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 |
|---|---|---|---|---|---|
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
| #Icon_and_Unicon | Icon and Unicon | procedure main(arglist)
if *envars = 0 then envars := ["HOME", "TRACE", "BLKSIZE","STRSIZE","COEXPSIZE","MSTKSIZE", "IPATH","LPATH","NOERRBUF"]
every v := !sort(envars) do
write(v," = ",image(getenv(v))|"* not set *")
end |
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
| #J | J | 2!:5'HOME' |
http://rosettacode.org/wiki/Esthetic_numbers | Esthetic numbers | An esthetic number is a positive integer where every adjacent digit differs from its neighbour by 1.
E.G.
12 is an esthetic number. One and two differ by 1.
5654 is an esthetic number. Each digit is exactly 1 away from its neighbour.
890 is not an esthetic number. Nine and zero differ by 9.
These examples are n... | #Python | Python | from collections import deque
from itertools import dropwhile, islice, takewhile
from textwrap import wrap
from typing import Iterable, Iterator
Digits = str # Alias for the return type of to_digits()
def esthetic_nums(base: int) -> Iterator[int]:
"""Generate the esthetic number sequence for a given base
... |
http://rosettacode.org/wiki/Euler%27s_sum_of_powers_conjecture | Euler's sum of powers conjecture | There is a conjecture in mathematics that held for over two hundred years before it was disproved by the finding of a counterexample in 1966 by Lander and Parkin.
Euler's (disproved) sum of powers conjecture
At least k positive kth powers are required to sum to a kth power,
except for the trivial case... | #Elixir | Elixir | defmodule Euler do
def sum_of_power(max \\ 250) do
{p5, sum2} = setup(max)
sk = Enum.sort(Map.keys(sum2))
Enum.reduce(Enum.sort(Map.keys(p5)), Map.new, fn p,map ->
sum(sk, p5, sum2, p, map)
end)
end
defp setup(max) do
Enum.reduce(1..max, {%{}, %{}}, fn i,{p5,sum2} ->
i5 = i*i*i*i... |
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... | #Neko | Neko | var factorial = function(number) {
var i = 1;
var result = 1;
while(i <= number) {
result *= i;
i += 1;
}
return result;
};
$print(factorial(10)); |
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... | #Befunge | Befunge | &2%52**"E"+,@ |
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... | #BQN | BQN |
odd ← 2⊸|
!0 ≡ odd 12
!1 ≡ odd 31 |
http://rosettacode.org/wiki/Euler_method | Euler method | Euler's method numerically approximates solutions of first-order ordinary differential equations (ODEs) with a given initial value. It is an explicit method for solving initial value problems (IVPs), as described in the wikipedia page.
The ODE has to be provided in the following form:
d
y
(
t
)
d
t
=
f... | #PicoLisp | PicoLisp | (load "@lib/math.l")
(de euler (F Y A B H)
(while (> B A)
(prinl (round A) " " (round Y))
(inc 'Y (*/ H (F A Y) 1.0))
(inc 'A H) ) )
(de newtonCoolingLaw (A B)
(*/ -0.07 (- B 20.) 1.0) )
(euler newtonCoolingLaw 100.0 0 100.0 2.0)
(euler newtonCoolingLaw 100.0 0 100.0 5.0)
(euler newtonCool... |
http://rosettacode.org/wiki/Euler_method | Euler method | Euler's method numerically approximates solutions of first-order ordinary differential equations (ODEs) with a given initial value. It is an explicit method for solving initial value problems (IVPs), as described in the wikipedia page.
The ODE has to be provided in the following form:
d
y
(
t
)
d
t
=
f... | #PL.2FI | PL/I | test: procedure options (main); /* 3 December 2012 */
declare (x, y, z) float;
declare (T0 initial (100), Tr initial (20)) float;
declare k float initial (0.07);
declare t fixed binary;
declare h fixed binary;
x, y, z = T0;
/* Step size is 2 seconds */
h = 2;
put skip data (h);
put ski... |
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... | #Golfscript | Golfscript | ;5 3 # Set up demo input
{),(;{*}*}:f; # Define a factorial function
.f@.f@/\@-f/ |
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... | #Groovy | Groovy | def factorial = { x ->
assert x > -1
x == 0 ? 1 : (1..x).inject(1G) { BigInteger product, BigInteger factor -> product *= factor }
}
def combinations = { n, k ->
assert k >= 0
assert n >= k
factorial(n).intdiv(factorial(k)*factorial(n-k))
} |
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 ... | #Xojo | Xojo | Function fibo(n As Integer) As UInt64
Dim noOne As UInt64 = 1
Dim noTwo As UInt64 = 1
Dim sum As UInt64
For i As Integer = 3 To n
sum = noOne + noTwo
noTwo = noOne
noOne = sum
Next
Return noOne
End Function |
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
| #Ruby | Ruby | def entropy(s)
counts = s.each_char.tally
size = s.size.to_f
counts.values.reduce(0) do |entropy, count|
freq = count / size
entropy - freq * Math.log2(freq)
end
end
s = File.read(__FILE__)
p entropy(s)
|
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(|... |
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
| #Sidef | Sidef | func entropy(s) {
[0,
s.chars.freq.values.map {|c|
var f = c/s.len
f * f.log2
}...
]«-»
}
say entropy(File(__FILE__).open_r.slurp) |
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
| #Tcl | Tcl | proc entropy {str} {
set log2 [expr log(2)]
foreach char [split $str ""] {dict incr counts $char}
set entropy 0.0
foreach count [dict values $counts] {
set freq [expr {$count / double([string length $str])}]
set entropy [expr {$entropy - $freq * log($freq)/$log2}]
}
return $entropy
}
puts [f... |
http://rosettacode.org/wiki/Elliptic_curve_arithmetic | Elliptic curve arithmetic | Elliptic curves are sometimes used in cryptography as a way to perform digital signatures.
The purpose of this task is to implement a simplified (without modular arithmetic) version of the elliptic curve arithmetic which is required by the elliptic curve DSA protocol.
In a nutshell, an elliptic curve is a... | #C | C | #include <stdio.h>
#include <math.h>
#define C 7
typedef struct { double x, y; } pt;
pt zero(void) { return (pt){ INFINITY, INFINITY }; }
// should be INFINITY, but numeric precision is very much in the way
int is_zero(pt p) { return p.x > 1e20 || p.x < -1e20; }
pt neg(pt p) { return (pt){ p.x, -p.y }; }
pt d... |
http://rosettacode.org/wiki/Enumerations | Enumerations | Task
Create an enumeration of constants with and without explicit values.
| #Factor | Factor | IN: scratchpad { "sun" "mon" "tue" "wed" "thur" "fri" "sat" } <enum>
--- Data stack:
T{ enum f ~array~ }
IN: scratchpad [ 1 swap at ] [ keys ] bi
--- Data stack:
"mon"
{ 0 1 2 3 4 5 6 } |
http://rosettacode.org/wiki/Enumerations | Enumerations | Task
Create an enumeration of constants with and without explicit values.
| #Fantom | Fantom |
// create an enumeration with named constants
enum class Fruits { apple, banana, orange }
|
http://rosettacode.org/wiki/Enumerations | Enumerations | Task
Create an enumeration of constants with and without explicit values.
| #Forth | Forth | 0 CONSTANT apple
1 CONSTANT banana
2 CONSTANT cherry
... |
http://rosettacode.org/wiki/Elementary_cellular_automaton/Random_Number_Generator | Elementary cellular automaton/Random Number Generator | Rule 30 is considered to be chaotic enough to generate good pseudo-random numbers. As a matter of fact, rule 30 is used by the Mathematica software for its default random number generator.
Steven Wolfram's recommendation for random number generation from rule 30 consists in extracting successive bits in a fixed positi... | #11l | 11l | V n = 64
F pow2(x)
R UInt64(1) << x
F evolve(UInt64 =state; rule)
L 10
V b = UInt64(0)
L(q) (7 .. 0).step(-1)
V st = state
b [|]= (st [&] 1) << q
state = 0
L(i) 0 .< :n
V t = ((st >> (i - 1)) [|] (st << (:n + 1 - i))) [&] 7
I (rule [&] po... |
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... | #8th | 8th | "" var, str |
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... | #AArch64_Assembly | AArch64 Assembly | str: .asciz "" |
http://rosettacode.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm | Elliptic Curve Digital Signature Algorithm | Elliptic curves.
An elliptic curve E over ℤp (p ≥ 5) is defined by an equation of the form
y^2 = x^3 + ax + b, where a, b ∈ ℤp and the discriminant ≢ 0 (mod p),
together with a special point 𝒪 called the point at infinity.
The set E(ℤp) consists of all points (x, y), with x, y ∈ ℤp,
which satisfy the above defining eq... | #Go | Go | package main
import (
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rand"
"crypto/sha256"
"encoding/binary"
"fmt"
"log"
)
func check(err error) {
if err != nil {
log.Fatal(err)
}
}
func main() {
priv, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
check(err)
... |
http://rosettacode.org/wiki/Empty_directory | Empty directory | Starting with a path to some directory, determine whether the directory is empty.
An empty directory contains no files nor subdirectories.
With Unix or Windows systems, every directory contains an entry for “.” and almost every directory contains “..” (except for a root directory); an empty directory contains no other... | #AutoHotkey | AutoHotkey | MsgBox % isDir_empty(A_ScriptDir)?"true":"false"
isDir_empty(p) {
Loop, %p%\* , 1
return 0
return 1
} |
http://rosettacode.org/wiki/Empty_directory | Empty directory | Starting with a path to some directory, determine whether the directory is empty.
An empty directory contains no files nor subdirectories.
With Unix or Windows systems, every directory contains an entry for “.” and almost every directory contains “..” (except for a root directory); an empty directory contains no other... | #AWK | AWK |
# syntax: GAWK -f EMPTY_DIRECTORY.AWK
BEGIN {
n = split("C:\\TEMP3,C:\\NOTHERE,C:\\AWK\\FILENAME,C:\\WINDOWS",arr,",")
for (i=1; i<=n; i++) {
printf("'%s' %s\n",arr[i],is_dir(arr[i]))
}
exit(0)
}
function is_dir(path, cmd,dots,entries,msg,rec,valid_dir) {
cmd = sprintf("DIR %s 2>NUL",path) ... |
http://rosettacode.org/wiki/Empty_program | Empty program | Task
Create the simplest possible program that is still considered "correct."
| #68000_Assembly | 68000 Assembly | forever:
MOVE.B D0,$300001
JMP forever |
http://rosettacode.org/wiki/Empty_program | Empty program | Task
Create the simplest possible program that is still considered "correct."
| #8051_Assembly | 8051 Assembly | ORG RESET
jmp $ |
http://rosettacode.org/wiki/Enforced_immutability | Enforced immutability | Task
Demonstrate any means your language has to prevent the modification of values, or to create objects that cannot be modified after they have been created.
| #Go | Go | package main
func main() {
s := "immutable"
s[0] = 'a'
} |
http://rosettacode.org/wiki/Enforced_immutability | Enforced immutability | Task
Demonstrate any means your language has to prevent the modification of values, or to create objects that cannot be modified after they have been created.
| #Haskell | Haskell | pi = 3.14159
msg = "Hello World" |
http://rosettacode.org/wiki/Enforced_immutability | Enforced immutability | Task
Demonstrate any means your language has to prevent the modification of values, or to create objects that cannot be modified after they have been created.
| #Icon_and_Unicon | Icon and Unicon | $define "1234" |
http://rosettacode.org/wiki/Enforced_immutability | Enforced immutability | Task
Demonstrate any means your language has to prevent the modification of values, or to create objects that cannot be modified after they have been created.
| #J | J | B=: A=: 'this is a test'
A=: '*' 2 3 5 7} A
A
th** *s*a test
B
this is a test |
http://rosettacode.org/wiki/Entropy | Entropy | Task
Calculate the Shannon entropy H of a given input string.
Given the discrete random variable
X
{\displaystyle X}
that is a string of
N
{\displaystyle N}
"symbols" (total characters) consisting of
n
{\displaystyle n}
different characters (n=2 for binary), the Shannon entropy of X in bit... | #BASIC | BASIC | 10 DEF FN L(X)=LOG(X)/LOG(2)
20 S$="1223334444"
30 U$=""
40 FOR I=1 TO LEN(S$)
50 K=0
60 FOR J=1 TO LEN(U$)
70 IF MID$(U$,J,1)=MID$(S$,I,1) THEN K=1
80 NEXT J
90 IF K=0 THEN U$=U$+MID$(S$,I,1)
100 NEXT I
110 DIM R(LEN(U$)-1)
120 FOR I=1 TO LEN(U$)
130 C=0
140 FOR J=1 TO LEN(S$)
150 IF MID$(U$,I,1)=MID$(S$,J,1) THEN C=C... |
http://rosettacode.org/wiki/Entropy | Entropy | Task
Calculate the Shannon entropy H of a given input string.
Given the discrete random variable
X
{\displaystyle X}
that is a string of
N
{\displaystyle N}
"symbols" (total characters) consisting of
n
{\displaystyle n}
different characters (n=2 for binary), the Shannon entropy of X in bit... | #BBC_BASIC | BBC BASIC | REM >entropy
PRINT FNentropy("1223334444")
END
:
DEF FNentropy(x$)
LOCAL unique$, count%, n%, ratio(), u%, i%, j%
unique$ = ""
n% = LEN x$
FOR i% = 1 TO n%
IF INSTR(unique$, MID$(x$, i%, 1)) = 0 THEN unique$ += MID$(x$, i%, 1)
NEXT
u% = LEN unique$
DIM ratio(u% - 1)
FOR i% = 1 TO u%
count% = 0
FOR j% = 1 TO n%
... |
http://rosettacode.org/wiki/Ethiopian_multiplication | Ethiopian multiplication | Ethiopian multiplication is a method of multiplying integers using only addition, doubling, and halving.
Method:
Take two numbers to be multiplied and write them down at the top of two columns.
In the left-hand column repeatedly halve the last number, discarding any remainders, and write the result below the last ... | #Bracmat | Bracmat | ( (halve=.div$(!arg.2))
& (double=.2*!arg)
& (isEven=.mod$(!arg.2):0)
& ( mul
= a b as bs newbs result
. !arg:(?as.?bs)
& whl
' ( !as:? (%@:~1:?a)
& !as halve$!a:?as
& !bs:? %@?b
& !bs double$!b:?bs
)
& :?newbs
& whl
' ( !as:%@?a ?a... |
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}
... | #Factor | Factor | USE: math.vectors
: accum-left ( seq id quot -- seq ) accumulate nip ; inline
: accum-right ( seq id quot -- seq ) [ <reversed> ] 2dip accum-left <reversed> ; inline
: equilibrium-indices ( seq -- inds )
0 [ + ] [ accum-left ] [ accum-right ] 3bi [ = ] 2map
V{ } swap dup length iota [ [ suffix ] curry [ ] if ] 2eac... |
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}
... | #Fortran | Fortran | program Equilibrium
implicit none
integer :: array(7) = (/ -7, 1, 5, 2, -4, 3, 0 /)
call equil_index(array)
contains
subroutine equil_index(a)
integer, intent(in) :: a(:)
integer :: i
do i = 1, size(a)
if(sum(a(1:i-1)) == sum(a(i+1:size(a)))) write(*,*) i
end do
end subroutine
end program |
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
| #Java | Java | System.getenv("HOME") // get env var
System.getenv() // get the entire environment as a Map of keys to values |
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
| #JavaScript | JavaScript | var shell = new ActiveXObject("WScript.Shell");
var env = shell.Environment("PROCESS");
WScript.echo('SYSTEMROOT=' + env.item('SYSTEMROOT')); |
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
| #Joy | Joy | "HOME" getenv. |
http://rosettacode.org/wiki/Esthetic_numbers | Esthetic numbers | An esthetic number is a positive integer where every adjacent digit differs from its neighbour by 1.
E.G.
12 is an esthetic number. One and two differ by 1.
5654 is an esthetic number. Each digit is exactly 1 away from its neighbour.
890 is not an esthetic number. Nine and zero differ by 9.
These examples are n... | #Raku | Raku | use Lingua::EN::Numbers;
sub esthetic($base = 10) {
my @s = ^$base .map: -> \s {
((s - 1).base($base) if s > 0), ((s + 1).base($base) if s < $base - 1)
}
flat [ (1 .. $base - 1)».base($base) ],
{ [ flat .map: { $_ xx * Z~ flat @s[.comb.tail.parse-base($base)] } ] } … *
}
for 2 .. 16 -> $b ... |
http://rosettacode.org/wiki/Euler%27s_sum_of_powers_conjecture | Euler's sum of powers conjecture | There is a conjecture in mathematics that held for over two hundred years before it was disproved by the finding of a counterexample in 1966 by Lander and Parkin.
Euler's (disproved) sum of powers conjecture
At least k positive kth powers are required to sum to a kth power,
except for the trivial case... | #ERRE | ERRE | PROGRAM EULERO
CONST MAX=250
!$DOUBLE
FUNCTION POW5(X)
POW5=X*X*X*X*X
END FUNCTION
!$INCLUDE="PC.LIB"
BEGIN
CLS
FOR X0=1 TO MAX DO
FOR X1=1 TO X0 DO
FOR X2=1 TO X1 DO
FOR X3=1 TO X2 DO
LOCATE(3,1) PRINT(X0;X1;X2;X3)
SUM=POW5(X0)+POW5(X1)+POW5(X2)+P... |
http://rosettacode.org/wiki/Factorial | Factorial | Definitions
The factorial of 0 (zero) is defined as being 1 (unity).
The Factorial Function of a positive integer, n, is defined as the product of the sequence:
n, n-1, n-2, ... 1
Task
Write a function to return the factorial of a number.
Solutions can be iterat... | #Nemerle | Nemerle | using System;
using System.Console;
module Program
{
Main() : void
{
WriteLine("Factorial of which number?");
def number = long.Parse(ReadLine());
WriteLine("Using Fold : Factorial of {0} is {1}", number, FactorialFold(number));
WriteLine("Using Match: Factorial of {0} is {1}", number, Fac... |
http://rosettacode.org/wiki/Even_or_odd | Even or odd | Task
Test whether an integer is even or odd.
There is more than one way to solve this task:
Use the even and odd predicates, if the language provides them.
Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd.
Divide i by 2. The remainder equals... | #Bracmat | Bracmat | ( ( even
=
. @( !arg
: ?
[-2
( 0
| 2
| 4
| 6
| 8
)
)
)
& (odd=.~(even$!arg))
& ( eventest
=
. out
$ (!arg is (even$!arg&|not) even)
)
& ( oddtest
=
. out
$ (!arg is (odd$!arg&|not) odd)
)... |
http://rosettacode.org/wiki/Even_or_odd | Even or odd | Task
Test whether an integer is even or odd.
There is more than one way to solve this task:
Use the even and odd predicates, if the language provides them.
Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd.
Divide i by 2. The remainder equals... | #Brainf.2A.2A.2A | Brainf*** | ,[>,----------] Read until newline
++< Get a 2 and move into position
[->-[>+>>]> Do
[+[-<+>]>+>>] divmod
<<<<<] magic
>[-]<++++++++ Clear and get an 8
[>++++++<-] to get a 48
>[>+<-]>. to get n % 2 to ASCII and print |
http://rosettacode.org/wiki/Euler_method | Euler method | Euler's method numerically approximates solutions of first-order ordinary differential equations (ODEs) with a given initial value. It is an explicit method for solving initial value problems (IVPs), as described in the wikipedia page.
The ODE has to be provided in the following form:
d
y
(
t
)
d
t
=
f... | #PowerShell | PowerShell |
function euler (${f}, ${y}, $y0, $t0, $tEnd) {
function f-euler ($tn, $yn, $h) {
$yn + $h*(f $tn $yn)
}
function time ($t0, $h, $tEnd) {
$end = [MATH]::Floor(($tEnd - $t0)/$h)
foreach ($_ in 0..$end) { $_*$h + $t0 }
}
$time = time $t0 10 $tEnd
$time5 = time $t0 5 $tE... |
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... | #GW-BASIC | GW-BASIC | 10 REM BINOMIAL CALCULATOR
20 INPUT "N? ", N
30 INPUT "P? ", P
40 GOSUB 70
50 PRINT C
60 END
70 C = 0
80 IF N < 0 OR P<0 OR P > N THEN RETURN
90 IF P < N\2 THEN P = N - P
100 C = 1
110 FOR I = N TO P+1 STEP -1
120 C=C*I
130 NEXT I
140 FOR I = 1 TO N-P
150 C=C/I
160 NEXT I
170 RETURN |
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 ... | #XPL0 | XPL0 | func Fib1(N); \Return Nth Fibonacci number using iteration
int N;
int Fn, F0, F1;
[F0:= 0; F1:= 1; Fn:= N;
while N > 1 do
[Fn:= F0 + F1;
F0:= F1;
F1:= Fn;
N:= N-1;
];
return Fn;
];
func Fib2(N); \Return Nth Fibonacci number using recursion
int N;
return if N < 2 then N el... |
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
| #Vlang | Vlang | import os
import math
fn main() {
println("Binary file entropy: ${entropy(os.args[0])?}")
}
fn entropy(file string) ?f64 {
d := os.read_bytes(file)?
mut f := [256]f64{}
for b in d {
f[b]++
}
mut hm := 0.0
for c in f {
if c > 0 {
hm += c * math.log2(c)
... |
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
| #Wren | Wren | import "os" for Process
import "io" for File
var args = Process.allArguments
var s = File.read(args[1]).trim()
var m = {}
for (c in s) {
var d = m[c]
m[c] = (d) ? d + 1 : 1
}
var hm = 0
for (k in m.keys) {
var c = m[k]
hm = hm + c * c.log2
}
var l = s.count
System.print(l.log2 - hm/l) |
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
| #zkl | zkl | fcn entropy(text){
text.pump(Void,fcn(c,freq){ c=c.toAsc(); freq[c]=freq[c]+1; freq }
.fp1((0).pump(256,List,(0.0).create.fp(0)).copy()))
.filter() // remove all zero entries
.apply('/(text.len())) // (num of char)/len
.apply(fcn(p){-p*p.log()}) // |p*ln(p)|
.sum(0.0)/(2.0).log(); /... |
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... | #11l | 11l | F reversed(Int =n)
V result = 0
L
result = 10 * result + n % 10
n I/= 10
I n == 0
R result
V limit = 1'000'000
V is_prime = [0B] * 2 [+] [1B] * (limit - 1)
L(n) 0 .< Int(limit ^ 0.5 + 1.5)
I is_prime[n]
L(i) (n * n .< limit + 1).step(n)
is_prime[i] = 0B
F is_emirp(... |
http://rosettacode.org/wiki/Elliptic_curve_arithmetic | Elliptic curve arithmetic | Elliptic curves are sometimes used in cryptography as a way to perform digital signatures.
The purpose of this task is to implement a simplified (without modular arithmetic) version of the elliptic curve arithmetic which is required by the elliptic curve DSA protocol.
In a nutshell, an elliptic curve is a... | #C.2B.2B | C++ | #include <cmath>
#include <iostream>
using namespace std;
// define a type for the points on the elliptic curve that behaves
// like a built in type.
class EllipticPoint
{
double m_x, m_y;
static constexpr double ZeroThreshold = 1e20;
static constexpr double B = 7; // the 'b' in y^2 = x^3 + a * x + b
... |
http://rosettacode.org/wiki/Enumerations | Enumerations | Task
Create an enumeration of constants with and without explicit values.
| #Fortran | Fortran | enum, bind(c)
enumerator :: one=1, two, three, four, five
enumerator :: six, seven, nine=9
end enum |
http://rosettacode.org/wiki/Enumerations | Enumerations | Task
Create an enumeration of constants with and without explicit values.
| #Free_Pascal | Free Pascal | ' FB 1.05.0 Win64
Enum Animals
Cat
Dog
Zebra
End Enum
Enum Dogs
Bulldog = 1
Terrier = 2
WolfHound = 4
End Enum
Print Cat, Dog, Zebra
Print Bulldog, Terrier, WolfHound
Sleep |
http://rosettacode.org/wiki/Enumerations | Enumerations | Task
Create an enumeration of constants with and without explicit values.
| #FreeBASIC | FreeBASIC | ' FB 1.05.0 Win64
Enum Animals
Cat
Dog
Zebra
End Enum
Enum Dogs
Bulldog = 1
Terrier = 2
WolfHound = 4
End Enum
Print Cat, Dog, Zebra
Print Bulldog, Terrier, WolfHound
Sleep |
http://rosettacode.org/wiki/Elementary_cellular_automaton/Random_Number_Generator | Elementary cellular automaton/Random Number Generator | Rule 30 is considered to be chaotic enough to generate good pseudo-random numbers. As a matter of fact, rule 30 is used by the Mathematica software for its default random number generator.
Steven Wolfram's recommendation for random number generation from rule 30 consists in extracting successive bits in a fixed positi... | #C | C | #include <stdio.h>
#include <limits.h>
typedef unsigned long long ull;
#define N (sizeof(ull) * CHAR_BIT)
#define B(x) (1ULL << (x))
void evolve(ull state, int rule)
{
int i, p, q, b;
for (p = 0; p < 10; p++) {
for (b = 0, q = 8; q--; ) {
ull st = state;
b |= (st&1) << q;
for (state = i = 0; i < N;... |
http://rosettacode.org/wiki/Elementary_cellular_automaton/Random_Number_Generator | Elementary cellular automaton/Random Number Generator | Rule 30 is considered to be chaotic enough to generate good pseudo-random numbers. As a matter of fact, rule 30 is used by the Mathematica software for its default random number generator.
Steven Wolfram's recommendation for random number generation from rule 30 consists in extracting successive bits in a fixed positi... | #C.2B.2B | C++ | #include <bitset>
#include <stdio.h>
#define SIZE 80
#define RULE 30
#define RULE_TEST(x) (RULE & 1 << (7 & (x)))
void evolve(std::bitset<SIZE> &s) {
int i;
std::bitset<SIZE> t(0);
t[SIZE-1] = RULE_TEST( s[0] << 2 | s[SIZE-1] << 1 | s[SIZE-2] );
t[ 0] = RULE_TEST( ... |
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... | #ACL2 | ACL2 | (= (length str) 0) |
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... | #Action.21 | Action! | PROC CheckIsEmpty(CHAR ARRAY s)
PrintF("'%S' is empty? ",s)
IF s(0)=0 THEN
PrintE("True")
ELSE
PrintE("False")
FI
RETURN
PROC Main()
CHAR ARRAY str1,str2
str1=""
str2="text"
CheckIsEmpty(str1)
CheckIsEmpty(str2)
RETURN |
http://rosettacode.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm | Elliptic Curve Digital Signature Algorithm | Elliptic curves.
An elliptic curve E over ℤp (p ≥ 5) is defined by an equation of the form
y^2 = x^3 + ax + b, where a, b ∈ ℤp and the discriminant ≢ 0 (mod p),
together with a special point 𝒪 called the point at infinity.
The set E(ℤp) consists of all points (x, y), with x, y ∈ ℤp,
which satisfy the above defining eq... | #Julia | Julia | module ToyECDSA
using SHA
import Base.in, Base.==, Base.+, Base.*
export ECDSA_Key, ECDSA_Public_Key, genkey, ECDSA_sign, isverifiedECDSA
# T will be BigInt in most applications
struct CurveFP{T}
p::T
a::T
b::T
CurveFP(p, a::T, b::T) where T <: Number = new{T}(p, a, b)
end
struct PointEC{T}
... |
http://rosettacode.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm | Elliptic Curve Digital Signature Algorithm | Elliptic curves.
An elliptic curve E over ℤp (p ≥ 5) is defined by an equation of the form
y^2 = x^3 + ax + b, where a, b ∈ ℤp and the discriminant ≢ 0 (mod p),
together with a special point 𝒪 called the point at infinity.
The set E(ℤp) consists of all points (x, y), with x, y ∈ ℤp,
which satisfy the above defining eq... | #Nim | Nim | import math, random, strformat
const
MaxN = 1073741789 # Maximum modulus.
MaxR = MaxN + 65536 # Maximum order "g".
Infinity = int64.high # Symbolic infinity.
type
Point = tuple[x, y: int64]
Curve = object
a, b: int64
n: int64
g: Point
r: int64
Pair = tuple[a, b: int64]
... |
http://rosettacode.org/wiki/Empty_directory | Empty directory | Starting with a path to some directory, determine whether the directory is empty.
An empty directory contains no files nor subdirectories.
With Unix or Windows systems, every directory contains an entry for “.” and almost every directory contains “..” (except for a root directory); an empty directory contains no other... | #BaCon | BaCon | FUNCTION check$(dir$)
IF FILEEXISTS(dir$) THEN
RETURN IIF$(LEN(WALK$(dir$, 127, ".+", FALSE)), " is NOT empty.", " is empty." )
ELSE
RETURN " doesn't exist."
ENDIF
ENDFUNCTION
dir$ = "bla"
PRINT "Directory '", dir$, "'", check$(dir$)
dir$ = "/mnt"
PRINT "Directory '", dir$, "'", chec... |
http://rosettacode.org/wiki/Empty_directory | Empty directory | Starting with a path to some directory, determine whether the directory is empty.
An empty directory contains no files nor subdirectories.
With Unix or Windows systems, every directory contains an entry for “.” and almost every directory contains “..” (except for a root directory); an empty directory contains no other... | #Batch_File | Batch File | @echo off
if "%~1"=="" exit /b 3
set "samp_path=%~1"
set "tst_var="
%== Store the current directory of the CMD ==%
for /f %%T in ('cd') do set curr_dir=%%T
%== Go to the samp_path ==%
cd %samp_path% 2>nul ||goto :folder_not_found
%== The current directory is now samp_path ==%
%== Scan what is inside samp_path... |
http://rosettacode.org/wiki/Empty_program | Empty program | Task
Create the simplest possible program that is still considered "correct."
| #8086_Assembly | 8086 Assembly | .model small ;.exe file
.stack 1024 ;this value doesn't matter, I chose this arbitrarily
.data
;not needed in an empty program
.code
mov ax,4C00h
int 21h ;exit this program and return to MS-DOS |
http://rosettacode.org/wiki/Empty_program | Empty program | Task
Create the simplest possible program that is still considered "correct."
| #AArch64_Assembly | AArch64 Assembly | .text
.global _start
_start:
mov x0, #0
mov x8, #93
svc #0 |
http://rosettacode.org/wiki/Enforced_immutability | Enforced immutability | Task
Demonstrate any means your language has to prevent the modification of values, or to create objects that cannot be modified after they have been created.
| #Java | Java | final int immutableInt = 4;
int mutableInt = 4;
mutableInt = 6; //this is fine
immutableInt = 6; //this is an error |
http://rosettacode.org/wiki/Enforced_immutability | Enforced immutability | Task
Demonstrate any means your language has to prevent the modification of values, or to create objects that cannot be modified after they have been created.
| #JavaScript | JavaScript | const pi = 3.1415;
const msg = "Hello World"; |
http://rosettacode.org/wiki/Enforced_immutability | Enforced immutability | Task
Demonstrate any means your language has to prevent the modification of values, or to create objects that cannot be modified after they have been created.
| #jq | jq |
["a", "b"] as $a | $a[0] = 1 as $b | $a |
http://rosettacode.org/wiki/Enforced_immutability | Enforced immutability | Task
Demonstrate any means your language has to prevent the modification of values, or to create objects that cannot be modified after they have been created.
| #Julia | Julia | const x = 1
x = π # ERROR: invalid ridefinition of constant x |
http://rosettacode.org/wiki/Entropy | Entropy | Task
Calculate the Shannon entropy H of a given input string.
Given the discrete random variable
X
{\displaystyle X}
that is a string of
N
{\displaystyle N}
"symbols" (total characters) consisting of
n
{\displaystyle n}
different characters (n=2 for binary), the Shannon entropy of X in bit... | #BQN | BQN | H ← -∘(+´⊢×2⋆⁼⊢)∘((+˝⊢=⌜⍷)÷≠)
H "1223334444" |
http://rosettacode.org/wiki/Entropy | Entropy | Task
Calculate the Shannon entropy H of a given input string.
Given the discrete random variable
X
{\displaystyle X}
that is a string of
N
{\displaystyle N}
"symbols" (total characters) consisting of
n
{\displaystyle n}
different characters (n=2 for binary), the Shannon entropy of X in bit... | #Burlesque | Burlesque | blsq ) "1223334444"F:u[vv^^{1\/?/2\/LG}m[?*++
1.8464393446710157 |
http://rosettacode.org/wiki/Ethiopian_multiplication | Ethiopian multiplication | Ethiopian multiplication is a method of multiplying integers using only addition, doubling, and halving.
Method:
Take two numbers to be multiplied and write them down at the top of two columns.
In the left-hand column repeatedly halve the last number, discarding any remainders, and write the result below the last ... | #BQN | BQN | Double ← 2⊸×
Halve ← ⌊÷⟜2
Odd ← 2⊸|
EMul ← {
times ← ↕⌈2⋆⁼𝕨
+´(Odd Halve⍟times 𝕨)/Double⍟times 𝕩
}
17 EMul 34 |
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}
... | #FreeBASIC | FreeBASIC | ' FB 1.05.0 Win64
Sub equilibriumIndices (a() As Integer, b() As Integer)
If UBound(a) = -1 Then Return '' empty array
Dim sum As Integer = 0
Dim count As Integer = 0
For i As Integer = LBound(a) To UBound(a) : sum += a(i) : Next
Dim sumLeft As Integer = 0, sumRight As Integer = 0
For i As Integer =... |
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
| #jq | jq | env.HOME |
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
| #jsish | jsish | /* Environment variables, in Jsi */
puts(Util.getenv("HOME"));
var environment = Util.getenv();
puts(environment.PATH); |
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
| #Julia | Julia | @show ENV["PATH"]
@show ENV["HOME"]
@show ENV["USER"] |
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
| #K | K | _getenv "HOME" |
http://rosettacode.org/wiki/Esthetic_numbers | Esthetic numbers | An esthetic number is a positive integer where every adjacent digit differs from its neighbour by 1.
E.G.
12 is an esthetic number. One and two differ by 1.
5654 is an esthetic number. Each digit is exactly 1 away from its neighbour.
890 is not an esthetic number. Nine and zero differ by 9.
These examples are n... | #REXX | REXX | /*REXX pgm lists a bunch of esthetic numbers in bases 2 ──► 16, & base 10 in two ranges.*/
parse arg baseL baseH range /*obtain optional arguments from the CL*/
if baseL=='' | baseL=="," then baseL= 2 /*Not specified? Then use the default.*/
if baseH=='' | baseH=="," then baseH=16 ... |
http://rosettacode.org/wiki/Euler%27s_sum_of_powers_conjecture | Euler's sum of powers conjecture | There is a conjecture in mathematics that held for over two hundred years before it was disproved by the finding of a counterexample in 1966 by Lander and Parkin.
Euler's (disproved) sum of powers conjecture
At least k positive kth powers are required to sum to a kth power,
except for the trivial case... | #F.23 | F# |
//Find 4 integers whose 5th powers sum to the fifth power of an integer (Quickly!) - Nigel Galloway: April 23rd., 2015
let G =
let GN = Array.init<float> 250 (fun n -> (float n)**5.0)
let rec gng (n, i, g, e) =
match (n, i, g, e) with
| (250,_,_,_) -> "No Solution Found"
| (_,250,_,_) -> gng (n+1, n+1... |
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... | #NetRexx | NetRexx | /* NetRexx */
options replace format comments java crossref savelog symbols nobinary
numeric digits 64 -- switch to exponential format when numbers become larger than 64 digits
say 'Input a number: \-'
say
do
n_ = long ask -- Gets the number, must be an integer
say n_'! =' factorial(n_) '(using iteration)'
... |
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... | #Burlesque | Burlesque | 2.% |
http://rosettacode.org/wiki/Euler_method | Euler method | Euler's method numerically approximates solutions of first-order ordinary differential equations (ODEs) with a given initial value. It is an explicit method for solving initial value problems (IVPs), as described in the wikipedia page.
The ODE has to be provided in the following form:
d
y
(
t
)
d
t
=
f... | #PureBasic | PureBasic | Define.d
Prototype.d Func(Time, t)
Procedure.d Euler(*F.Func, y0, a, b, h)
Protected y=y0, t=a
While t<=b
PrintN(RSet(StrF(t,3),7)+" "+RSet(StrF(y,3),7))
y + h * *F(t,y)
t + h
Wend
EndProcedure
Procedure.d newtonCoolingLaw(Time, t)
ProcedureReturn -0.07*(t-20)
EndProcedure
If OpenConsole()
... |
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... | #Haskell | Haskell |
choose :: (Integral a) => a -> a -> a
choose n k = product [k+1..n] `div` product [1..n-k]
|
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... | #HicEst | HicEst | WRITE(Messagebox) BinomCoeff( 5, 3) ! displays 10
FUNCTION factorial( n )
factorial = 1
DO i = 1, n
factorial = factorial * i
ENDDO
END
FUNCTION BinomCoeff( n, k )
BinomCoeff = factorial(n)/factorial(n-k)/factorial(k)
END |
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 ... | #XQuery | XQuery | declare function local:fib($n as xs:integer) as xs:integer {
if($n < 2)
then $n
else local:fib($n - 1) + local:fib($n - 2)
}; |
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... | #Ada | Ada | with Ada.Text_IO, Miller_Rabin;
procedure Emirp_Gen is
type Num is range 0 .. 2**63-1; -- maximum for the gnat Ada compiler
MR_Iterations: constant Positive := 25;
-- the probability Pr[Is_Prime(N, MR_Iterations) = Probably_Prime]
-- is 1 for prime N and < 4**(-MR_Iterations) for composed N
... |
http://rosettacode.org/wiki/Elliptic_curve_arithmetic | Elliptic curve arithmetic | Elliptic curves are sometimes used in cryptography as a way to perform digital signatures.
The purpose of this task is to implement a simplified (without modular arithmetic) version of the elliptic curve arithmetic which is required by the elliptic curve DSA protocol.
In a nutshell, an elliptic curve is a... | #D | D | import std.stdio, std.math, std.string;
enum bCoeff = 7;
struct Pt {
double x, y;
@property static Pt zero() pure nothrow @nogc @safe {
return Pt(double.infinity, double.infinity);
}
@property bool isZero() const pure nothrow @nogc @safe {
return x > 1e20 || x < -1e20;
}
... |
http://rosettacode.org/wiki/Enumerations | Enumerations | Task
Create an enumeration of constants with and without explicit values.
| #FutureBasic | FutureBasic | window 1, @"Enumerations", (0,0,480,270)
begin enum 1
_apple
_banana
_cherry
end enum
begin enum
_appleExplicit = 10
_bananaExplicit = 15
_cherryExplicit = 30
end enum
print "_apple = "; _apple
print "_banana = "; _banana
print "_cherry = "; _cherry
print
print "_appleExplicit = "; _appleExplicit
print "_banan... |
http://rosettacode.org/wiki/Enumerations | Enumerations | Task
Create an enumeration of constants with and without explicit values.
| #Go | Go | const (
apple = iota
banana
cherry
) |
http://rosettacode.org/wiki/Enumerations | Enumerations | Task
Create an enumeration of constants with and without explicit values.
| #Groovy | Groovy | enum Fruit { apple, banana, cherry }
enum ValuedFruit {
apple(1), banana(2), cherry(3);
def value
ValuedFruit(val) {value = val}
String toString() { super.toString() + "(${value})" }
}
println Fruit.values()
println ValuedFruit.values() |
http://rosettacode.org/wiki/Elementary_cellular_automaton/Random_Number_Generator | Elementary cellular automaton/Random Number Generator | Rule 30 is considered to be chaotic enough to generate good pseudo-random numbers. As a matter of fact, rule 30 is used by the Mathematica software for its default random number generator.
Steven Wolfram's recommendation for random number generation from rule 30 consists in extracting successive bits in a fixed positi... | #D | D | import std.stdio, std.range, std.typecons;
struct CellularRNG {
private uint current;
private immutable uint rule;
private ulong state;
this(in ulong state_, in uint rule_) pure nothrow @safe @nogc {
this.state = state_;
this.rule = rule_;
popFront;
}
public enum bo... |
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... | #Ada | Ada | procedure Empty_String is
function Is_Empty(S: String) return Boolean is
begin
return S = ""; -- test that S is empty
end Is_Empty;
Empty: String := ""; -- Assign empty string
XXXXX: String := "Not Empty";
begin
if (not Is_Empty(Empty)) or Is_Empty(XXXXX) then
raise Program_Error wit... |
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... | #Aime | Aime | text s;
s = "";
if (length(s) == 0) {
...
}
if (length(s) != 0) {
....
} |
http://rosettacode.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm | Elliptic Curve Digital Signature Algorithm | Elliptic curves.
An elliptic curve E over ℤp (p ≥ 5) is defined by an equation of the form
y^2 = x^3 + ax + b, where a, b ∈ ℤp and the discriminant ≢ 0 (mod p),
together with a special point 𝒪 called the point at infinity.
The set E(ℤp) consists of all points (x, y), with x, y ∈ ℤp,
which satisfy the above defining eq... | #Perl | Perl | # 20200828 added Perl programming solution
use strict;
use warnings;
use Crypt::EC_DSA;
my $ecdsa = new Crypt::EC_DSA;
my ($pubkey, $prikey) = $ecdsa->keygen;
print "Message: ", my $msg = 'Rosetta Code', "\n";
print "Private Key :\n$prikey \n";
print "Public key :\n", $pubkey->x, "\n", $pubkey->y, "\n";
... |
http://rosettacode.org/wiki/Empty_directory | Empty directory | Starting with a path to some directory, determine whether the directory is empty.
An empty directory contains no files nor subdirectories.
With Unix or Windows systems, every directory contains an entry for “.” and almost every directory contains “..” (except for a root directory); an empty directory contains no other... | #BBC_BASIC | BBC BASIC | IF FNisdirectoryempty("C:\") PRINT "C:\ is empty" ELSE PRINT "C:\ is not empty"
IF FNisdirectoryempty("C:\temp") PRINT "C:\temp is empty" ELSE PRINT "C:\temp is not empty"
END
DEF FNisdirectoryempty(dir$)
LOCAL dir%, sh%, res%
DIM dir% LOCAL 317
IF RIGHT$(dir$)<>"\" dir$ += "... |
http://rosettacode.org/wiki/Empty_directory | Empty directory | Starting with a path to some directory, determine whether the directory is empty.
An empty directory contains no files nor subdirectories.
With Unix or Windows systems, every directory contains an entry for “.” and almost every directory contains “..” (except for a root directory); an empty directory contains no other... | #C | C | #include <stdio.h>
#include <dirent.h>
#include <string.h>
int dir_empty(const char *path)
{
struct dirent *ent;
int ret = 1;
DIR *d = opendir(path);
if (!d) {
fprintf(stderr, "%s: ", path);
perror("");
return -1;
}
while ((ent = readdir(d))) {
if (!strcmp(ent->d_name, ".") || !(strcmp(ent->d_name, ... |
http://rosettacode.org/wiki/Empty_program | Empty program | Task
Create the simplest possible program that is still considered "correct."
| #ABAP | ABAP |
report z_empty_program.
|
http://rosettacode.org/wiki/Empty_program | Empty program | Task
Create the simplest possible program that is still considered "correct."
| #Action.21 | Action! | |
http://rosettacode.org/wiki/Enforced_immutability | Enforced immutability | Task
Demonstrate any means your language has to prevent the modification of values, or to create objects that cannot be modified after they have been created.
| #Kotlin | Kotlin | // version 1.1.0
// constant top level property
const val N = 5
// read-only top level property
val letters = listOf('A', 'B', 'C', 'D', 'E') // 'listOf' creates here a List<Char) which is immutable
class MyClass { // MyClass is effectively immutable because it's only property is read-only
/... |
Subsets and Splits
Rosetta Code COBOL Python Hard Tasks
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Rosetta Code Task Comparisons
Identifies tasks common to both COBOL and Python languages that are described as having difficulty levels, revealing cross-language task similarities and providing useful comparative programming examples.
SQL Code Examples from Training Data
Retrieves raw SQL code examples for the SQL language, which is basic data retrieval without meaningful analysis or patterns.
SQL Code Examples from Training Data
Retrieves raw SQL code examples for the SQL language, which is basic filtering that shows what data looks like but doesn't provide meaningful analysis or patterns.
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Retrieves specific programming language names and codes from training data, providing basic filtering but limited analytical value beyond identifying these particular languages.