIC
Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print Fi... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Lucas-Lehmer_test | Lucas-Lehmer test | Lucas-Lehmer Test:
for
p
{\displaystyle p}
an odd prime, the Mersenne number
2
p
−
1
{\displaystyle 2^{p}-1}
is prime if and only if
2
p
−
1
{\displaystyle 2^{p}-1}
divides
S
(
p
−
1
)
{\displaystyle S(p-1)}
where
S
(
n
+
1
)
=
(
S
(
n
)
)
2
−
2
{\displaystyle S(n+1)=(... | #HicEst | HicEst | s = 0
DO exponent = 2, 31
IF(exponent > 2) s = 4
n = 2^exponent - 1
DO i = 1, exponent-2
s = MOD(s*s - 2, n)
ENDDO
IF(s == 0) WRITE(Messagebox) 'M', exponent, ' is prime;', n
ENDDO
END | Give a code snippet in #HicEst
Lucas-Lehmer Test:
for
p
{\displaystyle p}
an odd prime, the Mersenne number
2
p
−
1
{\displaystyle 2^{p}-1}
is prime if and only if
2
p
−
1
{\displaystyle 2^{p}-1}
divides
S
(
p
−
1
)
{\displaystyle S(p-1)}
where
S
(
n
+
1
)
=
(
S
(
n
)
)
2... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Left_factorials | Left factorials | Left factorials, !n, may refer to either subfactorials or to factorial sums;
the same notation can be confusingly seen being used for the two different definitions.
Sometimes, subfactorials (also known as derangements) may use any of the notations:
!n`
!n
n¡
(It may not be vis... | #Nim | Nim | import iterutils, bigints
proc lfact: iterator: BigInt =
result = iterator: BigInt =
yield 0.initBigInt
var
fact = 1.initBigInt
sum = 0.initBigInt
n = 1.initBigInt
while true:
sum += fact
fact *= n
n += 1
yield sum
echo "first 11:\n "
for i in lfact().slice(l... | Give a code snippet in #Nim
Left factorials, !n, may refer to either subfactorials or to factorial sums;
the same notation can be confusingly seen being used for the two different definitions.
Sometimes, subfactorials (also known as derangements) may use any of the notations:
!n`
!n
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Musical_scale | Musical scale | Task
Output the 8 notes of the C major diatonic scale to the default musical sound device on the system. Specifically, pitch must be tuned to 12-tone equal temperament (12TET) with the modern standard A=440Hz.
These are the notes "C, D, E, F, G, A, B, C(1 octave higher)", or "Do, Re, Mi, Fa, Sol, La, Si/Ti, Do(1 octa... | #Ursa | Ursa | decl double<> notes
append 261.63 293.66 329.63 349.23 392.00 440.00 493.88 523.25 notes
for (decl int i) (< i (size notes)) (inc i)
ursa.util.sound.beep notes<i> 0.5
end for | Give a code snippet in #Ursa
Task
Output the 8 notes of the C major diatonic scale to the default musical sound device on the system. Specifically, pitch must be tuned to 12-tone equal temperament (12TET) with the modern standard A=440Hz.
These are the notes "C, D, E, F, G, A, B, C(1 octave higher)", or "Do, Re, Mi,... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Unicode_variable_names | Unicode variable names | Task
Describe, and give a pointer to documentation on your languages use of characters beyond those of the ASCII character set in the naming of variables.
Show how to:
Set a variable with a name including the 'Δ', (delta character), to 1
Increment it
Print its value.
Related task
Case-sensitivity of identif... | #Clojure | Clojure | (let [Δ 1]
(inc Δ)) | Give a code snippet in #Clojure
Task
Describe, and give a pointer to documentation on your languages use of characters beyond those of the ASCII character set in the naming of variables.
Show how to:
Set a variable with a name including the 'Δ', (delta character), to 1
Increment it
Print its value.
Related ta... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Arithmetic/Rational | Arithmetic/Rational | Task
Create a reasonably complete implementation of rational arithmetic in the particular language using the idioms of the language.
Example
Define a new type called frac with binary operator "//" of two integers that returns a structure made up of the numerator and the denominator (as per a rational number).
Fur... | #Modula-3 | Modula-3 | INTERFACE Frac;
EXCEPTION ZeroDenominator;
TYPE
T <: Public;
Public = OBJECT
METHODS
(* initialization and conversion *)
init(a, b: INTEGER): T RAISES { ZeroDenominator };
fromInt(a: INTEGER): T;
(* unary operators *)
abs(): T;
opposite(): T;
(* binary operators *)
plus(other... | Give a code snippet in #Modula-3
Task
Create a reasonably complete implementation of rational arithmetic in the particular language using the idioms of the language.
Example
Define a new type called frac with binary operator "//" of two integers that returns a structure made up of the numerator and the denominato... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sum_and_product_of_an_array | Sum and product of an array | Task
Compute the sum and product of an array of integers.
| #VBScript | VBScript | Function sum_and_product(arr)
sum = 0
product = 1
For i = 0 To UBound(arr)
sum = sum + arr(i)
product = product * arr(i)
Next
WScript.StdOut.Write "Sum: " & sum
WScript.StdOut.WriteLine
WScript.StdOut.Write "Product: " & product
WScript.StdOut.WriteLine
End Function
myarray = Array(1,2,3,4,5,6)
sum_and_pr... | Give a code snippet in #VBScript
Task
Compute the sum and product of an array of integers.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Null_object | Null object |
Null (or nil) is the computer science concept of an undefined or unbound object.
Some languages have an explicit way to access the null object, and some don't.
Some languages distinguish the null object from undefined values, and some don't.
Task
Show how to access null in your language by checking to see if an ob... | #Objective-C | Objective-C | // here "object" is an object pointer
if (object == nil) {
NSLog("object is nil");
} | Give a code snippet in #Objective-C
Null (or nil) is the computer science concept of an undefined or unbound object.
Some languages have an explicit way to access the null object, and some don't.
Some languages distinguish the null object from undefined values, and some don't.
Task
Show how to access null in your... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as t... | #Lambdatalk | Lambdatalk |
{def allsame
{def allsame.r
{lambda {:s :n :i}
{if {= :i :n}
then true
else {if {not {W.equal? {A.get :i :s} {A.get 0 :s}}}
then false
else {allsame.r :s :n {+ :i 1}} }}}}
{lambda {:s}
{allsame.r :s {- {A.length :s} 1} 0} }}
-> allsame
{def strict_order
{def strict_order.r
{lambda {:s :n... | Give a code snippet in #Lambdatalk
Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or f... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Truncatable_primes | Truncatable primes | A truncatable prime is a prime number that when you successively remove digits from one end of the prime, you are left with a new prime number.
Examples
The number 997 is called a left-truncatable prime as the numbers 997, 97, and 7 are all prime.
The number 7393 is a right-truncatable prime as the numbers 7393, 7... | #CoffeeScript | CoffeeScript | # You could have symmetric algorithms for max right and left
# truncatable numbers, but they lend themselves to slightly
# different optimizations.
max_right_truncatable_number = (n, f) ->
# This algorithm only evaluates 37 numbers for primeness to
# get the max right truncatable prime < 1000000. Its
# optimiz... | Give a code snippet in #CoffeeScript
A truncatable prime is a prime number that when you successively remove digits from one end of the prime, you are left with a new prime number.
Examples
The number 997 is called a left-truncatable prime as the numbers 997, 97, and 7 are all prime.
The number 7393 is a right-tr... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Simple_windowed_application | Simple windowed application | Task
Create a window that has:
a label that says "There have been no clicks yet"
a button that says "click me"
Upon clicking the button with the mouse, the label should change and show the number of times the button has been clicked.
| #Web_68 | Web 68 | @1Introduction.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public Licence as published by
the Free Software Foundation, either version 3 of the Licence, or
(at your option) any later version.
Copyright (c) 2012 Sian Mountbatten.
@m cvs simpleapp = "$Id... | Give a code snippet in #Web_68
Task
Create a window that has:
a label that says "There have been no clicks yet"
a button that says "click me"
Upon clicking the button with the mouse, the label should change and show the number of times the button has been clicked.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Runtime_evaluation | Runtime evaluation | Task
Demonstrate a language's ability for programs to execute code written in the language provided at runtime.
Show what kind of program fragments are permitted (e.g. expressions vs. statements), and how to get values in and out (e.g. environments, arguments, return values), if applicable what lexical/static environ... | #UNIX_Shell | UNIX Shell | $ a=42
$ b=a
$ eval "echo \$$b"
42 | Give a code snippet in #UNIX_Shell
Task
Demonstrate a language's ability for programs to execute code written in the language provided at runtime.
Show what kind of program fragments are permitted (e.g. expressions vs. statements), and how to get values in and out (e.g. environments, arguments, return values), if ap... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Strip_whitespace_from_a_string/Top_and_tail | Strip whitespace from a string/Top and tail | Task
Demonstrate how to strip leading and trailing whitespace from a string.
The solution should demonstrate how to achieve the following three results:
String with leading whitespace removed
String with trailing whitespace removed
String with both leading and trailing whitespace removed
For the purposes of thi... | #Lasso | Lasso | // String with leading whitespace removed
'>' + (' \t Hello')->trim& + '<'
// String with trailing whitespace removed
'>' + ('Hello \t ')->trim& + '<'
// String with both leading and trailing whitespace removed
'>' + (' \t Hello \t ')->trim& + '<' | Give a code snippet in #Lasso
Task
Demonstrate how to strip leading and trailing whitespace from a string.
The solution should demonstrate how to achieve the following three results:
String with leading whitespace removed
String with trailing whitespace removed
String with both leading and trailing whitespace re... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Padovan_n-step_number_sequences | Padovan n-step number sequences | As the Fibonacci sequence expands to the Fibonacci n-step number sequences; We similarly expand the Padovan sequence to form these Padovan n-step number sequences.
The Fibonacci-like sequences can be defined like this:
For n == 2:
start: 1, 1
Recurrence: R(n, x) = R(n, x-1) + R(n, x-2); for n ==... | #ALGOL_W | ALGOL W | begin % show some valuies of the Padovan n-step number sequences %
% sets R(i,j) to the jth element of the ith padovan sequence %
% maxS is the number of sequences to generate and maxE is the %
% maximum number of elements for each sequence %
% maxS must be >= 2 ... | Give a code snippet in #ALGOL_W
As the Fibonacci sequence expands to the Fibonacci n-step number sequences; We similarly expand the Padovan sequence to form these Padovan n-step number sequences.
The Fibonacci-like sequences can be defined like this:
For n == 2:
start: 1, 1
Recurrence: R(n, x) ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Repeat | Repeat | Task
Write a procedure which accepts as arguments another procedure and a positive integer.
The latter procedure is executed a number of times equal to the accepted integer.
| #Scala | Scala | def repeat[A](n:Int)(f: => A)= ( 0 until n).foreach(_ => f)
repeat(3) { println("Example") } | Give a code snippet in #Scala
Task
Write a procedure which accepts as arguments another procedure and a positive integer.
The latter procedure is executed a number of times equal to the accepted integer.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Set_puzzle | Set puzzle | Set Puzzles are created with a deck of cards from the Set Game™. The object of the puzzle is to find sets of 3 cards in a rectangle of cards that have been dealt face up.
There are 81 cards in a deck.
Each card contains a unique variation of the following four features: color, symbol, number and shading.
there are... | #Haskell | Haskell | import Control.Monad.State
(State, evalState, replicateM, runState, state)
import System.Random (StdGen, newStdGen, randomR)
import Data.List (find, nub, sort)
combinations :: Int -> [a] -> [[a]]
combinations 0 _ = [[]]
combinations _ [] = []
combinations k (y:ys) = map (y :) (combinations (k - 1) ys) ++ combi... | Give a code snippet in #Haskell
Set Puzzles are created with a deck of cards from the Set Game™. The object of the puzzle is to find sets of 3 cards in a rectangle of cards that have been dealt face up.
There are 81 cards in a deck.
Each card contains a unique variation of the following four features: color, symbol... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Look-and-say_sequence | Look-and-say sequence | The Look and say sequence is a recursively defined sequence of numbers studied most notably by John Conway.
The look-and-say sequence is also known as the Morris Number Sequence, after cryptographer Robert Morris, and the puzzle What is the next number in the sequence 1, 11, 21, 1211, 11122... | #J | J | las=: ,@((# , {.);.1~ 1 , 2 ~:/\ ])&.(10x&#.inv)@]^:(1+i.@[) | Give a code snippet in #J
The Look and say sequence is a recursively defined sequence of numbers studied most notably by John Conway.
The look-and-say sequence is also known as the Morris Number Sequence, after cryptographer Robert Morris, and the puzzle What is the next number in the sequence 1, ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Read_a_file_line_by_line | Read a file line by line | Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
| #Run_BASIC | Run BASIC | open DefaultDir$ + "\public\filetest.txt" for input as #f
while not(eof(#f))
line input #f, a$
print a$
wend
close #f
| Give a code snippet in #Run_BASIC
Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Emacs_Lisp | Emacs Lisp | ; This is a comment | Give a code snippet in #Emacs_Lisp
Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| christopher/rosetta-code | |
http://rosettacode.org/wiki/String_length | String length | Task
Find the character and byte length of a string.
This means encodings like UTF-8 need to be handled properly, as there is not necessarily a one-to-one relationship between bytes and characters.
By character, we mean an individual Unicode code point, not a user-visible grapheme containing combining characters.
F... | #Potion | Potion | "møøse" length print
"𝔘𝔫𝔦𝔠𝔬𝔡𝔢" length print
"J̲o̲s̲é̲" length print | Give a code snippet in #Potion
Task
Find the character and byte length of a string.
This means encodings like UTF-8 need to be handled properly, as there is not necessarily a one-to-one relationship between bytes and characters.
By character, we mean an individual Unicode code point, not a user-visible grapheme con... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Cheryl%27s_birthday | Cheryl's birthday | Albert and Bernard just became friends with Cheryl, and they want to know when her birthday is.
Cheryl gave them a list of ten possible dates:
May 15, May 16, May 19
June 17, June 18
July 14, July 16
August 14, August 15, August 17
Cheryl then tells Albert the month of birth, ... | #Kotlin | Kotlin | // Version 1.2.71
val months = listOf(
"January", "February", "March", "April", "May", "June",
"July", "August", "September", "October", "November", "December"
)
class Birthday(val month: Int, val day: Int) {
public override fun toString() = "${months[month - 1]} $day"
public fun monthUniqueIn(bds... | Give a code snippet in #Kotlin
Albert and Bernard just became friends with Cheryl, and they want to know when her birthday is.
Cheryl gave them a list of ten possible dates:
May 15, May 16, May 19
June 17, June 18
July 14, July 16
August 14, August 15, August 17
Cheryl then tells... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Higher-order_functions | Higher-order functions | Task
Pass a function as an argument to another function.
Related task
First-class functions
| #Visual_Basic_.NET | Visual Basic .NET | f=Add, f(6, 2) = 8
f=Mul, f(6, 2) = 12
f=Div, f(6, 2) = 3 | Give a code snippet in #Visual_Basic_.NET
Task
Pass a function as an argument to another function.
Related task
First-class functions
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Digital_root/Multiplicative_digital_root | Digital root/Multiplicative digital root | The multiplicative digital root (MDR) and multiplicative persistence (MP) of a number,
n
{\displaystyle n}
, is calculated rather like the Digital root except digits are multiplied instead of being added:
Set
m
{\displaystyle m}
to
n
{\displaystyle n}
and
i
{\displaystyle i}
to
0
... | #CLU | CLU | digits = iter (n: int) yields (int)
while n>0 do
yield(n//10)
n := n/10
end
end digits
mdr = proc (n: int) returns (int,int)
i: int := 0
while n>=10 do
m: int := 1
for d: int in digits(n) do
m := m * d
end
n := m
i := i+1
end
... | Give a code snippet in #CLU
The multiplicative digital root (MDR) and multiplicative persistence (MP) of a number,
n
{\displaystyle n}
, is calculated rather like the Digital root except digits are multiplied instead of being added:
Set
m
{\displaystyle m}
to
n
{\displaystyle n}
and
i
{\... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Anonymous_recursion | Anonymous recursion | While implementing a recursive function, it often happens that we must resort to a separate helper function to handle the actual recursion.
This is usually the case when directly calling the current function would waste too many resources (stack space, execution time), causing unwanted side-effects, and/or the f... | #IS-BASIC | IS-BASIC | 100 PROGRAM "Fibonacc.bas"
110 FOR I=0 TO 10
120 PRINT FIB(I);
130 NEXT
140 DEF FIB(K)
150 SELECT CASE K
160 CASE IS<0
170 PRINT "Negative parameter to Fibonacci.":STOP
180 CASE 0
190 LET FIB=0
200 CASE 1
210 LET FIB=1
220 CASE ELSE
230 LET FIB=FIB(K-1)+FIB(K-2)
240 END SELECT
250 END DE... | Give a code snippet in #IS-BASIC
While implementing a recursive function, it often happens that we must resort to a separate helper function to handle the actual recursion.
This is usually the case when directly calling the current function would waste too many resources (stack space, execution time), causing unw... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sequence_of_non-squares | Sequence of non-squares | Task
Show that the following remarkable formula gives the sequence of non-square natural numbers:
n + floor(1/2 + sqrt(n))
Print out the values for n in the range 1 to 22
Show that no squares occur for n less than one million
This is sequence A000037 in the OEIS database.
| #FreeBASIC | FreeBASIC | ' FB 1.05.0 Win64
Function nonSquare (n As UInteger) As UInteger
Return CUInt(n + Int(0.5 + Sqr(n)))
End Function
Function isSquare (n As UInteger) As Boolean
Dim As UInteger r = CUInt(Sqr(n))
Return n = r * r
End Function
Print "The first 22 numbers generated by the sequence are :"
For i As Integer = 1 To ... | Give a code snippet in #FreeBASIC
Task
Show that the following remarkable formula gives the sequence of non-square natural numbers:
n + floor(1/2 + sqrt(n))
Print out the values for n in the range 1 to 22
Show that no squares occur for n less than one million
This is sequence A0... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Pointers_and_references | Pointers and references |
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
Concatenation |
Interpolation |... | #E | E | var x := 0
def slot := &x # define "slot" to be x's slot
x := 1 # direct assignment; value is now 1
slot.put(2) # via slot object; value is now 2
| Give a code snippet in #E
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
Conc... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Leap_year | Leap year | Task
Determine whether a given year is a leap year in the Gregorian calendar.
See also
Leap year (wiki)
| #Racket | Racket | (define (leap-year? y)
(and (zero? (modulo y 4)) (or (positive? (modulo y 100)) (zero? (modulo y 400))))) | Give a code snippet in #Racket
Task
Determine whether a given year is a leap year in the Gregorian calendar.
See also
Leap year (wiki)
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Variables | Variables | Task
Demonstrate a language's methods of:
variable declaration
initialization
assignment
datatypes
scope
referencing, and
other variable related facilities
| #Oforth | Oforth | import: date
: testVariable
| a b c |
Date now ->a
a println ; | Give a code snippet in #Oforth
Task
Demonstrate a language's methods of:
variable declaration
initialization
assignment
datatypes
scope
referencing, and
other variable related facilities
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Nth_root | Nth root | Task
Implement the algorithm to compute the principal nth root
A
n
{\displaystyle {\sqrt[{n}]{A}}}
of a positive real number A, as explained at the Wikipedia page.
| #NewLISP | NewLISP | (define (nth-root n a)
(let ((x1 a)
(x2 (div a n)))
(until (= x1 x2)
(setq x1 x2
x2 (div
(add
(mul x1 (- n 1))
(div a (pow x1 (- n 1))))
n)))
x2)) | Give a code snippet in #NewLISP
Task
Implement the algorithm to compute the principal nth root
A
n
{\displaystyle {\sqrt[{n}]{A}}}
of a positive real number A, as explained at the Wikipedia page.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Draw_a_pixel | Draw a pixel | Task
Create a window and draw a pixel in it, subject to the following:
the window is 320 x 240
the color of the pixel must be red (255,0,0)
the position of the pixel is x = 100, y = 100 | #Processing | Processing | size(320, 240);
set(100, 100, color(255,0,0)); | Give a code snippet in #Processing
Task
Create a window and draw a pixel in it, subject to the following:
the window is 320 x 240
the color of the pixel must be red (255,0,0)
the position of the pixel is x = 100, y = 100 | christopher/rosetta-code | |
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... | #Lasso | Lasso | #!/usr/bin/lasso9
local(
lower = integer_random(10, 1),
higher = integer_random(100, 20),
number = integer_random(#higher, #lower),
status = false,
guess
)
// prompt for a number
stdout('Guess a number: ')
while(not #status) => {
#guess = null
// the following bits wait until the terminal gives you back ... | Give a code snippet in #Lasso
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:
hi... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Literals/Integer | Literals/Integer | Some programming languages have ways of expressing integer literals in bases other than the normal base ten.
Task
Show how integer literals can be expressed in as many bases as your language allows.
Note: this should not involve the calling of any functions/methods, but should be interpreted by the compiler or... | #REXX | REXX | /*REXX pgm displays an integer (expressed in the pgm as a literal) in different bases*/
/*────────── expressing decimal numbers ──────────*/
ddd = 123 /*a decimal number (expressed as a literal). */
ddd = '123' /*this is... | Give a code snippet in #REXX
Some programming languages have ways of expressing integer literals in bases other than the normal base ten.
Task
Show how integer literals can be expressed in as many bases as your language allows.
Note: this should not involve the calling of any functions/methods, but should be ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Compiler/virtual_machine_interpreter | Compiler/virtual machine interpreter | A virtual machine implements a computer in software.
Task[edit]
Write a virtual machine interpreter. This interpreter should be able to run virtual
assembly language programs created via the task. This is a
byte-coded, 32-bit word stack based virtual machine.
The program should read input from a file and/or stdin, an... | #D | D | //
// The Rosetta Code Virtual Machine in D.
//
// This code was migrated from an implementation in ATS. I have tried
// to keep it possible to compare the two languages easily, although
// in some cases the demonstration of "low level" techniques in ATS
// (such as avoiding memory leaks that might require garbage
// c... | Give a code snippet in #D
A virtual machine implements a computer in software.
Task[edit]
Write a virtual machine interpreter. This interpreter should be able to run virtual
assembly language programs created via the task. This is a
byte-coded, 32-bit word stack based virtual machine.
The program should read input f... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Faulhaber%27s_triangle | Faulhaber's triangle | Named after Johann Faulhaber, the rows of Faulhaber's triangle are the coefficients of polynomials that represent sums of integer powers, which are extracted from Faulhaber's formula:
∑
k
=
1
n
k
p
=
1
p
+
1
∑
j
=
0
p
(
p
+
1
j
)
B
j
n
p
+
1
−
j
{\displaystyle \sum _{k... | #Mathematica_.2F_Wolfram_Language | Mathematica / Wolfram Language | ClearAll[Faulhaber]
bernoulliB[1] := 1/2
bernoulliB[n_] := BernoulliB[n]
Faulhaber[n_, p_] := 1/(p + 1) Sum[Binomial[p + 1, j] bernoulliB[j] n^(p + 1 - j), {j, 0, p}]
Table[Rest@CoefficientList[Faulhaber[n, t], n], {t, 0, 9}] // Grid
Faulhaber[1000, 17] | Give a code snippet in #Mathematica_.2F_Wolfram_Language
Named after Johann Faulhaber, the rows of Faulhaber's triangle are the coefficients of polynomials that represent sums of integer powers, which are extracted from Faulhaber's formula:
∑
k
=
1
n
k
p
=
1
p
+
1
∑
j
=
0
p
(
p
+
1
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Increment_a_numerical_string | Increment a numerical string | Task
Increment a numerical string.
| #Brat | Brat | #Convert to integer, increment, then back to string
p ("100".to_i + 1).to_s #Prints 101 | Give a code snippet in #Brat
Task
Increment a numerical string.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Queue/Usage | Queue/Usage |
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Create a queue data structure and demonstrate its operations.
(For implementations of queues, see the FIFO task.)
Ope... | #Lasso | Lasso | push: queue->insert
pop: queue->get
empty: queue->size == 0
| Give a code snippet in #Lasso
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Create a queue data structure and demonstrate its operations.
(For implementations of que... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Abbreviations,_automatic | Abbreviations, automatic | The use of abbreviations (also sometimes called synonyms, nicknames, AKAs, or aliases) can be an
easy way to add flexibility when specifying or using commands, sub─commands, options, etc.
It would make a list of words easier to maintain (as words are added, changed, and/or deleted) if
the minimum abbrevia... | #TSE_SAL | TSE SAL |
STRING PROC FNStringGetExpressionRegularCharacterMetaEscapeS( STRING inS )
STRING s[255] = inS
s = StrReplace( "\", s, "\\", "gn" )
s = StrReplace( "{", s, "\{", "gn" )
s = StrReplace( "[", s, "\[", "gn" )
s = StrReplace( "}", s, "\}", "gn" )
s = StrReplace( "]", s, "\]", "gn" )
s = StrReplace( "*", s, "\*", "... | Give a code snippet in #TSE_SAL
The use of abbreviations (also sometimes called synonyms, nicknames, AKAs, or aliases) can be an
easy way to add flexibility when specifying or using commands, sub─commands, options, etc.
It would make a list of words easier to maintain (as words are added, changed, and/or d... | christopher/rosetta-code | |
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 ... | #F.23 | F# | type LazyList<'a> = Cons of 'a * Lazy<LazyList<'a>> // ': fix colouring
let rec hammings() =
let rec (-|-) (Cons(x, nxf) as xs) (Cons(y, nyf) as ys) =
if x < y then Cons(x, lazy(nxf.Value -|- ys))
elif x > y then Cons(y, lazy(xs -|- nyf.Value))
else Cons(x, lazy(nxf.Value -|- nyf.Value))
let rec inf_m... | Give a code snippet in #F.23
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 numbe... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Phrase_reversals | Phrase reversals | Task
Given a string of space separated words containing the following phrase:
rosetta code phrase reversal
Reverse the characters of the string.
Reverse the characters of each individual word in the string, maintaining original word order within the string.
Reverse the order of each word of the string, maintaini... | #C | C |
#include <stdio.h>
#include <string.h>
/* The functions used are destructive, so after each call the string needs
* to be copied over again. One could easily allocate new strings as
* required, but this way allows the caller to manage memory themselves */
char* reverse_section(char *s, size_t length)
{
if (... | Give a code snippet in #C
Task
Given a string of space separated words containing the following phrase:
rosetta code phrase reversal
Reverse the characters of the string.
Reverse the characters of each individual word in the string, maintaining original word order within the string.
Reverse the order of each wo... | christopher/rosetta-code | |
http://rosettacode.org/wiki/FASTA_format | FASTA format | In bioinformatics, long character strings are often encoded in a format called FASTA.
A FASTA file can contain several strings, each identified by a name marked by a > (greater than) character at the beginning of the line.
Task
Write a program that reads a FASTA file such as:
>Rosetta_Example_1
THERECANBENOSPACE
... | #Ring | Ring |
# Project : FAST format
a = ">Rosetta_Example_1
THERECANBENOSPACE
>Rosetta_Example_2
THERECANBESEVERAL
LINESBUTTHEYALLMUST
BECONCATENATED"
i = 1
while i <= len(a)
if substr(a,i,17) = ">Rosetta_Example_"
see nl
see substr(a,i,18) + ": " + nl
i = i + 17
else
if asc... | Give a code snippet in #Ring
In bioinformatics, long character strings are often encoded in a format called FASTA.
A FASTA file can contain several strings, each identified by a name marked by a > (greater than) character at the beginning of the line.
Task
Write a program that reads a FASTA file such as:
>Rosett... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Arbitrary-precision_integers_(included) | Arbitrary-precision integers (included) | Using the in-built capabilities of your language, calculate the integer value of:
5
4
3
2
... | #Forth | Forth | 388c388
< CREATE big_string 256 CHARS ALLOT
---
> CREATE big_string 500000 CHARS ALLOT
394c394
< big_string 256 CHARS + bighld ! ; \ Haydon p 67
---
> big_string 500000 CHARS + bighld ! ; \ Haydon p 67
403c403
< big_string 256 CHARS + \ One past end of string
---
> big_string 500000 CHARS + \ One past en... | Give a code snippet in #Forth
Using the in-built capabilities of your language, calculate the integer value of:
5
4
3
2
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Character_codes | Character codes |
Task
Given a character value in your language, print its code (could be ASCII code, Unicode code, or whatever your language uses).
Example
The character 'a' (lowercase letter A) has a code of 97 in ASCII (as well as Unicode, as ASCII forms the beginning of Unicode).
Conversely, given a code, print out... | #TI-89_BASIC | TI-89 BASIC | Prgm
Local k, s
ClrIO
Loop
Disp "Press a key, or ON to exit."
getKey() © clear buffer
0 → k : While k = 0 : getKey() → k : EndWhile
ClrIO
If k ≥ 256 Then
Disp "Not a character."
Disp "Code: " & string(k)
Else
char(k) → s ©
© char() and or... | Give a code snippet in #TI-89_BASIC
Task
Given a character value in your language, print its code (could be ASCII code, Unicode code, or whatever your language uses).
Example
The character 'a' (lowercase letter A) has a code of 97 in ASCII (as well as Unicode, as ASCII forms the beginning of Unicode).... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Generator/Exponential | Generator/Exponential | A generator is an executable entity (like a function or procedure) that contains code that yields a sequence of values, one at a time, so that each time you call the generator, the next value in the sequence is provided.
Generators are often built on top of coroutines or objects so that the internal state of the objec... | #SenseTalk | SenseTalk | // ExponentialGenerator.script
to initialize
set my base to 0
if my exponent is empty then set my exponent to 1 -- default if not given
end initialize
to handle nextValue
add 1 to my base
return my base to the power of my exponent
end nextValue | Give a code snippet in #SenseTalk
A generator is an executable entity (like a function or procedure) that contains code that yields a sequence of values, one at a time, so that each time you call the generator, the next value in the sequence is provided.
Generators are often built on top of coroutines or objects so t... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Ordered_words | Ordered words | An ordered word is a word in which the letters appear in alphabetic order.
Examples include abbey and dirt.
Task[edit]
Find and display all the ordered words in the dictionary unixdict.txt that have the longest word length.
(Examples that access the dictionary file locally assume that you have download... | #K | K | w@&d=|/d:#:'w:d@&&/'{~x<y}':'d:0:"unixdict.txt"
("abbott"
"accent"
"accept"
"access"
"accost"
"almost"
"bellow"
"billow"
"biopsy"
"chilly"
"choosy"
"choppy"
"effort"
"floppy"
"glossy"
"knotty") | Give a code snippet in #K
An ordered word is a word in which the letters appear in alphabetic order.
Examples include abbey and dirt.
Task[edit]
Find and display all the ordered words in the dictionary unixdict.txt that have the longest word length.
(Examples that access the dictionary file locally as... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Abstract_type | Abstract type | Abstract type is a type without instances or without definition.
For example in object-oriented programming using some languages, abstract types can be partial implementations of other types, which are to be derived there-from. An abstract type may provide implementation of some operations and/or components. Abstract ... | #Kotlin | Kotlin | // version 1.1
interface Announcer {
fun announceType()
// interface can contain non-abstract members but cannot store state
fun announceName() {
println("I don't have a name")
}
}
abstract class Animal: Announcer {
abstract fun makeNoise()
// abstract class can contain non-abstr... | Give a code snippet in #Kotlin
Abstract type is a type without instances or without definition.
For example in object-oriented programming using some languages, abstract types can be partial implementations of other types, which are to be derived there-from. An abstract type may provide implementation of some operati... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/For | Loops/For | “For” loops are used to make some block of code be iterated a number of times, setting a variable or parameter to a monotonically increasing integer value for each execution of the block of code.
Common extensions of this allow other counting patterns or iterating over abstract structures other than the integers.
... | #Modula-3 | Modula-3 | MODULE Stars EXPORTS Main;
IMPORT IO;
BEGIN
FOR i := 1 TO 5 DO
FOR j := 1 TO i DO
IO.Put("*");
END;
IO.Put("\n");
END;
END Stars. | Give a code snippet in #Modula-3
“For” loops are used to make some block of code be iterated a number of times, setting a variable or parameter to a monotonically increasing integer value for each execution of the block of code.
Common extensions of this allow other counting patterns or iterating over abstract stru... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Cumulative_standard_deviation | Cumulative standard deviation | Task[edit]
Write a stateful function, class, generator or co-routine that takes a series of floating point numbers, one at a time, and returns the running standard deviation of the series.
The task implementation should use the most natural programming style of those listed for the function in the implementation langu... | #Scala | Scala | import scala.math.sqrt
object StddevCalc extends App {
def calcAvgAndStddev[T](ts: Iterable[T])(implicit num: Fractional[T]): (T, Double) = {
def avg(ts: Iterable[T])(implicit num: Fractional[T]): T =
num.div(ts.sum, num.fromInt(ts.size)) // Leaving with type of function T
val mean: T = avg(ts) //... | Give a code snippet in #Scala
Task[edit]
Write a stateful function, class, generator or co-routine that takes a series of floating point numbers, one at a time, and returns the running standard deviation of the series.
The task implementation should use the most natural programming style of those listed for the funct... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Read_a_configuration_file | Read a configuration file | The task is to read a configuration file in standard configuration file format,
and set variables accordingly.
For this task, we have a configuration file as follows:
# This is a configuration file in standard configuration file format
#
# Lines beginning with a hash or a semicolon are ignored by the application
# pr... | #Erlang | Erlang |
-module( configuration_file ).
-export( [read/1, task/0] ).
read( File ) ->
{ok, Binary} = file:read_file( File ),
Lines = [X || <<First:8, _T/binary>> = X <- binary:split(Binary, <<"\n">>, [global]), First =/= $#, First =/= $;],
[option_from_binaries(binary:split(X, <<" ">>)) || X <- Lines].
task()... | Give a code snippet in #Erlang
The task is to read a configuration file in standard configuration file format,
and set variables accordingly.
For this task, we have a configuration file as follows:
# This is a configuration file in standard configuration file format
#
# Lines beginning with a hash or a semicolon are... | christopher/rosetta-code | |
http://rosettacode.org/wiki/User_input/Text | User input/Text | User input/Text is part of Short Circuit's Console Program Basics selection.
Task
Input a string and the integer 75000 from the text console.
See also: User input/Graphical
| #Retro | Retro | :example ("-)
'Enter_a_string:_ s:put s:get s:keep
[ 'Enter_75000:_ s:put s:get-word s:to-number nl #75000 eq? ] until
'Your_string_was:_'%s'\n s:format s:put ; | Give a code snippet in #Retro
User input/Text is part of Short Circuit's Console Program Basics selection.
Task
Input a string and the integer 75000 from the text console.
See also: User input/Graphical
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Objective-C | Objective-C | NSArray *args = [[NSProcessInfo processInfo] arguments];
NSLog(@"This program is named %@.", [args objectAtIndex:0]);
NSLog(@"There are %d arguments.", [args count] - 1);
for (i = 1; i < [args count]; ++i){
NSLog(@"the argument #%d is %@", i, [args objectAtIndex:i]);
} | Give a code snippet in #Objective-C
Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Pick_random_element | Pick random element | Demonstrate how to pick a random element from a list.
| #BaCon | BaCon | ' Pick random element
OPTION BASE 1
DECLARE words$[6]
FOR i = 1 TO 6 : READ words$[i] : NEXT
DATA "Alpha", "Beta", "Gamma", "Delta", "Epsilon", "Zeta"
element = RANDOM(6) + 1
PRINT "Chose ", element, ": ", words$[element] | Give a code snippet in #BaCon
Demonstrate how to pick a random element from a list.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Graph_colouring | Graph colouring |
A Graph is a collection of nodes
(or vertices), connected by edges (or not).
Nodes directly connected by edges are called neighbours.
In our representation of graphs, nodes are numbered and edges are represented
by the two node numbers connected by the edge separated by a dash.
Edges define the nodes being connected... | #Go | Go | package main
import (
"fmt"
"sort"
)
type graph struct {
nn int // number of nodes
st int // node numbering starts from
nbr [][]int // neighbor list for each node
}
type nodeval struct {
n int // number of node
v int // valence of node i.e. number of neighbors
}
func contai... | Give a code snippet in #Go
A Graph is a collection of nodes
(or vertices), connected by edges (or not).
Nodes directly connected by edges are called neighbours.
In our representation of graphs, nodes are numbered and edges are represented
by the two node numbers connected by the edge separated by a dash.
Edges defi... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Closures/Value_capture | Closures/Value capture | Task
Create a list of ten functions, in the simplest manner possible (anonymous functions are encouraged), such that the function at index i (you may choose to start i from either 0 or 1), when run, should return the square of the index, that is, i 2.
Display the result of runnin... | #Racket | Racket |
#lang racket
(define functions (for/list ([i 10]) (λ() (* i i))))
(map (λ(f) (f)) functions)
| Give a code snippet in #Racket
Task
Create a list of ten functions, in the simplest manner possible (anonymous functions are encouraged), such that the function at index i (you may choose to start i from either 0 or 1), when run, should return the square of the index, that is, i ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Thue-Morse | Thue-Morse | Task
Create a Thue-Morse sequence.
See also
YouTube entry: The Fairest Sharing Sequence Ever
YouTube entry: Math and OCD - My story with the Thue-Morse sequence
Task: Fairshare between two and more
| #Go | Go | // prints the first few members of the Thue-Morse sequence
package main
import (
"fmt"
"bytes"
)
// sets tmBuffer to the next member of the Thue-Morse sequence
// tmBuffer must contain a valid Thue-Morse sequence member before the call
func nextTMSequenceMember( tmBuffer * bytes.Buffer ) {
// "flip" t... | Give a code snippet in #Go
Task
Create a Thue-Morse sequence.
See also
YouTube entry: The Fairest Sharing Sequence Ever
YouTube entry: Math and OCD - My story with the Thue-Morse sequence
Task: Fairshare between two and more
| christopher/rosetta-code |
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