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
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http://rosettacode.org/wiki/Make_directory_path | Make directory path | Task
Create a directory and any missing parents.
This task is named after the posix mkdir -p command, and several libraries which implement the same behavior.
Please implement a function of a single path string (for example ./path/to/dir) which has the above side-effect.
If the directory already exists, return succe... | #ERRE | ERRE | OS_MKDIR("C:\EXAMPLES\03192015") | Give a code snippet in #ERRE
Task
Create a directory and any missing parents.
This task is named after the posix mkdir -p command, and several libraries which implement the same behavior.
Please implement a function of a single path string (for example ./path/to/dir) which has the above side-effect.
If the director... | 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... | #C | C | #include <stdlib.h>
#include <stdio.h>
#include <time.h>
#define lower_limit 0
#define upper_limit 100
int main(){
int number, guess;
srand( time( 0 ) );
number = lower_limit + rand() % (upper_limit - lower_limit + 1);
printf( "Guess the number between %d and %d: ", lower_limit, upper_limit );
while... | Give a code snippet in #C
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... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Walk_a_directory/Recursively | Walk a directory/Recursively | Task
Walk a given directory tree and print files matching a given pattern.
Note: This task is for recursive methods. These tasks should read an entire directory tree, not a single directory.
Note: Please be careful when running any code examples found here.
Related task
Walk a directory/Non-recursively ... | #Common_Lisp | Common Lisp | (ql:quickload :cl-fad)
(defun mapc-directory-tree (fn directory &key (depth-first-p t))
(dolist (entry (cl-fad:list-directory directory))
(unless depth-first-p
(funcall fn entry))
(when (cl-fad:directory-pathname-p entry)
(mapc-directory-tree fn entry))
(when depth-first-p
(funcall fn en... | Give a code snippet in #Common_Lisp
Task
Walk a given directory tree and print files matching a given pattern.
Note: This task is for recursive methods. These tasks should read an entire directory tree, not a single directory.
Note: Please be careful when running any code examples found here.
Related task
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Ranking_methods | Ranking methods |
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
... | #Tcl | Tcl | proc rank {rankingMethod sortedList} {
# Extract the groups in the data (this is pointless for ordinal...)
set s [set group [set groups {}]]
foreach {score who} $sortedList {
if {$score != $s} {
lappend groups [llength $group]
set s $score
set group {}
}
lappend group $who
}
lappen... | Give a code snippet in #Tcl
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... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Flow-control_structures | Flow-control structures | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
Document common flow-control structures.
One common example of a flow-control structure is the goto construct.
Note that Conditional Struc... | #Raku | Raku | TOWN: goto TOWN; | Give a code snippet in #Raku
Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
Document common flow-control structures.
One common example of a flow-control structure is the goto construct.
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Count_in_octal | Count in octal | Task
Produce a sequential count in octal, starting at zero, and using an increment of a one for each consecutive number.
Each number should appear on a single line, and the program should count until terminated, or until the maximum value of the numeric type in use is reached.
Related task
Integer sequ... | #Nanoquery | Nanoquery | i = 0
while i < 2^64
println format("%o", i)
i += 1
end | Give a code snippet in #Nanoquery
Task
Produce a sequential count in octal, starting at zero, and using an increment of a one for each consecutive number.
Each number should appear on a single line, and the program should count until terminated, or until the maximum value of the numeric type in use is reache... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Bitmap/Midpoint_circle_algorithm | Bitmap/Midpoint circle algorithm | Task
Using the data storage type defined on this page for raster images,
write an implementation of the midpoint circle algorithm (also known as Bresenham's circle algorithm).
(definition on Wikipedia).
| #bash | bash | #! /bin/bash
# Based on https://en.wikipedia.org/wiki/Midpoint_circle_algorithm
function putpixel {
echo -en "\e[$2;$1H#"
}
function drawcircle {
x0=$1
y0=$2
radius=$3
for y in $( seq $((y0-radius)) $((y0+radius)) )
do
echo -en "\e[${y}H"
for x in $( seq $((x0+radius)) )
do
... | Give a code snippet in #bash
Task
Using the data storage type defined on this page for raster images,
write an implementation of the midpoint circle algorithm (also known as Bresenham's circle algorithm).
(definition on Wikipedia).
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Rock-paper-scissors | Rock-paper-scissors | Task
Implement the classic children's game Rock-paper-scissors, as well as a simple predictive AI (artificial intelligence) player.
Rock Paper Scissors is a two player game.
Each player chooses one of rock, paper or scissors, without knowing the other player's choice.
The winner is decided by a set of rules:
... | #Prolog | Prolog | play :-
findall(P,beats(P,_),Prev),
play(Prev).
play(Prev) :-
write('your choice? '),
read(P),
random_member(C, Prev),
format('The computer chose ~p~n', C),
result(C,P,Prev,Next),
!,
play(Next).
result(C,P,R,[C|R]) :-
beats(C,P),
format('Computer wins.~n').
result(C,P,R,[B|R]) :-
beats(P,C),... | Give a code snippet in #Prolog
Task
Implement the classic children's game Rock-paper-scissors, as well as a simple predictive AI (artificial intelligence) player.
Rock Paper Scissors is a two player game.
Each player chooses one of rock, paper or scissors, without knowing the other player's choice.
The winne... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Generate_lower_case_ASCII_alphabet | Generate lower case ASCII alphabet | Task
Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence.
For this basic task use a reliable style of coding, a sty... | #jq | jq | "az" | explode | [range( .[0]; 1+.[1] )] | implode' | Give a code snippet in #jq
Task
Generate an array, list, lazy sequence, or even an indexable string of all the lower case ASCII characters, from a to z. If the standard library contains such a sequence, show how to access it, but don't fail to show how to generate a similar sequence.
For this basic task use a rel... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Euler%27s_identity | Euler's identity |
This page uses content from Wikipedia. The original article was at Euler's_identity. 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)
In mathematics, Euler's identity is the equality:
... | #11l | 11l | print(math:e ^ (math:pi * 1i) + 1) | Give a code snippet in #11l
This page uses content from Wikipedia. The original article was at Euler's_identity. 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)
In mathematics, Euler's identity is... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Averages/Arithmetic_mean | Averages/Arithmetic mean | Task[edit]
Write a program to find the mean (arithmetic average) of a numeric vector.
In case of a zero-length input, since the mean of an empty set of numbers is ill-defined, the program may choose to behave in any way it deems appropriate, though if the programming language has an established convention for conveyin... | #C.2B.2B | C++ | #include <vector>
double mean(const std::vector<double>& numbers)
{
if (numbers.size() == 0)
return 0;
double sum = 0;
for (std::vector<double>::iterator i = numbers.begin(); i != numbers.end(); i++)
sum += *i;
return sum / numbers.size();
} | Give a code snippet in #C.2B.2B
Task[edit]
Write a program to find the mean (arithmetic average) of a numeric vector.
In case of a zero-length input, since the mean of an empty set of numbers is ill-defined, the program may choose to behave in any way it deems appropriate, though if the programming language has an es... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/For_with_a_specified_step | Loops/For with a specified step |
Task
Demonstrate a for-loop where the step-value is greater than one.
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 loop b... | #REXX | REXX | do x=1 to 10 by 1.5
say x
end | Give a code snippet in #REXX
Task
Demonstrate a for-loop where the step-value is greater than one.
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/Incr... | 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
| #FutureBasic | FutureBasic | window 1
dim as pointer functionOneAddress
def fn FunctionOne( x as long, y as long ) as long = (x + y) ^ 2
functionOneAddress = @fn FunctionOne
def fn FunctionTwo( x as long, y as long ) using functionOneAddress
print fn FunctionTwo( 12, 12 )
HandleEvents | Give a code snippet in #FutureBasic
Task
Pass a function as an argument to another function.
Related task
First-class functions
| christopher/rosetta-code | |
http://rosettacode.org/wiki/String_concatenation | String concatenation | String concatenation
You are encouraged to solve this task according to the task description, using any language you may know.
Task
Create a string variable equal to any text value.
Create another string variable whose value is the original variable concatenated with another string literal.
To illustrate the operat... | #Swift | Swift | let s = "hello"
println(s + " literal")
let s1 = s + " literal"
println(s1) | Give a code snippet in #Swift
String concatenation
You are encouraged to solve this task according to the task description, using any language you may know.
Task
Create a string variable equal to any text value.
Create another string variable whose value is the original variable concatenated with another string lit... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Bitmap | Bitmap | Show a basic storage type to handle a simple RGB raster graphics image,
and some primitive associated functions.
If possible provide a function to allocate an uninitialised image,
given its width and height, and provide 3 additional functions:
one to fill an image with a plain RGB color,
one to set a given pixe... | #Crystal | Crystal |
class RGBColor
getter red, green, blue
def initialize(@red = 0_u8, @green = 0_u8, @blue = 0_u8)
end
RED = new(red: 255_u8)
GREEN = new(green: 255_u8)
BLUE = new(blue: 255_u8)
BLACK = new
WHITE = new(255_u8, 255_u8, 255_u8)
end
class Pixmap
getter width, height
@data : Array(Array(RGBColor... | Give a code snippet in #Crystal
Show a basic storage type to handle a simple RGB raster graphics image,
and some primitive associated functions.
If possible provide a function to allocate an uninitialised image,
given its width and height, and provide 3 additional functions:
one to fill an image with a plain RGB ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Classes | Classes | In object-oriented programming class is a set (a transitive closure) of types bound by the relation of inheritance. It is said that all types derived from some base type T and the type T itself form a class T.
The first type T from the class T sometimes is called the root type of the class.
A class of types itself, a... | #Clojure | Clojure |
; You can think of this as an interface
(defprotocol Foo (getFoo [this]))
; Generates Example1 Class with foo as field, with method that returns foo.
(defrecord Example1 [foo] Foo (getFoo [this] foo))
; Create instance and invoke our method to return field value
(-> (Example1. "Hi") .getFoo)
"Hi" | Give a code snippet in #Clojure
In object-oriented programming class is a set (a transitive closure) of types bound by the relation of inheritance. It is said that all types derived from some base type T and the type T itself form a class T.
The first type T from the class T sometimes is called the root type of the c... | 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... | #GDScript | GDScript | func Doors(door_count:int) -> void :
var doors : Array
doors.resize(door_count)
# Note : Initialization is not necessarily mandatory (by default values are false)
# Intentionally left here
for i in door_count :
doors[i] = false
# do visits
for i in door_count :
for j in range(i,door_count,i+1)... | Give a code snippet in #GDScript
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/Pythagorean_quadruples | Pythagorean quadruples |
One form of Pythagorean quadruples is (for positive integers a, b, c, and d):
a2 + b2 + c2 = d2
An example:
22 + 32 + 62 = 72
which is:
4 + 9 + 36 = 49
Task
For positive integers up 2,200 (inclusive), for all values of ... | #C.2B.2B | C++ | #include <iostream>
#include <vector>
constexpr int N = 2200;
constexpr int N2 = 2 * N * N;
int main() {
using namespace std;
vector<bool> found(N + 1);
vector<bool> aabb(N2 + 1);
int s = 3;
for (int a = 1; a < N; ++a) {
int aa = a * a;
for (int b = 1; b < N; ++b) {
... | Give a code snippet in #C.2B.2B
One form of Pythagorean quadruples is (for positive integers a, b, c, and d):
a2 + b2 + c2 = d2
An example:
22 + 32 + 62 = 72
which is:
4 + 9 + 36 = 49
Task
For positive integers up 2,200 (i... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Longest_common_subsequence | Longest common subsequence | Introduction
Define a subsequence to be any output string obtained by deleting zero or more symbols from an input string.
The Longest Common Subsequence (LCS) is a subsequence of maximum length common to two or more strings.
Let A ≡ A[0]… A[m - 1] and B ≡ B[0]… B[n - 1], m < n be strings drawn from an alphabet Σ of ... | #jq | jq | def lcs(xstr; ystr):
if (xstr == "" or ystr == "") then ""
else
xstr[0:1] as $x
| xstr[1:] as $xs
| ystr[1:] as $ys
| if ($x == ystr[0:1]) then ($x + lcs($xs; $ys))
else
lcs(xstr; $ys) as $one
| lcs($xs; ystr) as $two
| if ($one|length) > ($two|length) then $one else $two end
... | Give a code snippet in #jq
Introduction
Define a subsequence to be any output string obtained by deleting zero or more symbols from an input string.
The Longest Common Subsequence (LCS) is a subsequence of maximum length common to two or more strings.
Let A ≡ A[0]… A[m - 1] and B ≡ B[0]… B[n - 1], m < n be strings ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Determine_if_only_one_instance_is_running | Determine if only one instance is running | This task is to determine if there is only one instance of an application running. If the program discovers that an instance of it is already running, then it should display a message indicating that it is already running and exit.
| #FreeBASIC | FreeBASIC | Shell("tasklist > temp.txt")
Dim linea As String
Open "temp.txt" For Input As #1
Do While Not Eof(1)
Line Input #1, linea
If Instr(linea, "fbc.exe") = 0 Then Print "Task is Running" : Exit Do
Loop
Close #1
Shell("del temp.txt")
Sleep | Give a code snippet in #FreeBASIC
This task is to determine if there is only one instance of an application running. If the program discovers that an instance of it is already running, then it should display a message indicating that it is already running and exit.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Add_a_variable_to_a_class_instance_at_runtime | Add a variable to a class instance at runtime | Demonstrate how to dynamically add variables to an object (a class instance) at runtime.
This is useful when the methods/variables of an instance are based on a data file that isn't available until runtime. Hal Fulton gives an example of creating an OO CSV parser at An Exercise in Metaprogramming with Ruby. This is re... | #jq | jq | {"a":1} as $a | ($a + {"b":2}) as $a | $a
| Give a code snippet in #jq
Demonstrate how to dynamically add variables to an object (a class instance) at runtime.
This is useful when the methods/variables of an instance are based on a data file that isn't available until runtime. Hal Fulton gives an example of creating an OO CSV parser at An Exercise in Metaprogr... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Emirp_primes | Emirp primes | An emirp (prime spelled backwards) are primes that when reversed (in their decimal representation) are a different prime.
(This rules out palindromic primes.)
Task
show the first twenty emirps
show all emirps between 7,700 and 8,000
show the 10,000th emirp
In each list, the numbe... | #Elixir | Elixir | defmodule Emirp do
defp prime?(2), do: true
defp prime?(n) when n<2 or rem(n,2)==0, do: false
defp prime?(n), do: prime?(n,3)
defp prime?(n,k) when n<k*k, do: true
defp prime?(n,k) when rem(n,k)==0, do: false
defp prime?(n,k), do: prime?(n,k+2)
def emirp?(n) do
if prime?(n) do
reverse = to_s... | Give a code snippet in #Elixir
An emirp (prime spelled backwards) are primes that when reversed (in their decimal representation) are a different prime.
(This rules out palindromic primes.)
Task
show the first twenty emirps
show all emirps between 7,700 and 8,000
show the 10,000th ... | 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 ... | #Forth | Forth |
: dig.num \ returns input number and the number of its digits ( n -- n n1 )
dup
0 swap
begin
swap 1 + swap
dup 10 >= while
10 /
repeat
drop ;
: to.self \ returns input number raised to the power of itself ( n -- n^n... | Give a code snippet in #Forth
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
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Dutch_national_flag_problem | Dutch national flag problem |
The Dutch national flag is composed of three coloured bands in the order:
red (top)
then white, and
lastly blue (at the bottom).
The problem posed by Edsger Dijkstra is:
Given a number of red, blue and white balls in random order, arrange them in the order of the colours in the Dutch national fla... | #UNIX_Shell | UNIX Shell | COLORS=(red white blue)
# to go from name to number, we make variables out of the color names
# (e.g. the variable "$red" has value "1").
for (( i=0; i<${#COLORS[@]}; ++i )); do
eval ${COLORS[i]}=$i
done
# Make a random list
function random_balls {
local -i n="$1"
local -i i
local balls=()
for (( i=0; i ... | Give a code snippet in #UNIX_Shell
The Dutch national flag is composed of three coloured bands in the order:
red (top)
then white, and
lastly blue (at the bottom).
The problem posed by Edsger Dijkstra is:
Given a number of red, blue and white balls in random order, arrange them in the order of t... | christopher/rosetta-code | |
http://rosettacode.org/wiki/M%C3%B6bius_function | Möbius function | The classical Möbius function: μ(n) is an important multiplicative function in number theory and combinatorics.
There are several ways to implement a Möbius function.
A fairly straightforward method is to find the prime factors of a positive integer n, then define μ(n) based on the sum of the primitive factors. It ha... | #Fortran | Fortran |
program moebius
use iso_fortran_env, only: output_unit
integer, parameter :: mu_max=1000000, line_break=20
integer, parameter :: sqroot=int(sqrt(real(mu_max)))
integer :: i, j
integer, dimension(mu_max) :: mu
mu = 1
do i = 2, sqroot
if (... | Give a code snippet in #Fortran
The classical Möbius function: μ(n) is an important multiplicative function in number theory and combinatorics.
There are several ways to implement a Möbius function.
A fairly straightforward method is to find the prime factors of a positive integer n, then define μ(n) based on the su... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Substring | Substring |
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
Concatenation |
Interpolation |... | #UNIX_Shell | UNIX Shell | str="abc qrdef qrghi"
n=6
m=3
expr "x$str" : "x.\{$n\}\(.\{1,$m\}\)"
expr "x$str" : "x.\{$n\}\(.*\)"
printf '%s\n' "${str%?}"
expr "r${str#*r}" : "\(.\{1,$m\}\)"
expr "qr${str#*qr}" : "\(.\{1,$m\}\)" | Give a code snippet in #UNIX_Shell
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 Operat... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Bulls_and_cows | Bulls and cows | Bulls and Cows
Task
Create a four digit random number from the digits 1 to 9, without duplication.
The program should:
ask for guesses to this number
reject guesses that are malformed
print the score for the guess
The score is computed as:
The player wins if the guess is the same as the random... | #E | E | def Digit := 1..9
def Number := Tuple[Digit,Digit,Digit,Digit]
/** Choose a random number to be guessed. */
def pick4(entropy) {
def digits := [1,2,3,4,5,6,7,8,9].diverge()
# Partial Fisher-Yates shuffle
for i in 0..!4 {
def other := entropy.nextInt(digits.size() - i) + i
def t := digits... | Give a code snippet in #E
Bulls and Cows
Task
Create a four digit random number from the digits 1 to 9, without duplication.
The program should:
ask for guesses to this number
reject guesses that are malformed
print the score for the guess
The score is computed as:
The player wins if the gues... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Longest_common_subsequence | Longest common subsequence | Introduction
Define a subsequence to be any output string obtained by deleting zero or more symbols from an input string.
The Longest Common Subsequence (LCS) is a subsequence of maximum length common to two or more strings.
Let A ≡ A[0]… A[m - 1] and B ≡ B[0]… B[n - 1], m < n be strings drawn from an alphabet Σ of ... | #Swift | Swift | rlcs(_ s1: String, _ s2: String) -> String {
if s1.count == 0 || s2.count == 0 {
return ""
} else if s1[s1.index(s1.endIndex, offsetBy: -1)] == s2[s2.index(s2.endIndex, offsetBy: -1)] {
return rlcs(String(s1[s1.startIndex..<s1.index(s1.endIndex, offsetBy: -1)]),
String(s2[s2.start... | Give a code snippet in #Swift
Introduction
Define a subsequence to be any output string obtained by deleting zero or more symbols from an input string.
The Longest Common Subsequence (LCS) is a subsequence of maximum length common to two or more strings.
Let A ≡ A[0]… A[m - 1] and B ≡ B[0]… B[n - 1], m < n be strin... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Numerical_integration | Numerical integration | Write functions to calculate the definite integral of a function ƒ(x) using all five of the following methods:
rectangular
left
right
midpoint
trapezium
Simpson's
composite
Your functions should take in the upper and lower bounds (a and b), and the number of approximations to make in that range (n).
Assume t... | #Julia | Julia | function simpson(f::Function, a::Number, b::Number, n::Integer)
h = (b - a) / n
s = f(a + h / 2)
for i in 1:(n-1)
s += f(a + h * i + h / 2) + f(a + h * i) / 2
end
return h/6 * (f(a) + f(b) + 4*s)
end
rst =
simpson(x -> x ^ 3, 0, 1, 100),
simpson(x -> 1 / x, 1, 100, 1000),
simps... | Give a code snippet in #Julia
Write functions to calculate the definite integral of a function ƒ(x) using all five of the following methods:
rectangular
left
right
midpoint
trapezium
Simpson's
composite
Your functions should take in the upper and lower bounds (a and b), and the number of approximations to ma... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Record_sound | Record sound | Record a monophonic 16-bit PCM sound into either memory space, a file or array.
(This task neglects to specify the sample rate, and whether to use signed samples.
The programs in this page might use signed 16-bit or unsigned 16-bit samples, at 8000 Hz, 44100 Hz, or any other sample rate.
Therefore, these programs migh... | #Go | Go | package main
import (
"bufio"
"fmt"
"log"
"os"
"os/exec"
"strconv"
)
func check(err error) {
if err != nil {
log.Fatal(err)
}
}
func main() {
scanner := bufio.NewScanner(os.Stdin)
name := ""
for name == "" {
fmt.Print("Enter output file name (without ext... | Give a code snippet in #Go
Record a monophonic 16-bit PCM sound into either memory space, a file or array.
(This task neglects to specify the sample rate, and whether to use signed samples.
The programs in this page might use signed 16-bit or unsigned 16-bit samples, at 8000 Hz, 44100 Hz, or any other sample rate.
Th... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Binary_search | Binary search | A binary search divides a range of values into halves, and continues to narrow down the field of search until the unknown value is found. It is the classic example of a "divide and conquer" algorithm.
As an analogy, consider the children's game "guess a number." The scorer has a secret number, and will only tell the p... | #Clojure | Clojure | (defn bsearch
([coll t]
(bsearch coll 0 (dec (count coll)) t))
([coll l u t]
(if (> l u) -1
(let [m (quot (+ l u) 2) mth (nth coll m)]
(cond
; the middle element is greater than t
; so search the lower half
(> mth t) (recur coll l (dec m) t)
; the middle... | Give a code snippet in #Clojure
A binary search divides a range of values into halves, and continues to narrow down the field of search until the unknown value is found. It is the classic example of a "divide and conquer" algorithm.
As an analogy, consider the children's game "guess a number." The scorer has a secret... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Superellipse | Superellipse | A superellipse is a geometric figure defined as the set of all points (x, y) with
|
x
a
|
n
+
|
y
b
|
n
=
1
,
{\displaystyle \left|{\frac {x}{a}}\right|^{n}\!+\left|{\frac {y}{b}}\right|^{n}\!=1,}
where n, a, and b are positive numbers.
Task
Draw a superellipse with n = 2.5, and a... | #Kotlin | Kotlin | // version 1.1.2
import java.awt.*
import java.awt.geom.Path2D
import javax.swing.*
import java.lang.Math.pow
/* assumes a == b */
class SuperEllipse(val n: Double, val a: Int) : JPanel() {
init {
require(n > 0.0 && a > 0)
preferredSize = Dimension(650, 650)
background = Color.black
... | Give a code snippet in #Kotlin
A superellipse is a geometric figure defined as the set of all points (x, y) with
|
x
a
|
n
+
|
y
b
|
n
=
1
,
{\displaystyle \left|{\frac {x}{a}}\right|^{n}\!+\left|{\frac {y}{b}}\right|^{n}\!=1,}
where n, a, and b are positive numbers.
Task
Draw a ... | 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... | #Nim | Nim | proc isSemiPrime(k: int): bool =
var
i = 2
count = 0
x = k
while i <= x and count < 3:
if x mod i == 0:
x = x div i
inc count
else:
inc i
result = count == 2
for k in 1675..1680:
echo k, (if k.isSemiPrime(): " is" else: " isn’t"), " semi-prime" | Give a code snippet in #Nim
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 chose... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/Foreach | Loops/Foreach | Loop through and print each element in a collection in order.
Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downward for... | #Java | Java | Iterable<Type> collect;
...
for(Type i:collect){
System.out.println(i);
} | Give a code snippet in #Java
Loop through and print each element in a collection in order.
Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Empty_string | Empty string | Languages may have features for dealing specifically with empty strings
(those containing no characters).
Task
Demonstrate how to assign an empty string to a variable.
Demonstrate how to check that a string is empty.
Demonstrate how to check that a string is not empty.
Other tasks related to string oper... | #Wee_Basic | Wee Basic | let string$=""
if string$=""
print 1 "The string is empty."
elseif string$<>""
print 1 "The string is not empty."
endif
end | Give a code snippet in #Wee_Basic
Languages may have features for dealing specifically with empty strings
(those containing no characters).
Task
Demonstrate how to assign an empty string to a variable.
Demonstrate how to check that a string is empty.
Demonstrate how to check that a string is not empty.
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Draw_a_sphere | Draw a sphere | Task
Draw a sphere.
The sphere can be represented graphically, or in ASCII art, depending on the language capabilities.
Either static or rotational projection is acceptable for this task.
Related tasks
draw a cuboid
draw a rotating cube
write language name in 3D ASCII
draw a Deathstar
| #Pascal | Pascal | use strict;
use warnings;
my $x = my $y = 255;
$x |= 1; # must be odd
my $depth = 255;
my $light = Vector->new(rand, rand, rand)->normalized;
print "P2\n$x $y\n$depth\n";
my ($r, $ambient) = (($x - 1)/2, 0);
my ($r2) = $r ** 2;
{
for my $x (-$r .. $r) {
my $x2 = $x**2;
for my $y (-$r .. $r) {
my $y2 ... | Give a code snippet in #Pascal
Task
Draw a sphere.
The sphere can be represented graphically, or in ASCII art, depending on the language capabilities.
Either static or rotational projection is acceptable for this task.
Related tasks
draw a cuboid
draw a rotating cube
write language name in 3D ASCII
draw a D... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Brazilian_numbers | Brazilian numbers | Brazilian numbers are so called as they were first formally presented at the 1994 math Olympiad Olimpiada Iberoamericana de Matematica in Fortaleza, Brazil.
Brazilian numbers are defined as:
The set of positive integer numbers where each number N has at least one natural number B where 1 < B < N-1 where the represent... | #11l | 11l | F isPrime(n)
I n % 2 == 0
R n == 2
I n % 3 == 0
R n == 3
V d = 5
L d * d <= n
I n % d == 0
R 0B
I n % (d + 2) == 0
R 0B
d += 6
R 1B
F sameDigits(=n, b)
V d = n % b
n I/= b
I d == 0
R 0B
L n > 0
I n % b != d
R 0B
n I/... | Give a code snippet in #11l
Brazilian numbers are so called as they were first formally presented at the 1994 math Olympiad Olimpiada Iberoamericana de Matematica in Fortaleza, Brazil.
Brazilian numbers are defined as:
The set of positive integer numbers where each number N has at least one natural number B where 1 ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Write_float_arrays_to_a_text_file | Write float arrays to a text file | Task
Write two equal-sized numerical arrays 'x' and 'y' to
a two-column text file named 'filename'.
The first column of the file contains values from an 'x'-array with a
given 'xprecision', the second -- values from 'y'-array with 'yprecision'.
For example, considering:
x = {1, 2, 3, 1e11};
y = {1, 1.41421356... | #Lingo | Lingo | on saveFloatLists (filename, x, y, xprecision, yprecision)
eol = numtochar(10) -- LF
fp = xtra("fileIO").new()
fp.openFile(tFile, 2)
cnt = x.count
repeat with i = 1 to cnt
the floatPrecision = xprecision
fp.writeString(string(x[i])
fp.writeString(TAB)
the floatPrecision = yprecision
fp.wri... | Give a code snippet in #Lingo
Task
Write two equal-sized numerical arrays 'x' and 'y' to
a two-column text file named 'filename'.
The first column of the file contains values from an 'x'-array with a
given 'xprecision', the second -- values from 'y'-array with 'yprecision'.
For example, considering:
x = {1, 2, ... | 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... | #11l | 11l | V MAX_PRIME = 1000000
V primes = [1B] * MAX_PRIME
primes[0] = primes[1] = 0B
V i = 2
L i * i < MAX_PRIME
L(j) (i * i .< MAX_PRIME).step(i)
primes[j] = 0B
i++
L i < MAX_PRIME & !primes[i]
i++
F left_trunc(=n)
V tens = 1
L tens < n
tens *= 10
L n != 0
I !:primes[n]
... | Give a code snippet in #11l
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... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Matrix-exponentiation_operator | Matrix-exponentiation operator | Most programming languages have a built-in implementation of exponentiation for integers and reals only.
Task
Demonstrate how to implement matrix exponentiation as an operator.
| #Liberty_BASIC | Liberty BASIC |
MatrixD$ ="3, 3, 0.86603, 0.50000, 0.00000, -0.50000, 0.86603, 0.00000, 0.00000, 0.00000, 1.00000"
print "Exponentiation of a matrix"
call DisplayMatrix MatrixD$
print " Raised to power 5 ="
MatrixE$ =MatrixToPower$( MatrixD$, 5)
call DisplayMatrix MatrixE$
print " Raised to... | Give a code snippet in #Liberty_BASIC
Most programming languages have a built-in implementation of exponentiation for integers and reals only.
Task
Demonstrate how to implement matrix exponentiation as an operator.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Count_in_octal | Count in octal | Task
Produce a sequential count in octal, starting at zero, and using an increment of a one for each consecutive number.
Each number should appear on a single line, and the program should count until terminated, or until the maximum value of the numeric type in use is reached.
Related task
Integer sequ... | #Icon_and_Unicon | Icon and Unicon | link convert # To get exbase10 method
procedure main()
limit := 8r37777777777
every write(exbase10(seq(0)\limit, 8))
end | Give a code snippet in #Icon_and_Unicon
Task
Produce a sequential count in octal, starting at zero, and using an increment of a one for each consecutive number.
Each number should appear on a single line, and the program should count until terminated, or until the maximum value of the numeric type in use is ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Write_entire_file | Write entire file | Task
(Over)write a file so that it contains a string.
The reverse of Read entire file—for when you want to update or create a file which you would read in its entirety all at once.
| #Mathematica.2FWolfram_Language | Mathematica/Wolfram Language | Export["filename.txt","contents string"] | Give a code snippet in #Mathematica.2FWolfram_Language
Task
(Over)write a file so that it contains a string.
The reverse of Read entire file—for when you want to update or create a file which you would read in its entirety all at once.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Leonardo_numbers | Leonardo numbers |
Leonardo numbers are also known as the Leonardo series.
The Leonardo numbers are a sequence of numbers defined by:
L(0) = 1 [1st equation]
L(1) = 1 [2nd equation]
L(n) = L(n-1) + L(n-2) + 1 ... | #Kotlin | Kotlin | // version 1.1.2
fun leonardo(n: Int, l0: Int = 1, l1: Int = 1, add: Int = 1): IntArray {
val leo = IntArray(n)
leo[0] = l0
leo[1] = l1
for (i in 2 until n) leo[i] = leo[i - 1] + leo[i - 2] + add
return leo
}
fun main(args: Array<String>) {
println("The first 25 Leonardo numbers with L[0] = ... | Give a code snippet in #Kotlin
Leonardo numbers are also known as the Leonardo series.
The Leonardo numbers are a sequence of numbers defined by:
L(0) = 1 [1st equation]
L(1) = 1 [2nd equation]
L(n) ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Angle_difference_between_two_bearings | Angle difference between two bearings | Finding the angle between two bearings is often confusing.[1]
Task
Find the angle which is the result of the subtraction b2 - b1, where b1 and b2 are the bearings.
Input bearings are expressed in the range -180 to +180 degrees.
The result is also expressed in the range -180 to +180 degrees.
... | #Ring | Ring |
# Project : Angle difference between two bearings
decimals(4)
see "Input in -180 to +180 range:" + nl
see getDifference(20.0, 45.0) + nl
see getDifference(-45.0, 45.0) + nl
see getDifference(-85.0, 90.0) + nl
see getDifference(-95.0, 90.0) + nl
see getDifference(-45.0, 125.0) + nl
see getDifference(-45.0, 145.0) + ... | Give a code snippet in #Ring
Finding the angle between two bearings is often confusing.[1]
Task
Find the angle which is the result of the subtraction b2 - b1, where b1 and b2 are the bearings.
Input bearings are expressed in the range -180 to +180 degrees.
The result is also expressed in the range -... | christopher/rosetta-code | |
http://rosettacode.org/wiki/21_game | 21 game | 21 game
You are encouraged to solve this task according to the task description, using any language you may know.
21 is a two player game, the game is played by choosing
a number (1, 2, or 3) to be added to the running total.
The game is won by the player whose chosen number causes the running total
to reach exactly ... | #C.23 | C# | // 21 Game
using System;
namespace _21Game
{
public class Program
{
private const string computerPlayer = "Computer";
private const string humanPlayer = "Player 1";
public static string SwapPlayer(string currentPlayer)
{
if (currentPlayer == computerPlayer)
... | Give a code snippet in #C.23
21 game
You are encouraged to solve this task according to the task description, using any language you may know.
21 is a two player game, the game is played by choosing
a number (1, 2, or 3) to be added to the running total.
The game is won by the player whose chosen number causes the r... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Temperature_conversion | Temperature conversion | There are quite a number of temperature scales. For this task we will concentrate on four of the perhaps best-known ones:
Kelvin, Celsius, Fahrenheit, and Rankine.
The Celsius and Kelvin scales have the same magnitude, but different null points.
0 degrees Celsius corresponds to 273.15 kelvin.
0 kelvin is absolute z... | #PHP | PHP |
while (true) {
echo "\nEnter a value in kelvin (q to quit): ";
if ($kelvin = trim(fgets(STDIN))) {
if ($kelvin == 'q') {
echo 'quitting';
break;
}
if (is_numeric($kelvin)) {
$kelvin = floatVal($kelvin);
if ($kelvin >= 0) {
... | Give a code snippet in #PHP
There are quite a number of temperature scales. For this task we will concentrate on four of the perhaps best-known ones:
Kelvin, Celsius, Fahrenheit, and Rankine.
The Celsius and Kelvin scales have the same magnitude, but different null points.
0 degrees Celsius corresponds to 273.15 ke... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Pentomino_tiling | Pentomino tiling | A pentomino is a polyomino that consists of 5 squares. There are 12 pentomino shapes,
if you don't count rotations and reflections. Most pentominoes can form their own mirror image through
rotation, but some of them have to be flipped over.
I ... | #Go | Go | package main
import (
"fmt"
"math/rand"
"time"
)
var F = [][]int{
{1, -1, 1, 0, 1, 1, 2, 1}, {0, 1, 1, -1, 1, 0, 2, 0},
{1, 0, 1, 1, 1, 2, 2, 1}, {1, 0, 1, 1, 2, -1, 2, 0},
{1, -2, 1, -1, 1, 0, 2, -1}, {0, 1, 1, 1, 1, 2, 2, 1},
{1, -1, 1, 0, 1, 1, 2, -1}, {1, -1, 1, 0, 2, 0, 2, 1},
}
v... | Give a code snippet in #Go
A pentomino is a polyomino that consists of 5 squares. There are 12 pentomino shapes,
if you don't count rotations and reflections. Most pentominoes can form their own mirror image through
rotation, but some of them have to be flipped over.
I ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/GUI/Maximum_window_dimensions | GUI/Maximum window dimensions | The task is to determine the maximum height and width of a window that can fit within the physical display area of the screen without scrolling.
This is effectively the screen size (not the total desktop area, which could be bigger than the screen display area) in pixels minus any adjustments for window decorations an... | #BaCon | BaCon | OPTION GUI TRUE
PRAGMA GUI gtk3
FUNCTION Define_Window
LOCAL (*max)() = gtk_window_maximize TYPE void
LOCAL id
id = GUIDEFINE("{ type=WINDOW name=window }")
CALL GUIFN(id, "window", max)
RETURN id
ENDFUNCTION
SUB Print_Dimensions
LOCAL (*size)() = gtk_window_get_size TYPE void
LO... | Give a code snippet in #BaCon
The task is to determine the maximum height and width of a window that can fit within the physical display area of the screen without scrolling.
This is effectively the screen size (not the total desktop area, which could be bigger than the screen display area) in pixels minus any adjust... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Keyboard_input/Flush_the_keyboard_buffer | Keyboard input/Flush the keyboard buffer | Flush the keyboard buffer.
This reads characters from the keyboard input and
discards them until there are no more currently buffered,
and then allows the program to continue.
The program must not wait for users to type anything.
| #Bash | Bash | while read -t 0.01; do
true
done | Give a code snippet in #Bash
Flush the keyboard buffer.
This reads characters from the keyboard input and
discards them until there are no more currently buffered,
and then allows the program to continue.
The program must not wait for users to type anything.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Binary_strings | Binary strings | Many languages have powerful and useful (binary safe) string manipulation functions, while others don't, making it harder for these languages to accomplish some tasks.
This task is about creating functions to handle binary strings (strings made of arbitrary bytes, i.e. byte strings according to Wikipedia) for those la... | #BBC_BASIC | BBC BASIC | A$ = CHR$(0) + CHR$(1) + CHR$(254) + CHR$(255) : REM assignment
B$ = A$ : REM clone / copy
IF A$ = B$ THEN PRINT "Strings are equal" : REM comparison
IF A$ = "" THEN PRINT "String is empty" : REM Check if empty
A$ += CHR$(128) ... | Give a code snippet in #BBC_BASIC
Many languages have powerful and useful (binary safe) string manipulation functions, while others don't, making it harder for these languages to accomplish some tasks.
This task is about creating functions to handle binary strings (strings made of arbitrary bytes, i.e. byte strings a... | 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.
| #Tcl | Tcl | package require Tk
pack [label .l -text "There have been no clicks yet"]
set count 0
pack [button .b -text "click me" -command upd]
proc upd {} {
.l configure -text "Number of clicks: [incr ::count]"
} | Give a code snippet in #Tcl
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/Anagrams/Deranged_anagrams | Anagrams/Deranged anagrams | Two or more words are said to be anagrams if they have the same characters, but in a different order.
By analogy with derangements we define a deranged anagram as two words with the same characters, but in which the same character does not appear in the same position in both words.
Task[edit]
Use the word list at uni... | #C.23 | C# | public static void Main()
{
var lookupTable = File.ReadLines("unixdict.txt").ToLookup(line => AnagramKey(line));
var query = from a in lookupTable
orderby a.Key.Length descending
let deranged = FindDeranged(a)
where deranged != null
select deranged[0] + " " + deranged[1];
Con... | Give a code snippet in #C.23
Two or more words are said to be anagrams if they have the same characters, but in a different order.
By analogy with derangements we define a deranged anagram as two words with the same characters, but in which the same character does not appear in the same position in both words.
Task[... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Use_another_language_to_call_a_function | Use another language to call a function | This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
This task is inverse to the task Call foreign language function. Consider the following C program:
#include <stdio.h>
extern int Query (char * Data, size_t * Length);
int main (i... | #Haxe | Haxe | untyped __call__("functionName", args); | Give a code snippet in #Haxe
This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
This task is inverse to the task Call foreign language function. Consider the following C program:
#include <stdio.h>
extern int Query (char * Data, s... | christopher/rosetta-code | |
http://rosettacode.org/wiki/RSA_code | RSA code | Given an RSA key (n,e,d), construct a program to encrypt and decrypt plaintext messages strings.
Background
RSA code is used to encode secret messages. It is named after Ron Rivest, Adi Shamir, and Leonard Adleman who published it at MIT in 1977. The advantage of this type of encryption is that you can distribute the... | #Java | Java |
public static void main(String[] args) {
/*
This is probably not the best method...or even the most optimized way...however it works since n and d are too big to be ints or longs
This was also only tested with 'Rosetta Code' and 'Hello World'
It's also pretty limited on plainText size (anything bigger... | Give a code snippet in #Java
Given an RSA key (n,e,d), construct a program to encrypt and decrypt plaintext messages strings.
Background
RSA code is used to encode secret messages. It is named after Ron Rivest, Adi Shamir, and Leonard Adleman who published it at MIT in 1977. The advantage of this type of encryption ... | 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.
| #F.23 | F# | open System
let Repeat c f =
for _ in 1 .. c do
f()
let Hello _ =
printfn "Hello world"
[<EntryPoint>]
let main _ =
Repeat 3 Hello
0 // return an integer exit code | Give a code snippet in #F.23
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/Substring | Substring |
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 |... | #Crystal | Crystal | def substring_demo(string, n, m, known_character, known_substring)
n -= 1
puts string[n...n+m]
puts string[n...]
puts string.rchop
known_character_index = string.index(known_character).not_nil!
puts string[known_character_index...known_character_index+m]
known_substring_index = str... | Give a code snippet in #Crystal
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 Operation... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Send_email | Send email | Task
Write a function to send an email.
The function should have parameters for setting From, To and Cc addresses; the Subject, and the message text, and optionally fields for the server name and login details.
If appropriate, explain what notifications of problems/success are given.
Solutions using libraries or f... | #OCaml | OCaml | let h = Smtp.connect "smtp.gmail.fr";;
Smtp.helo h "hostname";;
Smtp.mail h "<john.smith@example.com>";;
Smtp.rcpt h "<john-doe@example.com>";;
let email_header = "\
From: John Smith <john.smith@example.com>
To: John Doe <john-doe@example.com>
Subject: surprise";;
let email_msg = "Happy Birthday";;
Smtp.data h (email_h... | Give a code snippet in #OCaml
Task
Write a function to send an email.
The function should have parameters for setting From, To and Cc addresses; the Subject, and the message text, and optionally fields for the server name and login details.
If appropriate, explain what notifications of problems/success are given.
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Equilibrium_index | Equilibrium index | An equilibrium index of a sequence is an index into the sequence such that the sum of elements at lower indices is equal to the sum of elements at higher indices.
For example, in a sequence
A
{\displaystyle A}
:
A
0
=
−
7
{\displaystyle A_{0}=-7}
A
1
=
1
{\displaystyle A_{1}=1}
... | #Ruby | Ruby | def eq_indices(list)
list.each_index.select do |i|
list[0...i].sum == list[i+1..-1].sum
end
end | Give a code snippet in #Ruby
An equilibrium index of a sequence is an index into the sequence such that the sum of elements at lower indices is equal to the sum of elements at higher indices.
For example, in a sequence
A
{\displaystyle A}
:
A
0
=
−
7
{\displaystyle A_{0}=-7}
A
1
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Pangram_checker | Pangram checker | Pangram checker
You are encouraged to solve this task according to the task description, using any language you may know.
A pangram is a sentence that contains all the letters of the English alphabet at least once.
For example: The quick brown fox jumps over the lazy dog.
Task
Write a function or method to chec... | #ALGOL_68 | ALGOL 68 | # init pangram: #
INT la = ABS "a", lz = ABS "z";
INT ua = ABS "A", uz = ABS "Z";
IF lz-la+1 > bits width THEN
put(stand error, "Exception: insufficient bits in word for task");
stop
FI;
PROC is a pangram = (STRING test)BOOL: (
BITS a2z := BIN(ABS(2r1 SHL (lz-la))-1); # assume: ASCII & Binary #
FOR i TO UPB t... | Give a code snippet in #ALGOL_68
Pangram checker
You are encouraged to solve this task according to the task description, using any language you may know.
A pangram is a sentence that contains all the letters of the English alphabet at least once.
For example: The quick brown fox jumps over the lazy dog.
Task
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Teacup_rim_text | Teacup rim text | On a set of coasters we have, there's a picture of a teacup. On the rim of the teacup the word TEA appears a number of times separated by bullet characters (•).
It occurred to me that if the bullet were removed and the words run together, you could start at any letter and still end up with a meaningful three... | #Go | Go | package main
import (
"bufio"
"fmt"
"log"
"os"
"sort"
"strings"
)
func check(err error) {
if err != nil {
log.Fatal(err)
}
}
func readWords(fileName string) []string {
file, err := os.Open(fileName)
check(err)
defer file.Close()
var words []string
scanne... | Give a code snippet in #Go
On a set of coasters we have, there's a picture of a teacup. On the rim of the teacup the word TEA appears a number of times separated by bullet characters (•).
It occurred to me that if the bullet were removed and the words run together, you could start at any letter and still en... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Self_numbers | Self numbers | A number n is a self number if there is no number g such that g + the sum of g's digits = n. So 18 is not a self number because 9+9=18, 43 is not a self number because 35+5+3=43.
The task is:
Display the first 50 self numbers;
I believe that the 100000000th self number is 1022727208. You should either confirm or d... | #jq | jq |
def sumdigits: tostring | explode | map([.]|implode|tonumber) | add;
def gsum: . + sumdigits;
def isnonself:
def ndigits: tostring|length;
. as $i
| ($i - ($i|ndigits)*9) as $n
| any( range($i-1; [0,$n]|max; -1);
gsum == $i);
# an array
def last81:
[limit(81; range(1; infinite) | select(isno... | Give a code snippet in #jq
A number n is a self number if there is no number g such that g + the sum of g's digits = n. So 18 is not a self number because 9+9=18, 43 is not a self number because 35+5+3=43.
The task is:
Display the first 50 self numbers;
I believe that the 100000000th self number is 1022727208. Yo... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Averages/Pythagorean_means | Averages/Pythagorean means | Task[edit]
Compute all three of the Pythagorean means of the set of integers 1 through 10 (inclusive).
Show that
A
(
x
1
,
…
,
x
n
)
≥
G
(
x
1
,
…
,
x
n
)
≥
H
(
x
1
,
…
,
x
n
)
{\displaystyle A(x_{1},\ldots ,x_{n})\geq G(x_{1},\ldots ,x_{n})\geq H(x_{1},\ldots ,x_{n})}
for this set of p... | #AWK | AWK | #!/usr/bin/awk -f
{
x = $1; # value of 1st column
A += x;
G += log(x);
H += 1/x;
N++;
}
END {
print "Arithmethic mean: ",A/N;
print "Geometric mean : ",exp(G/N);
print "Harmonic mean : ",N/H;
} | Give a code snippet in #AWK
Task[edit]
Compute all three of the Pythagorean means of the set of integers 1 through 10 (inclusive).
Show that
A
(
x
1
,
…
,
x
n
)
≥
G
(
x
1
,
…
,
x
n
)
≥
H
(
x
1
,
…
,
x
n
)
{\displaystyle A(x_{1},\ldots ,x_{n})\geq G(x_{1},\ldots ,x_{n})\geq H(x_{1},\ldots... | christopher/rosetta-code | |
http://rosettacode.org/wiki/System_time | System time | Task
Output the system time (any units will do as long as they are noted) either by a system command or one built into the language.
The system time can be used for debugging, network information, random number seeds, or something as simple as program performance.
Related task
Date format
See also
Retr... | #XPL0 | XPL0 | include c:\cxpl\codes; \include intrinsic 'code' declarations
proc NumOut(N); \Output a 2-digit number, including leading zero
int N;
[if N <= 9 then ChOut(0, ^0);
IntOut(0, N);
]; \NumOut
int Reg;
[Reg:= GetReg; \get address of array with copy of CPU registers
Reg(0):= $2... | Give a code snippet in #XPL0
Task
Output the system time (any units will do as long as they are noted) either by a system command or one built into the language.
The system time can be used for debugging, network information, random number seeds, or something as simple as program performance.
Related task
D... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Filter | Filter | Task
Select certain elements from an Array into a new Array in a generic way.
To demonstrate, select all even numbers from an Array.
As an option, give a second solution which filters destructively,
by modifying the original Array rather than creating a new Array.
| #AutoHotkey | AutoHotkey | array = 1,2,3,4,5,6,7
loop, parse, array, `,
{
if IsEven(A_LoopField)
evens = %evens%,%A_LoopField%
}
stringtrimleft, evens, evens, 1
msgbox % evens
return
IsEven(number)
{
return !mod(number, 2)
}
; ----- Another version: always with csv string ------
array = 1,2,3,4,5,6,7
even(s) {
loop, pars... | Give a code snippet in #AutoHotkey
Task
Select certain elements from an Array into a new Array in a generic way.
To demonstrate, select all even numbers from an Array.
As an option, give a second solution which filters destructively,
by modifying the original Array rather than creating a new Array.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Sorting_algorithms/Stooge_sort | Sorting algorithms/Stooge 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
... | #IS-BASIC | IS-BASIC | 100 PROGRAM "StoogSrt.bas"
110 RANDOMIZE
120 NUMERIC ARRAY(5 TO 16)
130 CALL INIT(ARRAY)
140 CALL WRITE(ARRAY)
150 CALL STOOGESORT(ARRAY,LBOUND(ARRAY),UBOUND(ARRAY))
160 CALL WRITE(ARRAY)
170 DEF INIT(REF A)
180 FOR I=LBOUND(A) TO UBOUND(A)
190 LET A(I)=RND(99)+1
200 NEXT
210 END DEF
220 DEF WRITE(REF A)
230 ... | Give a code snippet in #IS-BASIC
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/Read_a_file_character_by_character/UTF8 | Read a file character by character/UTF8 | Task
Read a file one character at a time, as opposed to reading the entire file at once.
The solution may be implemented as a procedure, which returns the next character in the file on each consecutive call (returning EOF when the end of the file is reached).
The procedure should support the reading of files contain... | #BASIC256 | BASIC256 | f = freefile
filename$ = "file.txt"
open f, filename$
while not eof(f)
print chr(readbyte(f));
end while
close f
end | Give a code snippet in #BASIC256
Task
Read a file one character at a time, as opposed to reading the entire file at once.
The solution may be implemented as a procedure, which returns the next character in the file on each consecutive call (returning EOF when the end of the file is reached).
The procedure should su... | 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 ... | #PureBasic | PureBasic | Procedure IsPalindrome(StringToTest.s)
If StringToTest=ReverseString(StringToTest)
ProcedureReturn 1
Else
ProcedureReturn 0
EndIf
EndProcedure | Give a code snippet in #PureBasic
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 (possibl... | christopher/rosetta-code | |
http://rosettacode.org/wiki/24_game | 24 game | The 24 Game tests one's mental arithmetic.
Task
Write a program that randomly chooses and displays four digits, each from 1 ──► 9 (inclusive) with repetitions allowed.
The program should prompt for the player to enter an arithmetic expression using just those, and all of those four digits, used exactly once each. T... | #Haskell | Haskell | import Data.List (sort)
import Data.Char (isDigit)
import Data.Maybe (fromJust)
import Control.Monad (foldM)
import System.Random (randomRs, getStdGen)
import System.IO (hSetBuffering, stdout, BufferMode(NoBuffering))
main = do
hSetBuffering stdout NoBuffering
mapM_
putStrLn
[ "THE 24 GAME\n"
, "Given... | Give a code snippet in #Haskell
The 24 Game tests one's mental arithmetic.
Task
Write a program that randomly chooses and displays four digits, each from 1 ──► 9 (inclusive) with repetitions allowed.
The program should prompt for the player to enter an arithmetic expression using just those, and all of those four ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Benford%27s_law | Benford's law |
This page uses content from Wikipedia. The original article was at Benford's_law. 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)
Benford's law, also called the first-digit law, refers to the freque... | #Groovy | Groovy | def tallyFirstDigits = { size, generator ->
def population = (0..<size).collect { generator(it) }
def firstDigits = [0]*10
population.each { number ->
firstDigits[(number as String)[0] as int] ++
}
firstDigits
} | Give a code snippet in #Groovy
This page uses content from Wikipedia. The original article was at Benford's_law. 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)
Benford's law, also called the first... | 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.
| #NetRexx | NetRexx | /* NetRexx */
options replace format comments java crossref savelog symbols binary
say "<?xml version='1.0' encoding='UTF-8' standalone='no'?>"
say "<!DOCTYPE svg PUBLIC '-//W3C//DTD SVG 1.1//EN'"
say " 'http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd'>"
say "<svg xmlns='http://www.w3.org/2000/svg' version='1.1'"... | Give a code snippet in #NetRexx
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/Empty_program | Empty program | Task
Create the simplest possible program that is still considered "correct."
| #SimpleCode | SimpleCode | Give a code snippet in #SimpleCode
Task
Create the simplest possible program that is still considered "correct."
| christopher/rosetta-code | ||
http://rosettacode.org/wiki/Split_a_character_string_based_on_change_of_character | Split a character string based on change of character |
Task
Split a (character) string into comma (plus a blank) delimited
strings based on a change of character (left to right).
Show the output here (use the 1st example below).
Blanks should be treated as any other character (except
they are problematic to display clearly). The same applies
to commas.
Fo... | #IS-BASIC | IS-BASIC | 100 LET S$="gHHH5YY++///\"
110 PRINT S$(1);
120 FOR I=2 TO LEN(S$)
130 IF S$(I)<>S$(I-1) THEN PRINT ", ";
140 PRINT S$(I);
150 NEXT
160 PRINT | Give a code snippet in #IS-BASIC
Task
Split a (character) string into comma (plus a blank) delimited
strings based on a change of character (left to right).
Show the output here (use the 1st example below).
Blanks should be treated as any other character (except
they are problematic to display clearly). ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Bitmap/Read_an_image_through_a_pipe | Bitmap/Read an image through a pipe | This task is the opposite of the PPM conversion through a pipe. In this task, using a delegate tool (like cjpeg, one of the netpbm package, or convert of the ImageMagick package) we read an image file and load it into the data storage type defined here. We can also use the code from Read ppm file, so that we can use PP... | #Wren | Wren | import "graphics" for Canvas, ImageData, Color
import "dome" for Window, Process
import "io" for FileSystem
import "plugin" for Plugin
Plugin.load("pipeconv")
import "pipeconv" for PipeConv
class Bitmap {
construct new(fileName, fileName2, fileName3, width, height) {
Window.title = "Bitmap - read imag... | Give a code snippet in #Wren
This task is the opposite of the PPM conversion through a pipe. In this task, using a delegate tool (like cjpeg, one of the netpbm package, or convert of the ImageMagick package) we read an image file and load it into the data storage type defined here. We can also use the code from Read p... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Create_a_two-dimensional_array_at_runtime | Create a two-dimensional array at runtime |
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.
Get two integers from the user, then create a two-dimensional array where the two dimensions have the sizes given by those numbers, and which can be accessed ... | #SNOBOL4 | SNOBOL4 | * # Get user X,Y dimensions
output = 'Enter X,Y:'; xy = trim(input)
xy break(',') . x ',' rem . y
* # Define and create array, 1-based
arr = array(x ',' y) ;* Or arr = array(xy)
* # Display array prototype
output = 'Prototype: ' prototype(arr)
* # Assign ele... | Give a code snippet in #SNOBOL4
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.
Get two integers from the user, then create a two-dimensional array where the two dimensions have the sizes given by those nu... | 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... | #D | D | import std.stdio, std.algorithm, std.array, std.string, std.range;
T pop(T)(ref T[] items, in size_t i) pure /*nothrow*/ @safe /*@nogc*/ {
auto aux = items[i];
items = items.remove(i);
return aux;
}
string josephus(in int n, in int k) pure /*nothrow*/ @safe {
auto p = n.iota.array;
int i;
im... | Give a code snippet in #D
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
{\disp... | christopher/rosetta-code | |
http://rosettacode.org/wiki/XML/Output | XML/Output | Create a function that takes a list of character names and a list of corresponding remarks and returns an XML document of <Character> elements each with a name attributes and each enclosing its remarks.
All <Character> elements are to be enclosed in turn, in an outer <CharacterRemarks> element.
As an example, calling ... | #Wren | Wren | var escapes = [
["&" , "&"], // must do this one first
["\"", """],
["'" , "'"],
["<" , "<"],
[">" , ">"]
]
var xmlEscape = Fn.new { |s|
for (esc in escapes) s = s.replace(esc[0], esc[1])
return s
}
var xmlDoc = Fn.new { |names, remarks|
var xml = "<CharacterRe... | Give a code snippet in #Wren
Create a function that takes a list of character names and a list of corresponding remarks and returns an XML document of <Character> elements each with a name attributes and each enclosing its remarks.
All <Character> elements are to be enclosed in turn, in an outer <CharacterRemarks> ele... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Compound_data_type | Compound data type |
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.
Task
Create a compound data type:
Point(x,y)
A compound data type is one that holds multiple independent values.
Related task
Enumeration
S... | #Erlang | Erlang |
-module(records_test).
-compile(export_all).
-record(point,{x,y}).
test() ->
P1 = #point{x=1.0,y=2.0}, % creates a new point record
io:fwrite("X: ~f, Y: ~f~n",[P1#point.x,P1#point.y]),
P2 = P1#point{x=3.0}, % creates a new point record with x set to 3.0, y is copied from P1
io:fwrite("X: ~f, Y: ~f... | Give a code snippet in #Erlang
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.
Task
Create a compound data type:
Point(x,y)
A compound data type is one that holds multiple independent values.
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Averages/Arithmetic_mean | Averages/Arithmetic mean | Task[edit]
Write a program to find the mean (arithmetic average) of a numeric vector.
In case of a zero-length input, since the mean of an empty set of numbers is ill-defined, the program may choose to behave in any way it deems appropriate, though if the programming language has an established convention for conveyin... | #Wren | Wren | class Arithmetic {
static mean(arr) {
if (arr.count == 0) Fiber.abort("Length must be greater than zero")
return arr.reduce(Fn.new{ |x,y| x+y }) / arr.count
}
}
Arithmetic.mean([1,2,3,4,5]) // 3 | Give a code snippet in #Wren
Task[edit]
Write a program to find the mean (arithmetic average) of a numeric vector.
In case of a zero-length input, since the mean of an empty set of numbers is ill-defined, the program may choose to behave in any way it deems appropriate, though if the programming language has an estab... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Averages/Pythagorean_means | Averages/Pythagorean means | Task[edit]
Compute all three of the Pythagorean means of the set of integers 1 through 10 (inclusive).
Show that
A
(
x
1
,
…
,
x
n
)
≥
G
(
x
1
,
…
,
x
n
)
≥
H
(
x
1
,
…
,
x
n
)
{\displaystyle A(x_{1},\ldots ,x_{n})\geq G(x_{1},\ldots ,x_{n})\geq H(x_{1},\ldots ,x_{n})}
for this set of p... | #Arturo | Arturo | arithmeticMean: function [arr]->
average arr
geometricMean: function [arr]->
(product arr) ^ 1//size arr
harmonicMean: function [arr]->
(size arr) // sum map arr 'i [1//i]
print arithmeticMean 1..10
print geometricMean 1..10
print harmonicMean 1..10 | Give a code snippet in #Arturo
Task[edit]
Compute all three of the Pythagorean means of the set of integers 1 through 10 (inclusive).
Show that
A
(
x
1
,
…
,
x
n
)
≥
G
(
x
1
,
…
,
x
n
)
≥
H
(
x
1
,
…
,
x
n
)
{\displaystyle A(x_{1},\ldots ,x_{n})\geq G(x_{1},\ldots ,x_{n})\geq H(x_{1},\ld... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Matrix_digital_rain | Matrix digital rain | Implement the Matrix Digital Rain visual effect from the movie "The Matrix" as described in Wikipedia.
Provided is a reference implementation in Common Lisp to be run in a terminal.
| #Raku | Raku | # clean up on exit, reset ANSI codes, scroll, re-show the cursor & clear screen
signal(SIGINT).tap: { print "\e[0m", "\n" xx 50, "\e[H\e[J\e[?25h"; exit(0) }
# a list of glyphs to use
my @codes = flat 'Α' .. 'Π', 'Ѐ' .. 'ѵ', 'Ҋ' .. 'ԯ', 'Ϣ' .. 'ϯ', 'ｦ'.. 'ﾝ',
'Ⲁ' .. '⳩', '∀' .. '∗', '℀' .. '℺', '⨀' .... | Give a code snippet in #Raku
Implement the Matrix Digital Rain visual effect from the movie "The Matrix" as described in Wikipedia.
Provided is a reference implementation in Common Lisp to be run in a terminal.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Number_reversal_game | Number reversal game | Task
Given a jumbled list of the numbers 1 to 9 that are definitely not in
ascending order.
Show the list, and then ask the player how many digits from the
left to reverse.
Reverse those digits, then ask again, until all the digits end up in ascending order.
The score is the count of the reversa... | #Factor | Factor | USING: formatting io kernel math math.parser math.ranges
namespaces random sequences strings ;
IN: rosetta.number-reversal
: make-jumbled-array ( -- sorted jumbled )
CHAR: 1 CHAR: 9 [a,b] [ 1string ] map dup clone randomize
[ 2dup = ] [ randomize ] while ;
SYMBOL: trials
: prompt ( jumbled -- n )
tria... | Give a code snippet in #Factor
Task
Given a jumbled list of the numbers 1 to 9 that are definitely not in
ascending order.
Show the list, and then ask the player how many digits from the
left to reverse.
Reverse those digits, then ask again, until all the digits end up in ascending order.
The s... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Even_or_odd | Even or odd | Task
Test whether an integer is even or odd.
There is more than one way to solve this task:
Use the even and odd predicates, if the language provides them.
Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd.
Divide i by 2. The remainder equals... | #Little_Man_Computer | Little Man Computer |
// Input number; output its residue mod 2
INP // read input into acc
BRZ write // input = 0 is special case
loop SUB k2 // keep subtracting 2 from acc
BRZ write // if acc = 0, input is even
BRP loop // if acc > 0, loop back
// (BRP branches if acc >= 0, b... | Give a code snippet in #Little_Man_Computer
Task
Test whether an integer is even or odd.
There is more than one way to solve this task:
Use the even and odd predicates, if the language provides them.
Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Parsing/RPN_calculator_algorithm | Parsing/RPN calculator algorithm | Task
Create a stack-based evaluator for an expression in reverse Polish notation (RPN) that also shows the changes in the stack as each individual token is processed as a table.
Assume an input of a correct, space separated, string of tokens of an RPN expression
Test with the RPN expression generated from the... | #Julia | Julia | function rpn(s)
stack = Any[]
for op in map(eval, map(parse, split(s)))
if isa(op, Function)
arg2 = pop!(stack)
arg1 = pop!(stack)
push!(stack, op(arg1, arg2))
else
push!(stack, op)
end
println("$op: ", join(stack, ", "))
end
... | Give a code snippet in #Julia
Task
Create a stack-based evaluator for an expression in reverse Polish notation (RPN) that also shows the changes in the stack as each individual token is processed as a table.
Assume an input of a correct, space separated, string of tokens of an RPN expression
Test with the RP... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Include_a_file | Include a file | Task
Demonstrate the language's ability to include source code from other files.
See Also
Compiler/Simple file inclusion pre processor
| #Common_Lisp | Common Lisp | (load "path/to/file") | Give a code snippet in #Common_Lisp
Task
Demonstrate the language's ability to include source code from other files.
See Also
Compiler/Simple file inclusion pre processor
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Recaman%27s_sequence | Recaman's sequence | The Recamán's sequence generates Natural numbers.
Starting from a(0)=0, the n'th term a(n), where n>0, is the previous term minus n i.e a(n) = a(n-1) - n but only if this is both positive and has not been previousely generated.
If the conditions don't hold then a(n) = a(n-1) + n.
Task
Generate and show here the... | #Java | Java | import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
public class RecamanSequence {
public static void main(String[] args) {
List<Integer> a = new ArrayList<>();
a.add(0);
Set<Integer> used = new HashSet<>();
used.add(0);
Se... | Give a code snippet in #Java
The Recamán's sequence generates Natural numbers.
Starting from a(0)=0, the n'th term a(n), where n>0, is the previous term minus n i.e a(n) = a(n-1) - n but only if this is both positive and has not been previousely generated.
If the conditions don't hold then a(n) = a(n-1) + n.
Tas... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Word_frequency | Word frequency | Task
Given a text file and an integer n, print/display the n most
common words in the file (and the number of their occurrences) in decreasing frequency.
For the purposes of this task:
A word is a sequence of one or more contiguous letters.
You are free to define what a letter is.
Undersc... | #VBA | VBA |
Option Explicit
Private Const PATHFILE As String = "C:\HOME\VBA\ROSETTA"
Sub Main()
Dim arr
Dim Dict As Object
Dim Book As String, temp As String
Dim T#
T = Timer
Book = ExtractTxt(PATHFILE & "\les miserables.txt")
temp = RemovePunctuation(Book)
temp = UCase(temp)
arr = Split(temp, " ")
Set Dict = ... | Give a code snippet in #VBA
Task
Given a text file and an integer n, print/display the n most
common words in the file (and the number of their occurrences) in decreasing frequency.
For the purposes of this task:
A word is a sequence of one or more contiguous letters.
You are free to define what... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Rename_a_file | Rename a file | Task
Rename:
a file called input.txt into output.txt and
a directory called docs into mydocs.
This should be done twice:
once "here", i.e. in the current working directory and once in the filesystem root.
It can be assumed that the user has the rights to do so.
(In unix-type s... | #Elixir | Elixir | File.rename "input.txt","output.txt"
File.rename "docs", "mydocs"
File.rename "/input.txt", "/output.txt"
File.rename "/docs", "/mydocs" | Give a code snippet in #Elixir
Task
Rename:
a file called input.txt into output.txt and
a directory called docs into mydocs.
This should be done twice:
once "here", i.e. in the current working directory and once in the filesystem root.
It can be assumed that the user has the r... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Canny_edge_detector | Canny edge detector | Task
Write a program that performs so-called canny edge detection on an image.
A possible algorithm consists of the following steps:
Noise reduction. May be performed by Gaussian filter.
Compute intensity gradient (matrices
G
x
{\displaystyle G_{x}}
and
G
y
{\displaystyle G_{y}}
) ... | #C | C | #include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <float.h>
#include <math.h>
#include <string.h>
#include <stdbool.h>
#include <assert.h>
#define MAX_BRIGHTNESS 255
// C99 doesn't define M_PI (GNU-C99 does)
#define M_PI 3.14159265358979323846264338327
/*
* Loading part taken from
* http://www... | Give a code snippet in #C
Task
Write a program that performs so-called canny edge detection on an image.
A possible algorithm consists of the following steps:
Noise reduction. May be performed by Gaussian filter.
Compute intensity gradient (matrices
G
x
{\displaystyle G_{x}}
and
G
y
... | 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... | #Racket | Racket |
#lang racket
;; Racket can use Unicode in identifier names
(define √ sqrt)
(√ 256) ; -> 16
;; and in fact the standard language makes use of some of these
(λ(x) x) ; -> an identity function
;; The required binding:
(define Δ 1)
(set! Δ (add1 Δ))
(printf "Δ = ~s\n" Δ) ; prints "Δ = 2"
| Give a code snippet in #Racket
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 tas... | christopher/rosetta-code | |
http://rosettacode.org/wiki/9_billion_names_of_God_the_integer | 9 billion names of God the integer | This task is a variation of the short story by Arthur C. Clarke.
(Solvers should be aware of the consequences of completing this task.)
In detail, to specify what is meant by a “name”:
The integer 1 has 1 name “1”.
The integer 2 has 2 names “1+1”, and “2”.
The integer 3 has 3 names “1+1+1”, “2+1”, ... | #PARI.2FGP | PARI/GP | row(n)=my(v=vector(n)); forpart(i=n,v[i[#i]]++); v;
show(n)=for(k=1,n,print(row(k)));
show(25)
apply(numbpart, [23,123,1234,12345])
plot(x=1,999.9, numbpart(x\1)) | Give a code snippet in #PARI.2FGP
This task is a variation of the short story by Arthur C. Clarke.
(Solvers should be aware of the consequences of completing this task.)
In detail, to specify what is meant by a “name”:
The integer 1 has 1 name “1”.
The integer 2 has 2 names “1+1”, and “2”.
The integer 3... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sleep | Sleep | Task
Write a program that does the following in this order:
Input an amount of time to sleep in whatever units are most natural for your language (milliseconds, seconds, ticks, etc.). This unit should be noted in comments or in a description.
Print "Sleeping..."
Sleep the main thread for the given amount of time.
... | #Eiffel | Eiffel | class
APPLICATION
inherit
EXECUTION_ENVIRONMENT
create
make
feature -- Initialization
make
-- Sleep for a given number of nanoseconds.
do
print ("Enter a number of nanoseconds: ")
io.read_integer_64
print ("Sleeping...%N")
sleep (io.las... | Give a code snippet in #Eiffel
Task
Write a program that does the following in this order:
Input an amount of time to sleep in whatever units are most natural for your language (milliseconds, seconds, ticks, etc.). This unit should be noted in comments or in a description.
Print "Sleeping..."
Sleep the main threa... | 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... | #Java | Java | public static String lookandsay(String number){
StringBuilder result= new StringBuilder();
char repeat= number.charAt(0);
number= number.substring(1) + " ";
int times= 1;
for(char actual: number.toCharArray()){
if(actual != repeat){
result.append(times + "" + repeat);
times= 1;
repeat= actual;
}el... | Give a code snippet in #Java
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 ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Echo_server | Echo server | Create a network service that sits on TCP port 12321, which accepts connections on that port, and which echoes complete lines (using a carriage-return/line-feed sequence as line separator) back to clients. No error handling is required. For the purposes of testing, it is only necessary to support connections from local... | #C | C | #include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <unistd.h>
#include <sys/wait.h>
#include <signal.h>
#define MAX_ENQUEUED 20
#define BUF_LEN 256
#define PORT_STR "12321"
/* --------------------------------------... | Give a code snippet in #C
Create a network service that sits on TCP port 12321, which accepts connections on that port, and which echoes complete lines (using a carriage-return/line-feed sequence as line separator) back to clients. No error handling is required. For the purposes of testing, it is only necessary to sup... | christopher/rosetta-code | |
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... | #Frink | Frink |
fakewidth =!= dummy
g = new graphics
g.antialiased[false]
drawBars[g, 0, 1, 0, 1/4, 8]
drawBars[g, 1, 0, 1/4, 1/2, 16]
drawBars[g, 0, 1, 1/2, 3/4, 32]
drawBars[g, 1, 0, 3/4, 1, 64]
g.show[640,480,1] // No portable fullscreen mode; user must maximize window.
drawBars[g is graphics, leftColor, rightColor, top, bot... | Give a code snippet in #Frink
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 h... | 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... | #8086_Assembly | 8086 Assembly |
\ Array of doors; init to empty; accessing a non-extant member will return
\ 'null', which is treated as 'false', so we don't need to initialize it:
[] var, doors
\ given a door number, get the value and toggle it:
: toggle-door \ n --
doors @ over a:@
not rot swap a:! drop ;
\ print which doors are open:
:... | Give a code snippet in #8086_Assembly
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... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sort_a_list_of_object_identifiers | Sort a list of object identifiers |
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
... | #Phix | Phix | sequence strings = {"1.3.6.1.4.1.11.2.17.19.3.4.0.10",
"1.3.6.1.4.1.11.2.17.5.2.0.79",
"1.3.6.1.4.1.11.2.17.19.3.4.0.4",
"1.3.6.1.4.1.11150.3.4.0.1",
"1.3.6.1.4.1.11.2.17.19.3.4.0.1",
"1.3.6.1.4.1.11150.3.4.0"}
constan... | Give a code snippet in #Phix
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 sor... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Cholesky_decomposition | Cholesky decomposition | Every symmetric, positive definite matrix A can be decomposed into a product of a unique lower triangular matrix L and its transpose:
A
=
L
L
T
{\displaystyle A=LL^{T}}
L
{\displaystyle L}
is called the Cholesky factor of
A
{\displaystyle A}
, and can be interpreted as a generalized square r... | #Lobster | Lobster | import std
// choleskyLower returns the cholesky decomposition of a symmetric real
// matrix. The matrix must be positive definite but this is not checked
def choleskyLower(order, a) -> [float]:
let l = map(a.length): 0.0
var row, col = 1, 1
var dr = 0 // index of diagonal element at end of row
var d... | Give a code snippet in #Lobster
Every symmetric, positive definite matrix A can be decomposed into a product of a unique lower triangular matrix L and its transpose:
A
=
L
L
T
{\displaystyle A=LL^{T}}
L
{\displaystyle L}
is called the Cholesky factor of
A
{\displaystyle A}
, and can be inte... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Increment_a_numerical_string | Increment a numerical string | Task
Increment a numerical string.
| #HolyC | HolyC | I8 *s;
s = "10";
s = Str2I64(s) + 1;
Print("%d\n", s);
s = "-10";
s = Str2I64(s) + 1;
Print("%d\n", s); | Give a code snippet in #HolyC
Task
Increment a numerical string.
| 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 ... | #PHP | PHP | function multiply( $a, $b )
{
return $a * $b;
} | Give a code snippet in #PHP
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 fr... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Bioinformatics/base_count | Bioinformatics/base count | Given this string representing ordered DNA bases:
CGTAAAAAATTACAACGTCCTTTGGCTATCTCTTAAACTCCTGCTAAATG
CTCGTGCTTTCCAATTATGTAAGCGTTCCGAGACGGGGTGGTCGATTCTG
AGGACAAAGGTCAAGATGGAGCGCATCGAACGCAATAAGGATCATTTGAT
GGGACGTTTCGTCGACAAAGTCTTGTTTCGAGAGTAACGGCTACCGTCTT
CGATTCTGCTTATAACACTATGTTCTTATGAAATGGATGTTCTGAGTTGG
TCAGTCCCAATGTG... | #Tcl | Tcl | namespace path ::tcl::mathop
proc process {data {width 50}} {
set len [string length $data]
set addrwidth [string length [* [/ $len $width] $width]]
for {set i 0} {$i < $len} {incr i $width} {
puts "[format %${addrwidth}u $i] [string range $data $i $i+[- $width 1]]"
}
puts "\nBase count:"
foreach base {A C G ... | Give a code snippet in #Tcl
Given this string representing ordered DNA bases:
CGTAAAAAATTACAACGTCCTTTGGCTATCTCTTAAACTCCTGCTAAATG
CTCGTGCTTTCCAATTATGTAAGCGTTCCGAGACGGGGTGGTCGATTCTG
AGGACAAAGGTCAAGATGGAGCGCATCGAACGCAATAAGGATCATTTGAT
GGGACGTTTCGTCGACAAAGTCTTGTTTCGAGAGTAACGGCTACCGTCTT
CGATTCTGCTTATAACACTATGTTCTTATGAAATGG... | christopher/rosetta-code |
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