task_url stringlengths 30 116 | task_name stringlengths 2 86 | task_description stringlengths 0 14.4k | language_url stringlengths 2 53 | language_name stringlengths 1 52 | code stringlengths 0 61.9k | response_seed stringclasses 1
value | instruction_seed stringlengths 27 14.4k | _source stringclasses 1
value |
|---|---|---|---|---|---|---|---|---|
http://rosettacode.org/wiki/Damm_algorithm | Damm algorithm | The Damm algorithm is a checksum algorithm which detects all single digit errors and adjacent transposition errors.
The algorithm is named after H. Michael Damm.
Task
Verify the checksum, stored as last digit of an input.
| #Python | Python | def damm(num: int) -> bool:
row = 0
for digit in str(num):
row = _matrix[row][int(digit)]
return row == 0
_matrix = (
(0, 3, 1, 7, 5, 9, 8, 6, 4, 2),
(7, 0, 9, 2, 1, 5, 4, 8, 6, 3),
(4, 2, 0, 6, 8, 7, 1, 3, 5, 9),
(1, 7, 5, 0, 9, 8, 3, 4, 2, 6),
(6, 1, 2, 3, 0, 4, 5, 9, 7, 8),... | Give a code snippet in #Python
The Damm algorithm is a checksum algorithm which detects all single digit errors and adjacent transposition errors.
The algorithm is named after H. Michael Damm.
Task
Verify the checksum, stored as last digit of an input.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow ... | #AWK | AWK | $ awk 'func fib(n){return(n<2?n:fib(n-1)+fib(n-2))}{print "fib("$1")="fib($1)}'
10
fib(10)=55 | Give a code snippet in #AWK
The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are g... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Show_the_epoch | Show the epoch | Task
Choose popular date libraries used by your language and show the epoch those libraries use.
A demonstration is preferable (e.g. setting the internal representation of the date to 0 ms/ns/etc., or another way that will still show the epoch even if it is changed behind the scenes by the implementers), b... | #C | C | #include <time.h>
#include <stdio.h>
int main() {
time_t t = 0;
printf("%s", asctime(gmtime(&t)));
return 0;
} | Give a code snippet in #C
Task
Choose popular date libraries used by your language and show the epoch those libraries use.
A demonstration is preferable (e.g. setting the internal representation of the date to 0 ms/ns/etc., or another way that will still show the epoch even if it is changed behind the scene... | 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.
| #Julia | Julia | function sayHi()
println("Hi")
end
function rep(f, n)
for i = 1:n f() end
end
rep(sayHi, 3) | Give a code snippet in #Julia
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/Closest-pair_problem | Closest-pair problem |
This page uses content from Wikipedia. The original article was at Closest pair of points problem. 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)
Task
Provide a function to find the closest two p... | #FreeBASIC | FreeBASIC |
Dim As Integer i, j
Dim As Double minDist = 1^30
Dim As Double x(9), y(9), dist, mini, minj
Data 0.654682, 0.925557
Data 0.409382, 0.619391
Data 0.891663, 0.888594
Data 0.716629, 0.996200
Data 0.477721, 0.946355
Data 0.925092, 0.818220
Data 0.624291, 0.142924
Data 0.211332, 0.221507
Data 0.293786, 0.691701... | Give a code snippet in #FreeBASIC
This page uses content from Wikipedia. The original article was at Closest pair of points problem. 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)
Task
Provide a... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Extend_your_language | Extend your language | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Some programming languages allow you to extend the language. While this can be done to a certain degree in most languages (e.g. by using macros), other langua... | #Sidef | Sidef | class if2(cond1, cond2) {
method then(block) { # both true
if (cond1 && cond2) {
block.run;
}
return self;
}
method else1(block) { # first true
if (cond1 && !cond2) {
block.run;
}
return self;
}
method else2(block) { # se... | Give a code snippet in #Sidef
Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Some programming languages allow you to extend the language. While this can be done to a certain degree in most languages (e.g.... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Real_constants_and_functions | Real constants and functions | Task
Show how to use the following math constants and functions in your language (if not available, note it):
e (base of the natural logarithm)
π
{\displaystyle \pi }
square root
logarithm (any base allowed)
exponential (ex )
absolute value (a.k.a. "magnitude")
floor (largest ... | #Maple | Maple | > abs(ceil(floor(ln(exp(1)^sqrt(exp(Pi*I)+1)))));
0 | Give a code snippet in #Maple
Task
Show how to use the following math constants and functions in your language (if not available, note it):
e (base of the natural logarithm)
π
{\displaystyle \pi }
square root
logarithm (any base allowed)
exponential (ex )
absolute value (a.k.a. "m... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Terminal_control/Positional_read | Terminal control/Positional read | Determine the character displayed on the screen at column 3, row 6 and store that character in a variable. Note that it is permissible to utilize system or language provided methods or system provided facilities, system maintained records or available buffers or system maintained display records to achieve this task, r... | #Wren | Wren | /* terminal_control_positional_read.wren */
import "random" for Random
foreign class Window {
construct initscr() {}
foreign addstr(str)
foreign inch(y, x)
foreign move(y, x)
foreign refresh()
foreign getch()
foreign delwin()
}
class Ncurses {
foreign static endwin()
}
... | Give a code snippet in #Wren
Determine the character displayed on the screen at column 3, row 6 and store that character in a variable. Note that it is permissible to utilize system or language provided methods or system provided facilities, system maintained records or available buffers or system maintained display r... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Draw_a_pixel | Draw a pixel | Task
Create a window and draw a pixel in it, subject to the following:
the window is 320 x 240
the color of the pixel must be red (255,0,0)
the position of the pixel is x = 100, y = 100 | #Racket | Racket | #lang racket
(require racket/draw)
(let ((b (make-object bitmap% 320 240)))
(send b set-argb-pixels 100 100 1 1 (bytes 255 0 0 255))
b) | Give a code snippet in #Racket
Task
Create a window and draw a pixel in it, subject to the following:
the window is 320 x 240
the color of the pixel must be red (255,0,0)
the position of the pixel is x = 100, y = 100 | christopher/rosetta-code | |
http://rosettacode.org/wiki/Bitwise_operations | Bitwise operations |
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 |... | #Pike | Pike |
void bitwise(int a, int b)
{
write("a and b: %d\n", a & b);
write("a or b: %d\n", a | b);
write("a xor b: %d\n", a ^ b);
write("not a: %d\n", ~a);
write("a << b: 0x%x\n", a << b);
write("a >> b: %d\n", a >> b);
// ints in Pike do not overflow, if a particular size of the int
// is... | Give a code snippet in #Pike
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
C... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sum_and_product_puzzle | Sum and product puzzle | Task[edit]
Solve the "Impossible Puzzle":
X and Y are two different whole numbers greater than 1. Their sum is no greater than 100, and Y is greater than X. S and P are two mathematicians (and consequently perfect logicians); S knows the sum X+Y and P knows the product X*Y. Both S and P know all the information in th... | #Haskell | Haskell | import Data.List (intersect)
s1, s2, s3, s4 :: [(Int, Int)]
s1 = [(x, y) | x <- [1 .. 100], y <- [1 .. 100], 1 < x && x < y && x + y < 100]
add, mul :: (Int, Int) -> Int
add (x, y) = x + y
mul (x, y) = x * y
sumEq, mulEq :: (Int, Int) -> [(Int, Int)]
sumEq p = filter (\q -> add q == add p) s1
mulEq p = filter (\q... | Give a code snippet in #Haskell
Task[edit]
Solve the "Impossible Puzzle":
X and Y are two different whole numbers greater than 1. Their sum is no greater than 100, and Y is greater than X. S and P are two mathematicians (and consequently perfect logicians); S knows the sum X+Y and P knows the product X*Y. Both S and... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Evaluate_binomial_coefficients | Evaluate binomial coefficients | This programming task, is to calculate ANY binomial coefficient.
However, it has to be able to output
(
5
3
)
{\displaystyle {\binom {5}{3}}}
, which is 10.
This formula is recommended:
(
n
k
)
=
n
!
(
n
−
k
)
!
k
!
=
n
(
n
−
1
)
(
n
−
2
)
…
(
n
−
k
+
1
)
k
(
k
−
1... | #Erlang | Erlang |
choose(N, 0) -> 1;
choose(N, K) when is_integer(N), is_integer(K), (N >= 0), (K >= 0), (N >= K) ->
choose(N, K, 1, 1).
choose(N, K, K, Acc) ->
(Acc * (N-K+1)) div K;
choose(N, K, I, Acc) ->
choose(N, K, I+1, (Acc * (N-I+1)) div I).
| Give a code snippet in #Erlang
This programming task, is to calculate ANY binomial coefficient.
However, it has to be able to output
(
5
3
)
{\displaystyle {\binom {5}{3}}}
, which is 10.
This formula is recommended:
(
n
k
)
=
n
!
(
n
−
k
)
!
k
!
=
n
(
n
−
1
)
(
n
−... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Evaluate_binomial_coefficients | Evaluate binomial coefficients | This programming task, is to calculate ANY binomial coefficient.
However, it has to be able to output
(
5
3
)
{\displaystyle {\binom {5}{3}}}
, which is 10.
This formula is recommended:
(
n
k
)
=
n
!
(
n
−
k
)
!
k
!
=
n
(
n
−
1
)
(
n
−
2
)
…
(
n
−
k
+
1
)
k
(
k
−
1... | #PureBasic | PureBasic | Procedure Factor(n)
Protected Result=1
While n>0
Result*n
n-1
Wend
ProcedureReturn Result
EndProcedure
Macro C(n,k)
(Factor(n)/(Factor(k)*factor(n-k)))
EndMacro
If OpenConsole()
Print("Enter value n: "): n=Val(Input())
Print("Enter value k: "): k=Val(Input())
PrintN("C(n,k)= "+str(C(n,k)))
... | Give a code snippet in #PureBasic
This programming task, is to calculate ANY binomial coefficient.
However, it has to be able to output
(
5
3
)
{\displaystyle {\binom {5}{3}}}
, which is 10.
This formula is recommended:
(
n
k
)
=
n
!
(
n
−
k
)
!
k
!
=
n
(
n
−
1
)
(
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sum_of_a_series | Sum of a series | Compute the nth term of a series, i.e. the sum of the n first terms of the corresponding sequence.
Informally this value, or its limit when n tends to infinity, is also called the sum of the series, thus the title of this task.
For this task, use:
S
n
=
∑
k
=
1
n
1
k
2
{\displa... | #Vlang | Vlang | import math
fn main(){
println('known: ${math.pi*math.pi/6}')
mut sum := f64(0)
for i :=1e3; i >0; i-- {
sum += 1/(i*i)
}
println('computed: $sum')
} | Give a code snippet in #Vlang
Compute the nth term of a series, i.e. the sum of the n first terms of the corresponding sequence.
Informally this value, or its limit when n tends to infinity, is also called the sum of the series, thus the title of this task.
For this task, use:
S
n
=
∑
k
=
1... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Regular_expressions | Regular expressions |
Task
match a string against a regular expression
substitute part of a string using a regular expression
| #Kotlin | Kotlin | // version 1.0.6
fun main(args: Array<String>) {
val s1 = "I am the original string"
val r1 = Regex("^.*string$")
if (s1.matches(r1)) println("`$s1` matches `$r1`")
val r2 = Regex("original")
val s3 = "replacement"
val s2 = s1.replace(r2, s3)
if (s2 != s1) println("`$s2` replaces `$r2` wit... | Give a code snippet in #Kotlin
Task
match a string against a regular expression
substitute part of a string using a regular expression
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Append_a_record_to_the_end_of_a_text_file | Append a record to the end of a text file | Many systems offer the ability to open a file for writing, such that any data written will be appended to the end of the file. Further, the file operations will always adjust the position pointer to guarantee the end of the file, even in a multitasking environment.
This feature is most useful in the case of log files,... | #RapidQ | RapidQ |
'Short solution: Append record and read last record
$Include "Rapidq.inc"
dim file as qfilestream
dim filename as string
dim LogRec as string
'First create our logfile
filename = "C:\Logfile2.txt"
file.open(filename, fmCreate)
file.writeline "jsmith:x:1001:1000:Joe Smith,Room 1007,(234)555-8917,(234)555-0077,jsmi... | Give a code snippet in #RapidQ
Many systems offer the ability to open a file for writing, such that any data written will be appended to the end of the file. Further, the file operations will always adjust the position pointer to guarantee the end of the file, even in a multitasking environment.
This feature is most ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/String_append | String append |
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 |... | #GlovePIE | GlovePIE | var.string="This is "
var.string+="Sparta!"
debug=var.string | Give a code snippet in #GlovePIE
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 Operatio... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Strong_and_weak_primes | Strong and weak primes |
Definitions (as per number theory)
The prime(p) is the pth prime.
prime(1) is 2
prime(4) is 7
A strong prime is when prime(p) is > [prime(p-1) + prime(p+1)] ÷ 2
A weak prime is when prime(p) is < [prime(p-1) + prime(p+1)] ÷ 2
Note that the defin... | #Lua | Lua | -- Return a table of the primes up to n, then one more
function primeList (n)
local function isPrime (x)
for d = 3, math.sqrt(x), 2 do
if x % d == 0 then return false end
end
return true
end
local pTable, j = {2, 3}
for i = 5, n, 2 do
if isPrime(i) then
table.insert(pTable, i)
en... | Give a code snippet in #Lua
Definitions (as per number theory)
The prime(p) is the pth prime.
prime(1) is 2
prime(4) is 7
A strong prime is when prime(p) is > [prime(p-1) + prime(p+1)] ÷ 2
A weak prime is when prime(p) is < [prime(p-1) + prime(p+... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Exceptions/Catch_an_exception_thrown_in_a_nested_call | Exceptions/Catch an exception thrown in a nested call | Show how to create a user-defined exception and show how to catch an exception raised from several nested calls away.
Create two user-defined exceptions, U0 and U1.
Have function foo call function bar twice.
Have function bar call function baz.
Arrange for function baz to rais... | #Tcl | Tcl | package require Tcl 8.5
proc foo {} {
set code [catch {bar} ex options]
if {$code == 1} {
switch -exact -- $ex {
U0 {puts "caught exception U0"}
default {return -options $options $ex ;# re-raise exception}
}
}
}
proc bar {} {baz}
# create an alias to pass ... | Give a code snippet in #Tcl
Show how to create a user-defined exception and show how to catch an exception raised from several nested calls away.
Create two user-defined exceptions, U0 and U1.
Have function foo call function bar twice.
Have function bar call function baz.
Arrange... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Kernighans_large_earthquake_problem | Kernighans large earthquake problem | Brian Kernighan, in a lecture at the University of Nottingham, described a problem on which this task is based.
Problem
You are given a a data file of thousands of lines; each of three `whitespace` separated fields: a date, a one word name and the magnitude of the event.
Example lines from the file would be lines li... | #JavaScript | JavaScript |
const fs = require("fs");
const readline = require("readline");
const args = process.argv.slice(2);
if (!args.length) {
console.error("must supply file name");
process.exit(1);
}
const fname = args[0];
const readInterface = readline.createInterface({
input: fs.createReadStream(fname),
console: f... | Give a code snippet in #JavaScript
Brian Kernighan, in a lecture at the University of Nottingham, described a problem on which this task is based.
Problem
You are given a a data file of thousands of lines; each of three `whitespace` separated fields: a date, a one word name and the magnitude of the event.
Example l... | christopher/rosetta-code | |
http://rosettacode.org/wiki/99_bottles_of_beer | 99 bottles of beer | Task
Display the complete lyrics for the song: 99 Bottles of Beer on the Wall.
The beer song
The lyrics follow this form:
99 bottles of beer on the wall
99 bottles of beer
Take one down, pass it around
98 bottles of beer on the wall
98 bottles of beer on the wall
98 bottles of beer
Take one dow... | #Chef | Chef |
execute() {
// this class provides synchronization
// to get unique number of the bottle
class monitor giver {
int number = 100;
.get() { return --number; }
}
var g = new giver();
// start 99 concurrently worked threads
// each thread gets own number of the... | Give a code snippet in #Chef
Task
Display the complete lyrics for the song: 99 Bottles of Beer on the Wall.
The beer song
The lyrics follow this form:
99 bottles of beer on the wall
99 bottles of beer
Take one down, pass it around
98 bottles of beer on the wall
98 bottles of beer on the wall
98 ... | 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.
| #OCaml | OCaml | open Graphics
let draw_yinyang x y radius black white =
let hr = radius / 2 in
let sr = radius / 6 in
set_color black;
set_line_width 6;
draw_circle x y radius;
set_line_width 0;
set_color black;
fill_arc x y radius radius 270 450;
set_color white;
fill_arc x y radius radius 90 270;
fill_arc x (... | Give a code snippet in #OCaml
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/Environment_variables | Environment variables | Task
Show how to get one of your process's environment variables.
The available variables vary by system; some of the common ones available on Unix include:
PATH
HOME
USER
| #Maple | Maple | getenv("PATH"); | Give a code snippet in #Maple
Task
Show how to get one of your process's environment variables.
The available variables vary by system; some of the common ones available on Unix include:
PATH
HOME
USER
| christopher/rosetta-code | |
http://rosettacode.org/wiki/A%2BB | A+B | A+B ─── a classic problem in programming contests, it's given so contestants can gain familiarity with the online judging system being used.
Task
Given two integers, A and B.
Their sum needs to be calculated.
Input data
Two integers are written in the input stream, separated by space(s):
(
−
1000
≤... | #Component_Pascal | Component Pascal |
MODULE AB;
IMPORT StdLog, DevCommanders,TextMappers;
PROCEDURE DoAB(x,y: INTEGER);
BEGIN
StdLog.Int(x);StdLog.Int(y);StdLog.Int(x + y);StdLog.Ln;
END DoAB;
PROCEDURE Go*;
VAR
params: DevCommanders.Par;
s: TextMappers.Scanner;
p : ARRAY 2 OF INTEGER;
... | Give a code snippet in #Component_Pascal
A+B ─── a classic problem in programming contests, it's given so contestants can gain familiarity with the online judging system being used.
Task
Given two integers, A and B.
Their sum needs to be calculated.
Input data
Two integers are written in the input strea... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Walk_a_directory/Non-recursively | Walk a directory/Non-recursively | Task
Walk a given directory and print the names of files matching a given pattern.
(How is "pattern" defined? substring match? DOS pattern? BASH pattern? ZSH pattern? Perl regular expression?)
Note: This task is for non-recursive methods. These tasks should read a single directory, not an entire directory tree.
... | #Sidef | Sidef | '*.p[lm]'.glob.each { |file| say file } # Perl files under this directory | Give a code snippet in #Sidef
Task
Walk a given directory and print the names of files matching a given pattern.
(How is "pattern" defined? substring match? DOS pattern? BASH pattern? ZSH pattern? Perl regular expression?)
Note: This task is for non-recursive methods. These tasks should read a single directory, ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Anti-primes | Anti-primes | The anti-primes
(or highly composite numbers, sequence A002182 in the OEIS)
are the natural numbers with more factors than any smaller than itself.
Task
Generate and show here, the first twenty anti-primes.
Related tasks
Factors of an integer
Sieve of Eratosthenes
| #Java | Java | public class Antiprime {
static int countDivisors(int n) {
if (n < 2) return 1;
int count = 2; // 1 and n
for (int i = 2; i <= n/2; ++i) {
if (n%i == 0) ++count;
}
return count;
}
public static void main(String[] args) {
int maxDiv = 0, count =... | Give a code snippet in #Java
The anti-primes
(or highly composite numbers, sequence A002182 in the OEIS)
are the natural numbers with more factors than any smaller than itself.
Task
Generate and show here, the first twenty anti-primes.
Related tasks
Factors of an integer
Sieve of Eratosthenes
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Hello_world/Web_server | Hello world/Web server | The browser is the new GUI !
Task
Serve our standard text Goodbye, World! to http://localhost:8080/ so that it can be viewed with a web browser.
The provided solution must start or implement a server that accepts multiple client connections and serves text as requested.
Note that starting a web browser or... | #Dylan.NET | Dylan.NET |
//compile with dylan.NET 11.5.1.2 or later!!
#refstdasm "mscorlib.dll"
#refstdasm "System.dll"
import System.Text
import System.Net.Sockets
import System.Net
assembly helloweb exe
ver 1.1.0.0
namespace WebServer
class public GoodByeWorld
method public static void main(var args as string[])
... | Give a code snippet in #Dylan.NET
The browser is the new GUI !
Task
Serve our standard text Goodbye, World! to http://localhost:8080/ so that it can be viewed with a web browser.
The provided solution must start or implement a server that accepts multiple client connections and serves text as requested.
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Entropy/Narcissist | Entropy/Narcissist |
Task
Write a computer program that computes and shows its own entropy.
Related Tasks
Fibonacci_word
Entropy
| #Rust | Rust | use std::fs::File;
use std::io::{Read, BufReader};
fn entropy<I: IntoIterator<Item = u8>>(iter: I) -> f32 {
let mut histogram = [0u64; 256];
let mut len = 0u64;
for b in iter {
histogram[b as usize] += 1;
len += 1;
}
histogram
.iter()
.cloned()
.filter(|... | Give a code snippet in #Rust
Task
Write a computer program that computes and shows its own entropy.
Related Tasks
Fibonacci_word
Entropy
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/While | Loops/While | Task
Start an integer value at 1024.
Loop while it is greater than zero.
Print the value (with a newline) and divide it by two each time through the loop.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downward for
Loops/For
Loops/For... | #Scala | Scala | var i = 1024
while (i > 0) {
println(i)
i /= 2
} | Give a code snippet in #Scala
Task
Start an integer value at 1024.
Loop while it is greater than zero.
Print the value (with a newline) and divide it by two each time through the loop.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downwar... | 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... | #E | E | def makeColor(name :String) {
def color {
to colorize(thing :String) {
return `$name $thing`
}
}
return color
} | Give a code snippet in #E
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.
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Update_a_configuration_file | Update a configuration file | We have a configuration file as follows:
# This is a configuration file in standard configuration file format
#
# Lines begininning with a hash or a semicolon are ignored by the application
# program. Blank lines are also ignored by the application program.
# The first word on each non comment line is the configurati... | #C | C | #include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define strcomp(X, Y) strcasecmp(X, Y)
struct option
{ const char *name, *value;
int flag; };
/* TODO: dynamically obtain these */
struct option updlist[] =
{ { "NEEDSPEELING", NULL },
{ "SEEDSREMOVED", "" },
{ "NUMBEROFBANANAS", "1024" },
{ "NUM... | Give a code snippet in #C
We have a configuration file as follows:
# This is a configuration file in standard configuration file format
#
# Lines begininning with a hash or a semicolon are ignored by the application
# program. Blank lines are also ignored by the application program.
# The first word on each non comm... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Lychrel_numbers | Lychrel numbers | Take an integer n, greater than zero.
Form the next n of its series by reversing the digits of the current n and adding the result to the current n.
Stop when n becomes palindromic - i.e. the digits of n in reverse order == n.
The above recurrence relation when applied to most starting numbers n = 1, 2, ... ... | #R | R |
library(gmp)
library(magrittr)
cache <- NULL
cache_reset <- function() { cache <<- new.env(TRUE, emptyenv()) }
cache_set <- function(key, value) { assign(key, value, envir = cache) }
cache_get <- function(key) { get(key, envir = cache, inherits = FALSE) }
cache_has_key <- function(key) { exists(key, envir = cache... | Give a code snippet in #R
Take an integer n, greater than zero.
Form the next n of its series by reversing the digits of the current n and adding the result to the current n.
Stop when n becomes palindromic - i.e. the digits of n in reverse order == n.
The above recurrence relation when applied to most star... | christopher/rosetta-code | |
http://rosettacode.org/wiki/CRC-32 | CRC-32 |
Task
Demonstrate a method of deriving the Cyclic Redundancy Check from within the language.
The result should be in accordance with ISO 3309, ITU-T V.42, Gzip and PNG.
Algorithms are described on Computation of CRC in Wikipedia.
This variant of CRC-32 uses LSB-first order, sets the initial CRC to FFFFFFFF16, and... | #Ada | Ada | with Ada.Text_IO; use Ada.Text_IO;
with GNAT.CRC32; use GNAT.CRC32;
with Interfaces; use Interfaces;
procedure TestCRC is
package IIO is new Ada.Text_IO.Modular_IO (Unsigned_32);
crc : CRC32;
num : Unsigned_32;
str : String := "The quick brown fox jumps over the lazy dog";
begin
Initialize (crc);
Upda... | Give a code snippet in #Ada
Task
Demonstrate a method of deriving the Cyclic Redundancy Check from within the language.
The result should be in accordance with ISO 3309, ITU-T V.42, Gzip and PNG.
Algorithms are described on Computation of CRC in Wikipedia.
This variant of CRC-32 uses LSB-first order, sets the i... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Polyspiral | Polyspiral | A Polyspiral is a spiral made of multiple line segments, whereby each segment is larger (or smaller) than the previous one by a given amount. Each segment also changes direction at a given angle.
Task
Animate a series of polyspirals, by drawing a complete spiral then incrementing the angle, and (after clearing the b... | #Gnuplot | Gnuplot |
## plotpoly.gp 1/10/17 aev
## Plotting a polyspiral and writing to the png-file.
## Note: assign variables: rng, d, clr, filename and ttl (before using load command).
## Direction d (-1 clockwise / 1 counter-clockwise)
reset
set terminal png font arial 12 size 640,640
ofn=filename.".png"
set output ofn
unset border;... | Give a code snippet in #Gnuplot
A Polyspiral is a spiral made of multiple line segments, whereby each segment is larger (or smaller) than the previous one by a given amount. Each segment also changes direction at a given angle.
Task
Animate a series of polyspirals, by drawing a complete spiral then incrementing the... | 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... | #Simula | Simula |
BEGIN
PROCEDURE OUTOCT(N); INTEGER N;
BEGIN
PROCEDURE OCT(N); INTEGER N;
BEGIN
IF N > 0 THEN BEGIN
OCT(N//8);
OUTCHAR(CHAR(RANK('0')+MOD(N,8)));
END;
END OCT;
IF N < 0 THEN BEGIN OUTCHAR('-'); OUTOCT(-N); END
ELS... | Give a code snippet in #Simula
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.
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Maximum_triangle_path_sum | Maximum triangle path sum | Starting from the top of a pyramid of numbers like this, you can walk down going one step on the right or on the left, until you reach the bottom row:
55
94 48
95 30 96
77 71 26 67
One of such walks is 55 - 94 - 30 - 26.
You... | #C | C |
#include <stdio.h>
#include <math.h>
#define max(x,y) ((x) > (y) ? (x) : (y))
int tri[] = {
55,
94, 48,
95, 30, 96,
77, 71, 26, 67,
97, 13, 76, 38, 45,
7, 36, 79, 16, 37, 68,
48, 7, 9, 18, 70, 26, 6,
18, 72, 79, 46, 59, 79, 29, 90,
20, 76, 87, 11, 32, 7, 7, 49, 18,
27, 83, 58, 35, 71, 11, 25, 57... | Give a code snippet in #C
Starting from the top of a pyramid of numbers like this, you can walk down going one step on the right or on the left, until you reach the bottom row:
55
94 48
95 30 96
77 71 26 67
One of such walk... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Problem_of_Apollonius | Problem of Apollonius |
Task
Implement a solution to the Problem of Apollonius (description on Wikipedia) which is the problem of finding the circle that is tangent to three specified circles (colored black in the diagram below to the right).
There is an algebraic solution which is pretty straightforward.
The solutions to the ... | #PL.2FI | PL/I | Apollonius: procedure options (main); /* 29 October 2013 */
define structure
1 circle,
2 x float (15),
2 y float (15),
2 radius float (15);
declare (c1 , c2, c3, result) type (circle);
c1.x = 0; c1.y = 0; c1.radius = 1;
c2.x = 4; c2.y = 0; c2.radius = 1;
c3.x = 2; c3.y = 4; c3... | Give a code snippet in #PL.2FI
Task
Implement a solution to the Problem of Apollonius (description on Wikipedia) which is the problem of finding the circle that is tangent to three specified circles (colored black in the diagram below to the right).
There is an algebraic solution which is pretty straightf... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Colour_pinstripe/Display | Colour pinstripe/Display | The task is to create 1 pixel wide coloured vertical pinstripes with a sufficient number of pinstripes to span the entire width of the graphics display.
The pinstripes should either follow the system palette sequence, or a sequence that includes:
black, red, green, blue, magenta, cyan, yellow, and ... | #Befunge | Befunge | "%":*3-"`"8*>4/::8%00p8/10p4*\55+"3P",,,:.\.5v
5+:,1vv\%2:%8/-g025:\-1_$$55+,\:v1+*8g01g00_@>
024,.<>2/:2%\2/...1+\:>^<:\0:\-1_$20g1-:20p^1p | Give a code snippet in #Befunge
The task is to create 1 pixel wide coloured vertical pinstripes with a sufficient number of pinstripes to span the entire width of the graphics display.
The pinstripes should either follow the system palette sequence, or a sequence that includes:
black, red, green, blue, m... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Pascal%27s_triangle | Pascal's triangle | Pascal's triangle is an arithmetic and geometric figure often associated with the name of Blaise Pascal, but also studied centuries earlier in India, Persia, China and elsewhere.
Its first few rows look like this:
1
1 1
1 2 1
1 3 3 1
where each element of each row is either 1 or the sum of the two elemen... | #IS-BASIC | IS-BASIC | 100 PROGRAM "PascalTr.bas"
110 TEXT 80
120 LET ROW=12
130 FOR I=0 TO ROW
140 LET C=1
150 PRINT TAB(37-I*3);
160 FOR K=0 TO I
170 PRINT USING " #### ":C;
180 LET C=C*(I-K)/(K+1)
190 NEXT
200 PRINT
210 NEXT | Give a code snippet in #IS-BASIC
Pascal's triangle is an arithmetic and geometric figure often associated with the name of Blaise Pascal, but also studied centuries earlier in India, Persia, China and elsewhere.
Its first few rows look like this:
1
1 1
1 2 1
1 3 3 1
where each element of each row is eit... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Babbage_problem | Babbage problem |
Charles Babbage, looking ahead to the sorts of problems his Analytical Engine would be able to solve, gave this example:
What is the smallest positive integer whose square ends in the digits 269,696?
— Babbage, letter to Lord Bowden, 1837; see Hollingdale and Tootill, Electronic Computers, second edition, 1970, p.... | #D | D | // It's basically the same as any other version.
// What can be observed is that 269696 is even, so we have to consider only even numbers,
// because only the square of even numbers is even.
import std.math;
import std.stdio;
void main( )
{
// get smallest number <= sqrt(269696)
int k = cast(int)(sqrt(26969... | Give a code snippet in #D
Charles Babbage, looking ahead to the sorts of problems his Analytical Engine would be able to solve, gave this example:
What is the smallest positive integer whose square ends in the digits 269,696?
— Babbage, letter to Lord Bowden, 1837; see Hollingdale and Tootill, Electronic Computer... | 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... | #Wren | Wren | var alpha = []
for (c in 97..122) alpha.add(String.fromByte(c))
System.print(alpha.join()) | Give a code snippet in #Wren
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 r... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Move-to-front_algorithm | Move-to-front algorithm | Given a symbol table of a zero-indexed array of all possible input symbols
this algorithm reversibly transforms a sequence
of input symbols into an array of output numbers (indices).
The transform in many cases acts to give frequently repeated input symbols
lower indices which is useful in some compression algorithms... | #ALGOL_68 | ALGOL 68 | # move the character at text pos to the front of text #
# note text pos is based from 0 #
PROC move to front = ( STRING text, INT text pos )STRING:
IF text pos < 1
THEN
# the character is already at the front (or not in the string) ... | Give a code snippet in #ALGOL_68
Given a symbol table of a zero-indexed array of all possible input symbols
this algorithm reversibly transforms a sequence
of input symbols into an array of output numbers (indices).
The transform in many cases acts to give frequently repeated input symbols
lower indices which is use... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Reflection/List_methods | Reflection/List methods | Task
The goal is to get the methods of an object, as names, values or both.
Some languages offer dynamic methods, which in general can only be inspected if a class' public API includes a way of listing them.
| #Phix | Phix | enum METHODS, PROPERTIES
sequence all_methods = {}
function method_visitor(object key, object /*data*/, /*user_data*/)
all_methods = append(all_methods,key)
return 1
end function
function get_all_methods(object o)
all_methods = {}
traverse_dict(method_visitor,0,o[METHODS])
return all_methods
end ... | Give a code snippet in #Phix
Task
The goal is to get the methods of an object, as names, values or both.
Some languages offer dynamic methods, which in general can only be inspected if a class' public API includes a way of listing them.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Shoelace_formula_for_polygonal_area | Shoelace formula for polygonal area | Given the n + 1 vertices x[0], y[0] .. x[N], y[N] of a simple polygon described in a clockwise direction, then the polygon's area can be calculated by:
abs( (sum(x[0]*y[1] + ... x[n-1]*y[n]) + x[N]*y[0]) -
(sum(x[1]*y[0] + ... x[n]*y[n-1]) + x[0]*y[N])
) / 2
(Where abs returns the absolute value)
Task
Write ... | #Kotlin | Kotlin | // version 1.1.3
class Point(val x: Int, val y: Int) {
override fun toString() = "($x, $y)"
}
fun shoelaceArea(v: List<Point>): Double {
val n = v.size
var a = 0.0
for (i in 0 until n - 1) {
a += v[i].x * v[i + 1].y - v[i + 1].x * v[i].y
}
return Math.abs(a + v[n - 1].x * v[0].y - v... | Give a code snippet in #Kotlin
Given the n + 1 vertices x[0], y[0] .. x[N], y[N] of a simple polygon described in a clockwise direction, then the polygon's area can be calculated by:
abs( (sum(x[0]*y[1] + ... x[n-1]*y[n]) + x[N]*y[0]) -
(sum(x[1]*y[0] + ... x[n]*y[n-1]) + x[0]*y[N])
) / 2
(Where abs returns t... | christopher/rosetta-code | |
http://rosettacode.org/wiki/CSV_to_HTML_translation | CSV to HTML translation | Consider a simplified CSV format where all rows are separated by a newline
and all columns are separated by commas.
No commas are allowed as field data, but the data may contain
other characters and character sequences that would
normally be escaped when converted to HTML
Task
Create a function that takes a st... | #PHP | PHP |
<?php
$csv = <<<EOT
Character,Speech
The multitude,The messiah! Show us the messiah!
Brians mother,<angry>Now you listen here! He's not the messiah; he's a very naughty boy! Now go away!</angry>
The multitude,Who are you?
Brians mother,I'm his mother; that's who!
The multitude,Behold his mother! Behold his mother!
EO... | Give a code snippet in #PHP
Consider a simplified CSV format where all rows are separated by a newline
and all columns are separated by commas.
No commas are allowed as field data, but the data may contain
other characters and character sequences that would
normally be escaped when converted to HTML
Task
Crea... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Mutual_recursion | Mutual recursion | Two functions are said to be mutually recursive if the first calls the second,
and in turn the second calls the first.
Write two mutually recursive functions that compute members of the Hofstadter Female and Male sequences defined as:
F
(
0
)
=
1
;
M
(
0
)
=
0
F
(
n
)
=
n
−
M
(
F
(
n
−
1
)
)
,
... | #Arturo | Arturo | f: $[n][ if? n=0 -> 1 else -> n-m f n-1 ]
m: $[n][ if? n=0 -> 0 else -> n-f m n-1 ]
loop 0..20 'i [
print ["f(" i ")=" f i]
print ["m(" i ")=" m i]
print ""
] | Give a code snippet in #Arturo
Two functions are said to be mutually recursive if the first calls the second,
and in turn the second calls the first.
Write two mutually recursive functions that compute members of the Hofstadter Female and Male sequences defined as:
F
(
0
)
=
1
;
M
(
0
)
=
0
F
(
n... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Catalan_numbers | Catalan numbers | Catalan numbers
You are encouraged to solve this task according to the task description, using any language you may know.
Catalan numbers are a sequence of numbers which can be defined directly:
C
n
=
1
n
+
1
(
2
n
n
)
=
(
2
n
)
!
(
n
+
1
)
!
n
!
for
n
≥
0.
{\displaystyle C... | #Modula-2 | Modula-2 | MODULE CatalanNumbers;
FROM FormatString IMPORT FormatString;
FROM Terminal IMPORT WriteString,WriteLn,ReadChar;
PROCEDURE binomial(m,n : LONGCARD) : LONGCARD;
VAR r,d : LONGCARD;
BEGIN
r := 1;
d := m - n;
IF d>n THEN
n := d;
d := m - n;
END;
WHILE m>n DO
r := r * m;
... | Give a code snippet in #Modula-2
Catalan numbers
You are encouraged to solve this task according to the task description, using any language you may know.
Catalan numbers are a sequence of numbers which can be defined directly:
C
n
=
1
n
+
1
(
2
n
n
)
=
(
2
n
)
!
(
n
+
1
)
!
n
!
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Keyboard_input/Obtain_a_Y_or_N_response | Keyboard input/Obtain a Y or N response |
Task
Obtain a valid Y or N response from the keyboard.
The keyboard should be flushed, so that any outstanding key-presses are removed, preventing any existing Y or N key-press from being evaluated.
The response should be obtained as soon as Y or N are pressed, and there should be no need t... | #Liberty_BASIC | Liberty BASIC |
nomainwin
open "Y/N" for graphics_nsb_nf as #1
#1 "trapclose Quit"
#1 "down;setfocus;when characterInput KeyCheck"
#1 "place 10 50;\Press Y or N"
Inkey$=""
wait
sub KeyCheck hndle$,k$
k$=upper$(k$)
#hndle$ "cls;place 10 50"
select case k$
case "Y"
#hndle$ "\ Yes"
case "N"
... | Give a code snippet in #Liberty_BASIC
Task
Obtain a valid Y or N response from the keyboard.
The keyboard should be flushed, so that any outstanding key-presses are removed, preventing any existing Y or N key-press from being evaluated.
The response should be obtained as soon as Y or N are... | 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
| #Vala | Vala | valac maps.vala --pkg gee-1.0
| Give a code snippet in #Vala
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/Levenshtein_distance | Levenshtein distance |
This page uses content from Wikipedia. The original article was at Levenshtein distance. 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 information theory and computer science, the Levenshtein ... | #Haskell | Haskell | levenshtein :: Eq a => [a] -> [a] -> Int
levenshtein s1 s2 = last $ foldl transform [0 .. length s1] s2
where
transform ns@(n:ns1) c = scanl calc (n + 1) $ zip3 s1 ns ns1
where
calc z (c1, x, y) = minimum [y + 1, z + 1, x + fromEnum (c1 /= c)]
main :: IO ()
main = print (levenshtein "kitten" "sitt... | Give a code snippet in #Haskell
This page uses content from Wikipedia. The original article was at Levenshtein distance. 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 information theory and c... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Four_is_magic | Four is magic | Task
Write a subroutine, function, whatever it may be called in your language, that takes an integer number and returns an English text sequence starting with the English cardinal representation of that integer, the word 'is' and then the English cardinal representation of the count of characters that made up the firs... | #JavaScript | JavaScript | Object.getOwnPropertyNames(this).includes('BigInt') | Give a code snippet in #JavaScript
Task
Write a subroutine, function, whatever it may be called in your language, that takes an integer number and returns an English text sequence starting with the English cardinal representation of that integer, the word 'is' and then the English cardinal representation of the count... | 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... | #CLU | CLU | % Recaman sequence
recaman = cluster is new, fetch
rep = array[int]
new = proc () returns (cvt)
a: rep := rep$predict(0,1000000)
rep$addh(a,0)
return(a)
end new
% Find the N'th element of the Recaman sequence
fetch = proc (a: cvt, n: int) returns (int)
if n > rep$... | Give a code snippet in #CLU
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... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Break_OO_privacy | Break OO privacy | Show how to access private or protected members of a class in an object-oriented language from outside an instance of the class, without calling non-private or non-protected members of the class as a proxy.
The intent is to show how a debugger, serializer, or other meta-programming tool might access information that is... | #Logtalk | Logtalk | :- object(foo).
% be sure that context switching calls are allowed
:- set_logtalk_flag(context_switching_calls, allow).
% declare and define a private method
:- private(bar/1).
bar(1).
bar(2).
bar(3).
:- end_object. | Give a code snippet in #Logtalk
Show how to access private or protected members of a class in an object-oriented language from outside an instance of the class, without calling non-private or non-protected members of the class as a proxy.
The intent is to show how a debugger, serializer, or other meta-programming tool... | christopher/rosetta-code | |
http://rosettacode.org/wiki/I_before_E_except_after_C | I before E except after C | The phrase "I before E, except after C" is a
widely known mnemonic which is supposed to help when spelling English words.
Task
Using the word list from http://wiki.puzzlers.org/pub/wordlists/unixdict.txt,
check if the two sub-clauses of the phrase are plausible individually:
"I before E when not pre... | #D | D | import std.file;
import std.stdio;
int main(string[] args) {
if (args.length < 2) {
stderr.writeln(args[0], " filename");
return 1;
}
int cei, cie, ie, ei;
auto file = File(args[1]);
foreach(line; file.byLine) {
auto res = eval(cast(string) line);
cei += res.cei;
... | Give a code snippet in #D
The phrase "I before E, except after C" is a
widely known mnemonic which is supposed to help when spelling English words.
Task
Using the word list from http://wiki.puzzlers.org/pub/wordlists/unixdict.txt,
check if the two sub-clauses of the phrase are plausible individually:
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterat... | #Bracmat | Bracmat | (
=
. !arg:0&1
| !arg
* ( (
= r
. !arg:?r
&
' (
. !arg:0&1
| !arg*(($r)$($r))$(!arg+-1)
)
... | Give a code snippet in #Bracmat
Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Remove_lines_from_a_file | Remove lines from a file | Task
Remove a specific line or a number of lines from a file.
This should be implemented as a routine that takes three parameters (filename, starting line, and the number of lines to be removed).
For the purpose of this task, line numbers and the number of lines start at one, so to remove the first two lines from th... | #Snobol4 | Snobol4 | * Remove lines from a file
* Function to remove a chunk of lines from a file, will go backward, too, if numlines < 0
define("remlines(filename,startline,numlines)row,rowcount,lastline,swap")
:(remlines_end)
remlines
input(.inp1,1,filename) :f(freturn)
output(.tmp1,2,"/tmp/Removem") :f(freturn)
rowcount = ... | Give a code snippet in #Snobol4
Task
Remove a specific line or a number of lines from a file.
This should be implemented as a routine that takes three parameters (filename, starting line, and the number of lines to be removed).
For the purpose of this task, line numbers and the number of lines start at one, so to r... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Cantor_set | Cantor set | Task
Draw a Cantor set.
See details at this Wikipedia webpage: Cantor set
| #Perl | Perl | use strict;
use feature 'say';
sub cantor {
our($height) = @_;
my $width = 3 ** ($height - 1);
our @lines = ('#' x $width) x $height;
sub trim_middle_third {
my($len, $start, $index) = @_;
my $seg = int $len / 3
or return;
for my $i ( $index .. $height - 1 ) {... | Give a code snippet in #Perl
Task
Draw a Cantor set.
See details at this Wikipedia webpage: Cantor set
| 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... | #Rust | Rust | use std::{
convert::TryFrom,
fmt::{Debug, Display, Formatter},
io::Read,
};
pub struct ReadUtf8<I: Iterator> {
source: std::iter::Peekable<I>,
}
impl<R: Read> From<R> for ReadUtf8<std::io::Bytes<R>> {
fn from(source: R) -> Self {
ReadUtf8 {
source: source.bytes().peekable(),
... | Give a code snippet in #Rust
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 suppor... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Arithmetic/Integer | Arithmetic/Integer |
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 |... | #dc | dc | [Enter 2 integers on 1 line.
Use whitespace to separate. Example: 2 3
Use underscore for negative integers. Example: _10
]P ? sb sa
[add: ]P la lb + p sz
[sub: ]P la lb - p sz
[mul: ]P la lb * p sz
[div: ]P la lb / p sz [truncates toward zero]sz
[mod: ]P la lb % p sz [sign matches first operand]sz
[pow: ]P la lb ... | Give a code snippet in #dc
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
Con... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sorting_algorithms/Bubble_sort | Sorting algorithms/Bubble sort |
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
... | #Dart | Dart | List<num> bubbleSort(List<num> list) {
var retList = new List<num>.from(list);
var tmp;
var swapped = false;
do {
swapped = false;
for(var i = 1; i < retList.length; i++) {
if(retList[i - 1] > retList[i]) {
tmp = retList[i - 1];
retList[i - 1] = retList[i];
retList[i] = tmp... | Give a code snippet in #Dart
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/Sort_using_a_custom_comparator | Sort using a custom comparator |
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
... | #Common_Lisp | Common Lisp | CL-USER> (defvar *strings*
(list "Cat" "apple" "Adam" "zero" "Xmas" "quit" "Level" "add" "Actor" "base" "butter"))
*STRINGS*
CL-USER> (sort *strings* #'string-lessp)
("Actor" "Adam" "add" "apple" "base" "butter" "Cat" "Level" "quit" "Xmas"
"zero") | Give a code snippet in #Common_Lisp
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 |
Qu... | christopher/rosetta-code | |
http://rosettacode.org/wiki/User_input/Graphical | User input/Graphical |
In this task, the goal is to input a string and the integer 75000, from graphical user interface.
See also: User input/Text
| #Nanoquery | Nanoquery | import Nanoquery.Util.Windows
// a function to handle the main window closing
def finish(caller, event)
exit
end
// create a window
w = new(Window, "Input").setTitle("Input")
w.setSize(320, 190)
w.setHandler(w.closing, finish)
// create two labels to go next to the input boxes
stringlabel = new(Label).setParent(... | Give a code snippet in #Nanoquery
In this task, the goal is to input a string and the integer 75000, from graphical user interface.
See also: User input/Text
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Non-decimal_radices/Convert | Non-decimal radices/Convert | Number base conversion is when you express a stored integer in an integer base, such as in octal (base 8) or binary (base 2). It also is involved when you take a string representing a number in a given base and convert it to the stored integer form. Normally, a stored integer is in binary, but that's typically invisibl... | #M4 | M4 | eval(26,16)
define(`frombase',`eval(0r$2:$1)')
frombase(1a,16) | Give a code snippet in #M4
Number base conversion is when you express a stored integer in an integer base, such as in octal (base 8) or binary (base 2). It also is involved when you take a string representing a number in a given base and convert it to the stored integer form. Normally, a stored integer is in binary, b... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Power_set | Power set | A set is a collection (container) of certain values,
without any particular order, and no repeated values.
It corresponds with a finite set in mathematics.
A set can be implemented as an associative array (partial mapping)
in which the value of each key-value pair is ignored.
Given a set S, the power set (or pow... | #K | K |
ps:{x@&:'+2_vs!_2^#x}
| Give a code snippet in #K
A set is a collection (container) of certain values,
without any particular order, and no repeated values.
It corresponds with a finite set in mathematics.
A set can be implemented as an associative array (partial mapping)
in which the value of each key-value pair is ignored.
Given a s... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Strip_comments_from_a_string | Strip comments from a string | Strip comments from a string
You are encouraged to solve this task according to the task description, using any language you may know.
The task is to remove text that follow any of a set of comment markers, (in these examples either a hash or a semicolon) from a string or input line.
Whitespace debacle: There is s... | #F.23 | F# | let stripComments s =
s
|> Seq.takeWhile (fun c -> c <> '#' && c <> ';')
|> Seq.map System.Char.ToString
|> Seq.fold (+) "" | Give a code snippet in #F.23
Strip comments from a string
You are encouraged to solve this task according to the task description, using any language you may know.
The task is to remove text that follow any of a set of comment markers, (in these examples either a hash or a semicolon) from a string or input line.
Wh... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Random_number_generator_(included) | Random number generator (included) | The task is to:
State the type of random number generator algorithm used in a language's built-in random number generator. If the language or its immediate libraries don't provide a random number generator, skip this task.
If possible, give a link to a wider explanation of the algorithm used.
Note: the task is not t... | #Io | Io | setrand(3)
random(6)+1
\\ chosen by fair dice roll.
\\ guaranteed to the random. | Give a code snippet in #Io
The task is to:
State the type of random number generator algorithm used in a language's built-in random number generator. If the language or its immediate libraries don't provide a random number generator, skip this task.
If possible, give a link to a wider explanation of the algorithm u... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Copy_a_string | Copy a string | This task is about copying a string.
Task
Where it is relevant, distinguish between copying the contents of a string
versus making an additional reference to an existing string.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
W... | #Amazing_Hopper | Amazing Hopper |
#include <hopper.h>
main:
s = "string to copy"
t = s
{s,"\n",t}println
exit(0)
| Give a code snippet in #Amazing_Hopper
This task is about copying a string.
Task
Where it is relevant, distinguish between copying the contents of a string
versus making an additional reference to an existing string.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Identity_matrix | Identity matrix | Task
Build an identity matrix of a size known at run-time.
An identity matrix is a square matrix of size n × n,
where the diagonal elements are all 1s (ones),
and all the other elements are all 0s (zeroes).
I
n
=
[
1
0
0
⋯
0
0
1
0
⋯
0
0
0
1
⋯
0
⋮
⋮
⋮
⋱
... | #AWK | AWK |
# syntax: GAWK -f IDENTITY_MATRIX.AWK size
BEGIN {
size = ARGV[1]
if (size !~ /^[0-9]+$/) {
print("size invalid or missing from command line")
exit(1)
}
for (i=1; i<=size; i++) {
for (j=1; j<=size; j++) {
x = (i == j) ? 1 : 0
printf("%2d",x) # print
arr[i,j] =... | Give a code snippet in #AWK
Task
Build an identity matrix of a size known at run-time.
An identity matrix is a square matrix of size n × n,
where the diagonal elements are all 1s (ones),
and all the other elements are all 0s (zeroes).
I
n
=
[
1
0
0
⋯
0
0
1
0
⋯
0
0
0
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Fibonacci_sequence | Fibonacci sequence | The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are generally considered too slow ... | #Chef | Chef | Stir-Fried Fibonacci Sequence.
An unobfuscated iterative implementation.
It prints the first N + 1 Fibonacci numbers,
where N is taken from standard input.
Ingredients.
0 g last
1 g this
0 g new
0 g input
Method.
Take input from refrigerator.
Put this into 4th mixing bowl.
Loop the input.
Clean the 3rd mixing bow... | Give a code snippet in #Chef
The Fibonacci sequence is a sequence Fn of natural numbers defined recursively:
F0 = 0
F1 = 1
Fn = Fn-1 + Fn-2, if n>1
Task
Write a function to generate the nth Fibonacci number.
Solutions can be iterative or recursive (though recursive solutions are ... | christopher/rosetta-code | |
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... | #Raku | Raku | mkdir 'path/to/dir' | Give a code snippet in #Raku
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/String_prepend | String prepend |
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 |... | #Dyalect | Dyalect | var s = "world!"
s = "Hello " + s
print(s) | Give a code snippet in #Dyalect
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/Pinstripe/Display | Pinstripe/Display | Sample image
The task is to demonstrate the creation of a series of vertical pinstripes across the entire width of the display.
in the first quarter the pinstripes should alternate one pixel white, one pixel black = 1 pixel wide vertical pinestripes
Quarter of the way down the display, we can switch to a wider 2 pi... | #Gambas | Gambas | 'WARNING this takes a time to display
'Use the 'gb.qt4' component
Public Sub Form_Open()
Dim iColour As Integer[] = [Color.Black, Color.white]
Dim hPanel As Panel
Dim siCount, siCounter, siSet As Short
With Me
.Arrangement = Arrange.Row
.Border = False
.Height = Desktop.Height
.Width = Desktop.Width
.Full... | Give a code snippet in #Gambas
Sample image
The task is to demonstrate the creation of a series of vertical pinstripes across the entire width of the display.
in the first quarter the pinstripes should alternate one pixel white, one pixel black = 1 pixel wide vertical pinestripes
Quarter of the way down the displa... | 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... | #Visual_Basic | Visual Basic | TYPE syswindowstru
screenheight AS INTEGER
screenwidth AS INTEGER
maxheight AS INTEGER
maxwidth AS INTEGER
END TYPE
DIM syswindow AS syswindowstru
' Determine the height and width of the screen
syswindow.screenwidth = Screen.Width / Screen.TwipsPerPixelX
syswindow.screenheight=Screen.Height / Screen.TwipsP... | Give a code snippet in #Visual_Basic
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... | christopher/rosetta-code | |
http://rosettacode.org/wiki/One_of_n_lines_in_a_file | One of n lines in a file | A method of choosing a line randomly from a file:
Without reading the file more than once
When substantial parts of the file cannot be held in memory
Without knowing how many lines are in the file
Is to:
keep the first line of the file as a possible choice, then
Read the second line of the file if possible and m... | #Common_Lisp | Common Lisp | (defun one-of-n-fn ()
(let ((cur 0) (sel nil))
#'(lambda (v)
(setq cur (+ cur 1))
(if (eql 0 (random cur)) (setq sel v))
sel)))
(defun test-one-of-n ()
(let ((counts (make-array 10 :initial-contents '(0 0 0 0 0 0 0 0 0 0)))
(fnt))
(do ((test 0 (+ 1 test)))
((eql tes... | Give a code snippet in #Common_Lisp
A method of choosing a line randomly from a file:
Without reading the file more than once
When substantial parts of the file cannot be held in memory
Without knowing how many lines are in the file
Is to:
keep the first line of the file as a possible choice, then
Read the seco... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Knight%27s_tour | Knight's tour |
Task
Problem: you have a standard 8x8 chessboard, empty but for a single knight on some square. Your task is to emit a series of legal knight moves that result in the knight visiting every square on the chessboard exactly once. Note that it is not a requirement that the tour be "closed"; that is, the knight need not e... | #C.23 | C# | using System;
using System.Collections.Generic;
namespace prog
{
class MainClass
{
const int N = 8;
readonly static int[,] moves = { {+1,-2},{+2,-1},{+2,+1},{+1,+2},
{-1,+2},{-2,+1},{-2,-1},{-1,-2} };
struct ListMoves
{
public int x, y;
public ListMoves( int _x, int _... | Give a code snippet in #C.23
Task
Problem: you have a standard 8x8 chessboard, empty but for a single knight on some square. Your task is to emit a series of legal knight moves that result in the knight visiting every square on the chessboard exactly once. Note that it is not a requirement that the tour be "closed"; ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/ABC_problem | ABC problem | ABC problem
You are encouraged to solve this task according to the task description, using any language you may know.
You are given a collection of ABC blocks (maybe like the ones you had when you were a kid).
There are twenty blocks with two letters on each block.
A complete alphabet is guaranteed amongst all sid... | #Pascal | Pascal |
#!/usr/bin/instantfpc
//program ABCProblem;
{$mode objfpc}{$H+}
uses SysUtils, Classes;
const
// every couple of chars is a block
// remove one by replacing its 2 chars by 2 spaces
Blocks = 'BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM';
BlockSize = 3;
function can_make_word(Str: Strin... | Give a code snippet in #Pascal
ABC problem
You are encouraged to solve this task according to the task description, using any language you may know.
You are given a collection of ABC blocks (maybe like the ones you had when you were a kid).
There are twenty blocks with two letters on each block.
A complete alphab... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Arithmetic-geometric_mean | Arithmetic-geometric mean |
This page uses content from Wikipedia. The original article was at Arithmetic-geometric mean. 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)
Task
Write a function to compute the arithmetic-geomet... | #Potion | Potion | sqrt = (x) :
xi = 1
7 times :
xi = (xi + x / xi) / 2
.
xi
.
agm = (x, y) :
7 times :
a = (x + y) / 2
g = sqrt(x * y)
x = a
y = g
.
x
. | Give a code snippet in #Potion
This page uses content from Wikipedia. The original article was at Arithmetic-geometric mean. 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)
Task
Write a function ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Discordian_date | Discordian date |
Task
Convert a given date from the Gregorian calendar to the Discordian calendar.
| #Go | Go | package ddate
import (
"strconv"
"strings"
"time"
)
// Predefined formats for DiscDate.Format
const (
DefaultFmt = "Pungenday, Discord 5, 3131 YOLD"
OldFmt = `Today is Pungenday, the 5th day of Discord in the YOLD 3131
Celebrate Mojoday`
)
// Formats passed to DiscDate.Format are proty... | Give a code snippet in #Go
Task
Convert a given date from the Gregorian calendar to the Discordian calendar.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Secure_temporary_file | Secure temporary file | Task
Create a temporary file, securely and exclusively (opening it such that there are no possible race conditions).
It's fine assuming local filesystem semantics (NFS or other networking filesystems can have signficantly more complicated semantics for satisfying the "no race conditions" criteria).
The function shou... | #Ruby | Ruby | irb(main):001:0> require 'tempfile'
=> true
irb(main):002:0> f = Tempfile.new('foo')
=> #<File:/tmp/foo20081226-307-10p746n-0>
irb(main):003:0> f.path
=> "/tmp/foo20081226-307-10p746n-0"
irb(main):004:0> f.close
=> nil
irb(main):005:0> f.unlink
=> #<Tempfile: (closed)> | Give a code snippet in #Ruby
Task
Create a temporary file, securely and exclusively (opening it such that there are no possible race conditions).
It's fine assuming local filesystem semantics (NFS or other networking filesystems can have signficantly more complicated semantics for satisfying the "no race conditions"... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Terminal_control/Cursor_positioning | Terminal control/Cursor positioning |
Task
Move the cursor to column 3, row 6, and display the word "Hello" (without the quotes), so that the letter H is in column 3 on row 6.
| #Quackery | Quackery | [ number$ swap number$
$ 'print("\033[' rot join
char ; join
swap join
$ 'H", end="")' join
python ] is cursor-at ( x y --> )
3 6 cursor-at say "Hello" | Give a code snippet in #Quackery
Task
Move the cursor to column 3, row 6, and display the word "Hello" (without the quotes), so that the letter H is in column 3 on row 6.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Function_prototype | Function prototype | Some languages provide the facility to declare functions and subroutines through the use of function prototyping.
Task
Demonstrate the methods available for declaring prototypes within the language. The provided solutions should include:
An explanation of any placement restrictions for prototype declarations
A p... | #Ol | Ol |
'DECLARE FUNCTION' ABBREVIATED TO '!'
! f() ' a procedure with no params
! f(int a) ' with 1 int param
! f(int *a) ' with 1 int pointer param
! f(int a, int b, inc c) ' with 3 int params
! f(int a,b,c) ' compaction with 3 int params
! f(string s, in... | Give a code snippet in #Ol
Some languages provide the facility to declare functions and subroutines through the use of function prototyping.
Task
Demonstrate the methods available for declaring prototypes within the language. The provided solutions should include:
An explanation of any placement restrictions for... | 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... | #PL.2FI | PL/I |
/* Declaration for an image, suitable for BMP files. */
declare image(0:500, 0:500) bit (24) aligned;
image = '000000000000000011111111'b;
/* Sets the entire image to red. */
image(10,40) = '111111110000000000000000'b;
/* Sets one pixel to blue. */
declare color bit (24) aligned;
color = image(20,50); /* ... | Give a code snippet in #PL.2FI
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 c... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Terminal_control/Clear_the_screen | Terminal control/Clear the screen | Task
Clear the terminal window.
| #Visual_Basic_.NET | Visual Basic .NET | System.Console.Clear() | Give a code snippet in #Visual_Basic_.NET
Task
Clear the terminal window.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Exponentiation_operator | Exponentiation operator | Most programming languages have a built-in implementation of exponentiation.
Task
Re-implement integer exponentiation for both intint and floatint as both a procedure, and an operator (if your language supports operator definition).
If the language supports operator (or procedure) overloading, then an ov... | #FreeBASIC | FreeBASIC | ' FB 1.05.0
' Note that 'base' is a keyword in FB, so we use 'base_' instead as a parameter
Function Pow Overload (base_ As Double, exponent As Integer) As Double
If exponent = 0.0 Then Return 1.0
If exponent = 1.0 Then Return base_
If exponent < 0.0 Then Return 1.0 / Pow(base_, -exponent)
Dim power As Doub... | Give a code snippet in #FreeBASIC
Most programming languages have a built-in implementation of exponentiation.
Task
Re-implement integer exponentiation for both intint and floatint as both a procedure, and an operator (if your language supports operator definition).
If the language supports operator (or... | 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... | #Maple | Maple | Point:= Record(x = 2,y = 4):
Point:-x;
Point:-y; | Give a code snippet in #Maple
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.
R... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Literals/String | Literals/String | Task
Show literal specification of characters and strings.
If supported, show how the following work:
verbatim strings (quotes where escape sequences are quoted literally)
here-strings
Also, discuss which quotes expand variables.
Related tasks
Special characters
Here document
Other tasks r... | #Java | Java | char a = 'a'; // prints as: a
String b = "abc"; // prints as: abc
char doubleQuote = '"'; // prints as: "
char singleQuote = '\''; // prints as: '
String singleQuotes = "''"; // prints as: ''
String doubleQuotes = "\"\""; // prints as: "" | Give a code snippet in #Java
Task
Show literal specification of characters and strings.
If supported, show how the following work:
verbatim strings (quotes where escape sequences are quoted literally)
here-strings
Also, discuss which quotes expand variables.
Related tasks
Special characters
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Catalan_numbers | Catalan numbers | Catalan numbers
You are encouraged to solve this task according to the task description, using any language you may know.
Catalan numbers are a sequence of numbers which can be defined directly:
C
n
=
1
n
+
1
(
2
n
n
)
=
(
2
n
)
!
(
n
+
1
)
!
n
!
for
n
≥
0.
{\displaystyle C... | #ooRexx | ooRexx | loop i = 0 to 15
say "catI("i") =" .catalan~catI(i)
say "catR1("i") =" .catalan~catR1(i)
say "catR2("i") =" .catalan~catR2(i)
end
-- This is implemented as static members on a class object
-- so that the code is able to keep state information between calls. This
-- memoization will speed up things like f... | Give a code snippet in #ooRexx
Catalan numbers
You are encouraged to solve this task according to the task description, using any language you may know.
Catalan numbers are a sequence of numbers which can be defined directly:
C
n
=
1
n
+
1
(
2
n
n
)
=
(
2
n
)
!
(
n
+
1
)
!
n
!
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Search_a_list | Search a list | Task[edit]
Find the index of a string (needle) in an indexable, ordered collection of strings (haystack).
Raise an exception if the needle is missing.
If there is more than one occurrence then return the smallest index to the needle.
Extra credit
Return the largest index to a needle that has multiple occurrences in ... | #REXX | REXX | /*REXX program searches a collection of strings (an array of periodic table elements).*/
hay.= /*initialize the haystack collection. */
hay.1 = 'sodium'
hay.2 = 'phosphorous'
hay.3 = 'californium'
hay.4 = 'copernicium'
hay.5 = 'gold'
hay.6 = 'thallium'
hay.7 = 'carbo... | Give a code snippet in #REXX
Task[edit]
Find the index of a string (needle) in an indexable, ordered collection of strings (haystack).
Raise an exception if the needle is missing.
If there is more than one occurrence then return the smallest index to the needle.
Extra credit
Return the largest index to a needle tha... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Non-decimal_radices/Convert | Non-decimal radices/Convert | Number base conversion is when you express a stored integer in an integer base, such as in octal (base 8) or binary (base 2). It also is involved when you take a string representing a number in a given base and convert it to the stored integer form. Normally, a stored integer is in binary, but that's typically invisibl... | #J | J | 2b100 8b100 10b_100 16b100 36b100 36bzy
4 64 _100 256 1296 1294 | Give a code snippet in #J
Number base conversion is when you express a stored integer in an integer base, such as in octal (base 8) or binary (base 2). It also is involved when you take a string representing a number in a given base and convert it to the stored integer form. Normally, a stored integer is in binary, bu... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Multiplication_tables | Multiplication tables | Task
Produce a formatted 12×12 multiplication table of the kind memorized by rote when in primary (or elementary) school.
Only print the top half triangle of products.
| #FreeBASIC | FreeBASIC |
' FB 1.05.0 Win64
Print " X|";
For i As Integer = 1 To 12
Print Using "####"; i;
Next
Print
Print "---+"; String(48, "-")
For i As Integer = 1 To 12
Print Using "###"; i;
Print"|"; Spc(4 * (i - 1));
For j As Integer = i To 12
Print Using "####"; i * j;
Next j
Print
Next i
Print
Print "Pr... | Give a code snippet in #FreeBASIC
Task
Produce a formatted 12×12 multiplication table of the kind memorized by rote when in primary (or elementary) school.
Only print the top half triangle of products.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Parametric_polymorphism | Parametric polymorphism | Parametric Polymorphism
type variables
Task
Write a small example for a type declaration that is parametric over another type, together with a short bit of code (and its type signature) that uses it.
A good example is a container type, let's say a binary tree, together with some function that traverses the tree, ... | #C3 | C3 | module tree<Type>;
struct Tree
{
Type value;
Tree* left;
Tree* right;
}
fn void Tree.replaceAll(Tree* a_tree, Type new_value)
{
a_tree.value = new_value;
if (a_tree.left) a_tree.left.replaceAll(new_value);
if (a_tree.right) a_tree.right.replaceAll(new_value);
}
| Give a code snippet in #C3
Parametric Polymorphism
type variables
Task
Write a small example for a type declaration that is parametric over another type, together with a short bit of code (and its type signature) that uses it.
A good example is a container type, let's say a binary tree, together with some functi... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #CoffeeScript | CoffeeScript | # one line comment
### multi
line
comment ### | Give a code snippet in #CoffeeScript
Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Convert_seconds_to_compound_duration | Convert seconds to compound duration | Task
Write a function or program which:
takes a positive integer representing a duration in seconds as input (e.g., 100), and
returns a string which shows the same duration decomposed into:
weeks,
days,
hours,
minutes, and
seconds.
This is detailed below (e.g., "2 hr, 59 sec").
Demonstrat... | #ALGOL_68 | ALGOL 68 | # MODE to hold the compound duration #
MODE DURATION = STRUCT( INT weeks, days, hours, minutes, seconds );
# returns seconds converted to a DURATION #
OP TODURATION = ( LONG INT seconds )DURATION:
BEGIN
LONG INT time := seconds;
DURATION result := DURATION( 0, 0, 0, 0, 0 );
seconds OF re... | Give a code snippet in #ALGOL_68
Task
Write a function or program which:
takes a positive integer representing a duration in seconds as input (e.g., 100), and
returns a string which shows the same duration decomposed into:
weeks,
days,
hours,
minutes, and
seconds.
This is detailed below (e.... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Find_limit_of_recursion | Find limit of recursion | Find limit of recursion is part of Short Circuit's Console Program Basics selection.
Task
Find the limit of recursion.
| #Inform_7 | Inform 7 | Home is a room.
When play begins: recurse 0.
To recurse (N - number):
say "[N].";
recurse N + 1. | Give a code snippet in #Inform_7
Find limit of recursion is part of Short Circuit's Console Program Basics selection.
Task
Find the limit of recursion.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Bitwise_operations | Bitwise operations |
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 |... | #Rust | Rust | fn main() {
let a: u8 = 105;
let b: u8 = 91;
println!("a = {:0>8b}", a);
println!("b = {:0>8b}", b);
println!("a | b = {:0>8b}", a | b);
println!("a & b = {:0>8b}", a & b);
println!("a ^ b = {:0>8b}", a ^ b);
println!("!a = {:0>8b}", !a);
println!("a << 3 = {:0>8b}",... | Give a code snippet in #Rust
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
C... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Check_that_file_exists | Check that file exists | Task
Verify that a file called input.txt and a directory called docs exist.
This should be done twice:
once for the current working directory, and
once for a file and a directory in the filesystem root.
Optional criteria (May 2015): verify it works with:
zero-length files
an ... | #VBA | VBA |
Option Explicit
Sub Main_File_Exists()
Dim myFile As String, myDirectory As String
myFile = "Abdu'l-Bahá.txt"
myDirectory = "C:\"
Debug.Print File_Exists(myFile, myDirectory)
End Sub
Function File_Exists(F As String, D As String) As Boolean
If F = "" Then
File_Exists = False
Else
... | Give a code snippet in #VBA
Task
Verify that a file called input.txt and a directory called docs exist.
This should be done twice:
once for the current working directory, and
once for a file and a directory in the filesystem root.
Optional criteria (May 2015): verify it works with:... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Delete_a_file | Delete a file | Task
Delete a file called "input.txt" and delete a directory called "docs".
This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root.
| #Ruby | Ruby | File.delete("output.txt", "/output.txt")
Dir.delete("docs")
Dir.delete("/docs") | Give a code snippet in #Ruby
Task
Delete a file called "input.txt" and delete a directory called "docs".
This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Literals/Integer | Literals/Integer | Some programming languages have ways of expressing integer literals in bases other than the normal base ten.
Task
Show how integer literals can be expressed in as many bases as your language allows.
Note: this should not involve the calling of any functions/methods, but should be interpreted by the compiler or... | #Rust | Rust | 10 // Decimal
0b10 // Binary
0x10 // Hexadecimal
0o10 // Octal
1_000 // Underscores may appear anywhere in the numeric literal for clarity
10_i32 // The type (in this case i32, a 32-bit signed integer) may also be appended.
10i32 // With or without underscores | Give a code snippet in #Rust
Some programming languages have ways of expressing integer literals in bases other than the normal base ten.
Task
Show how integer literals can be expressed in as many bases as your language allows.
Note: this should not involve the calling of any functions/methods, but should be ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Non-decimal_radices/Input | Non-decimal radices/Input | It is common to have a string containing a number written in some format, with the most common ones being decimal, hexadecimal, octal and binary. Such strings are found in many places (user interfaces, configuration files, XML data, network protocols, etc.)
This task requires parsing of such a string (which may be ass... | #C | C | #include <stdio.h>
int main()
{
int num;
sscanf("0123459", "%d", &num);
printf("%d\n", num); /* prints 123459 */
sscanf("abcf123", "%x", &num);
printf("%d\n", num); /* prints 180154659 */
sscanf("7651", "%o", &num);
printf("%d\n", num); /* prints 4009 */
/* binary not supported */
return 0... | Give a code snippet in #C
It is common to have a string containing a number written in some format, with the most common ones being decimal, hexadecimal, octal and binary. Such strings are found in many places (user interfaces, configuration files, XML data, network protocols, etc.)
This task requires parsing of such... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sort_using_a_custom_comparator | Sort using a custom comparator |
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
... | #min | min | ("Here" "are" "some" "sample" "strings" "to" "be" "sorted")
(((length) (length)) spread <) sort print | Give a code snippet in #min
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 |
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