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/Sorting_algorithms/Heapsort | Sorting algorithms/Heapsort |
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
... | #Elixir | Elixir | defmodule Sort do
def heapSort(list) do
len = length(list)
heapify(List.to_tuple(list), div(len - 2, 2))
|> heapSort(len-1)
|> Tuple.to_list
end
defp heapSort(a, finish) when finish > 0 do
swap(a, 0, finish)
|> siftDown(0, finish-1)
|> heapSort(finish-1)
end
defp heapSort(a, _), ... | Give a code snippet in #Elixir
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 s... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Multisplit | Multisplit | It is often necessary to split a string into pieces
based on several different (potentially multi-character) separator strings,
while still retaining the information about which separators were present in the input.
This is particularly useful when doing small parsing tasks.
The task is to write code to demonstrate ... | #Phix | Phix | with javascript_semantics
procedure multisplit(string text, sequence delims)
integer k = 1, kdx
while true do
integer kmin = 0
for i=1 to length(delims) do
integer ki = match(delims[i],text,k)
if ki!=0 then
if kmin=0 or ki<kmin then
kmi... | Give a code snippet in #Phix
It is often necessary to split a string into pieces
based on several different (potentially multi-character) separator strings,
while still retaining the information about which separators were present in the input.
This is particularly useful when doing small parsing tasks.
The task is... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Catalan_numbers/Pascal%27s_triangle | Catalan numbers/Pascal's triangle | Task
Print out the first 15 Catalan numbers by extracting them from Pascal's triangle.
See
Catalan Numbers and the Pascal Triangle. This method enables calculation of Catalan Numbers using only addition and subtraction.
Catalan's Triangle for a Number Triangle that generates Catalan Numbers using onl... | #Ruby | Ruby | def catalan(num)
t = [0, 1] #grows as needed
(1..num).map do |i|
i.downto(1){|j| t[j] += t[j-1]}
t[i+1] = t[i]
(i+1).downto(1) {|j| t[j] += t[j-1]}
t[i+1] - t[i]
end
end
p catalan(15) | Give a code snippet in #Ruby
Task
Print out the first 15 Catalan numbers by extracting them from Pascal's triangle.
See
Catalan Numbers and the Pascal Triangle. This method enables calculation of Catalan Numbers using only addition and subtraction.
Catalan's Triangle for a Number Triangle that gener... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #BQN | BQN | •Show •args | Give a code snippet in #BQN
Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Smith_numbers | Smith numbers | Smith numbers are numbers such that the sum of the decimal digits of the integers that make up that number is the same as the sum of the decimal digits of its prime factors excluding 1.
By definition, all primes are excluded as they (naturally) satisfy this condition!
Smith numbers are also known as joke numbers.... | #JavaScript | JavaScript | (() => {
'use strict';
// isSmith :: Int -> Bool
const isSmith = n => {
const pfs = primeFactors(n);
return (1 < pfs.length || n !== pfs[0]) && (
sumDigits(n) === pfs.reduce(
(a, x) => a + sumDigits(x),
0
)
);
};
// ... | Give a code snippet in #JavaScript
Smith numbers are numbers such that the sum of the decimal digits of the integers that make up that number is the same as the sum of the decimal digits of its prime factors excluding 1.
By definition, all primes are excluded as they (naturally) satisfy this condition!
Smith numbers... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Stack | Stack |
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.
A stack is a container of elements with last in, first out access policy. Sometimes it also called LIFO.
The stack is accessed through its top.
The ba... | #ooRexx | ooRexx |
stack = .queue~of(123, 234) -- creates a stack with a couple of items
stack~push("Abc") -- pushing
value = stack~pull -- popping
value = stack~peek -- peeking
-- the is empty test
if stack~isEmpty then say "The stack is empty"
| Give a code snippet in #ooRexx
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.
A stack is a container of elements with last in, first out access policy. Sometimes it also called LIFO.
The stack is a... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Self-describing_numbers | Self-describing numbers | Self-describing numbers
You are encouraged to solve this task according to the task description, using any language you may know.
There are several so-called "self-describing" or "self-descriptive" integers.
An integer is said to be "self-describing" if it has the property that, when digit positions are labeled 0 to ... | #Java | Java | public class SelfDescribingNumbers{
public static boolean isSelfDescribing(int a){
String s = Integer.toString(a);
for(int i = 0; i < s.length(); i++){
String s0 = s.charAt(i) + "";
int b = Integer.parseInt(s0); // number of times i-th digit must occur for it to be a self des... | Give a code snippet in #Java
Self-describing numbers
You are encouraged to solve this task according to the task description, using any language you may know.
There are several so-called "self-describing" or "self-descriptive" integers.
An integer is said to be "self-describing" if it has the property that, when dig... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Spiral_matrix | Spiral matrix | Task
Produce a spiral array.
A spiral array is a square arrangement of the first N2 natural numbers, where the
numbers increase sequentially as you go around the edges of the array spiraling inwards.
For example, given 5, produce this array:
0 1 2 3 4
15 16 17 18 5
14 23 24 19 6
13 22 21 ... | #Nim | Nim | import sequtils, strutils
proc `$`(m: seq[seq[int]]): string =
for r in m:
let lg = result.len
for c in r:
result.addSep(" ", lg)
result.add align($c, 2)
result.add '\n'
proc spiral(n: Positive): seq[seq[int]] =
result = newSeqWith(n, repeat(-1, n))
var dx = 1
var dy, x, y = 0
for ... | Give a code snippet in #Nim
Task
Produce a spiral array.
A spiral array is a square arrangement of the first N2 natural numbers, where the
numbers increase sequentially as you go around the edges of the array spiraling inwards.
For example, given 5, produce this array:
0 1 2 3 4
15 16 17 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... | #Slate | Slate | ((1 to: 1000) reduce: [|:x :y | x + (y squared reciprocal as: Float)]). | Give a code snippet in #Slate
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/Order_by_pair_comparisons | Order by pair comparisons |
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
... | #Action.21 | Action! | DEFINE PTR="CARD"
PROC PrintArray(PTR ARRAY a BYTE size)
BYTE i
Put('[)
FOR i=0 TO size-1
DO
IF i>0 THEN Put(' ) FI
Print(a(i))
OD
Put(']) PutE()
RETURN
BYTE FUNC IsBefore(CHAR ARRAY a,b)
DEFINE NO_KEY="255"
DEFINE KEY_Y="43"
DEFINE KEY_N="35"
BYTE CH=$02FC ;Internal hardware value for... | Give a code snippet in #Action.21
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 |
Quic... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Euler%27s_constant_0.5772... | Euler's constant 0.5772... |
Task.
Compute the Euler constant 0.5772...
Discovered by Leonhard Euler around 1730, it is the most ubiquitous mathematical constant after pi and e, but appears more arcane than these.
Denoted gamma (γ), it measures the amount by which the partial sums of the harmonic series (the simplest diverging series) differ f... | #Picat | Picat | main =>
Gamma = 0.57721566490153286060651209008240,
println(Gamma),
foreach(N in 1..8)
G = e(10**N),
println([n=N,g=G,diff=G-Gamma])
end.
e(N) = [1.0/I : I in 1..N].sum-log(N). | Give a code snippet in #Picat
Task.
Compute the Euler constant 0.5772...
Discovered by Leonhard Euler around 1730, it is the most ubiquitous mathematical constant after pi and e, but appears more arcane than these.
Denoted gamma (γ), it measures the amount by which the partial sums of the harmonic series (the simp... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Compiler/AST_interpreter | Compiler/AST interpreter | An AST interpreter interprets an Abstract Syntax Tree (AST)
produced by a Syntax Analyzer.
Task[edit]
Take the AST output from the Syntax analyzer task, and interpret it as appropriate.
Refer to the Syntax analyzer task for details of the AST.
Loading the AST from the syntax analyzer is as simple as (pseudo code)
de... | #RATFOR | RATFOR | ######################################################################
#
# The Rosetta Code AST interpreter in Ratfor 77.
#
#
# In FORTRAN 77 and therefore in Ratfor 77, there is no way to specify
# that a value should be put on a call stack. Therefore there is no
# way to implement recursive algorithms in Ratfor 77 (a... | Give a code snippet in #RATFOR
An AST interpreter interprets an Abstract Syntax Tree (AST)
produced by a Syntax Analyzer.
Task[edit]
Take the AST output from the Syntax analyzer task, and interpret it as appropriate.
Refer to the Syntax analyzer task for details of the AST.
Loading the AST from the syntax analyzer i... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Exponentiation_with_infix_operators_in_(or_operating_on)_the_base | Exponentiation with infix operators in (or operating on) the base | (Many programming languages, especially those with extended─precision integer arithmetic, usually
support one of **, ^, ↑ or some such for exponentiation.)
Some languages treat/honor infix operators when performing exponentiation (raising
numbers to some power by the language's exponentiation operator, if ... | #Perl | Perl | use strict;
use warnings;
use Sub::Infix;
BEGIN { *e = infix { $_[0] ** $_[1] } }; # operator needs to be defined at compile time
my @eqns = ('1 + -$xOP$p', '1 + (-$x)OP$p', '1 + (-($x)OP$p)', '(1 + -$x)OP$p', '1 + -($xOP$p)');
for my $op ('**', '/e/', '|e|') {
for ( [-5, 2], [-5, 3], [5, 2], [5, 3] ) {
... | Give a code snippet in #Perl
(Many programming languages, especially those with extended─precision integer arithmetic, usually
support one of **, ^, ↑ or some such for exponentiation.)
Some languages treat/honor infix operators when performing exponentiation (raising
numbers to some power by the language's ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Unix/ls | Unix/ls | Task
Write a program that will list everything in the current folder, similar to:
the Unix utility “ls” [1] or
the Windows terminal command “DIR”
The output must be sorted, but printing extended details and producing multi-column output is not required.
Example output
For the list of paths:... | #Tcl | Tcl | puts [join [lsort [glob -nocomplain *]] "\n"] | Give a code snippet in #Tcl
Task
Write a program that will list everything in the current folder, similar to:
the Unix utility “ls” [1] or
the Windows terminal command “DIR”
The output must be sorted, but printing extended details and producing multi-column output is not required.
Example ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Price_fraction | Price fraction | A friend of mine runs a pharmacy. He has a specialized function in his Dispensary application which receives a decimal value of currency and replaces it to a standard value. This value is regulated by a government department.
Task
Given a floating point value between 0.00 and 1.00, rescale according to ... | #Delphi | Delphi |
class
APPLICATION
create
make
feature
make
--Tests the price_adjusted feature.
local
i: REAL
do
create price_fraction.initialize
from
i := 5
until
i = 100
loop
io.put_string ("Given: ")
io.put_real (i / 100)
io.put_string ("%TAdjusted:")
io.put_real (price_fracti... | Give a code snippet in #Delphi
A friend of mine runs a pharmacy. He has a specialized function in his Dispensary application which receives a decimal value of currency and replaces it to a standard value. This value is regulated by a government department.
Task
Given a floating point value between 0.00 and... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Walk_a_directory/Recursively | Walk a directory/Recursively | Task
Walk a given directory tree and print files matching a given pattern.
Note: This task is for recursive methods. These tasks should read an entire directory tree, not a single directory.
Note: Please be careful when running any code examples found here.
Related task
Walk a directory/Non-recursively ... | #E | E | def walkTree(directory, pattern) {
for name => file in directory {
if (name =~ rx`.*$pattern.*`) {
println(file.getPath())
}
if (file.isDirectory()) {
walkTree(file, pattern)
}
}
} | Give a code snippet in #E
Task
Walk a given directory tree and print files matching a given pattern.
Note: This task is for recursive methods. These tasks should read an entire directory tree, not a single directory.
Note: Please be careful when running any code examples found here.
Related task
Walk a d... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Jacobi_symbol | Jacobi symbol | The Jacobi symbol is a multiplicative function that generalizes the Legendre symbol. Specifically, the Jacobi symbol (a | n) equals the product of the Legendre symbols (a | p_i)^(k_i), where n = p_1^(k_1)*p_2^(k_2)*...*p_i^(k_i) and the Legendre symbol (a | p) denotes the value of a ^ ((p-1)/2) (mod p)
(a | p) ≡ 1 ... | #Raku | Raku | # Jacobi function
sub infix:<J> (Int $k is copy, Int $n is copy where * % 2) {
$k %= $n;
my $jacobi = 1;
while $k {
while $k %% 2 {
$k div= 2;
$jacobi *= -1 if $n % 8 == 3 | 5;
}
($k, $n) = $n, $k;
$jacobi *= -1 if 3 == $n%4 & $k%4;
$k %= $n;
... | Give a code snippet in #Raku
The Jacobi symbol is a multiplicative function that generalizes the Legendre symbol. Specifically, the Jacobi symbol (a | n) equals the product of the Legendre symbols (a | p_i)^(k_i), where n = p_1^(k_1)*p_2^(k_2)*...*p_i^(k_i) and the Legendre symbol (a | p) denotes the value of a ^ ((p-... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Aikido | Aikido |
foreach arg in args {
println ("arg: " + arg)
}
| Give a code snippet in #Aikido
Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| christopher/rosetta-code | |
http://rosettacode.org/wiki/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... | #C.23 | C# | using System;
using System.Linq;
internal class Program
{
private static void Main()
{
Console.WriteLine(String.Concat(Enumerable.Range('a', 26).Select(c => (char)c)));
}
} | Give a code snippet in #C.23
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/Generate_Chess960_starting_position | Generate Chess960 starting position | Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints:
as in the standard chess game, all eight white pawns must be placed on the second rank.
W... | #Tcl | Tcl | package require struct::list
proc chess960 {} {
while true {
set pos [join [struct::list shuffle {N N B B R R Q K}] ""]
if {[regexp {R.*K.*R} $pos] && [regexp {B(..)*B} $pos]} {
return $pos
}
}
}
# A simple renderer
proc chessRender {position} {
string map {P ♙ N ♘ B ♗ R ♖ Q ♕ K ♔} $position
}
... | Give a code snippet in #Tcl
Chess960 is a variant of chess created by world champion Bobby Fischer. Unlike other variants of the game, Chess960 does not require a different material, but instead relies on a random initial position, with a few constraints:
as in the standard chess game, all eight white pawns must be ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Parallel_calculations | Parallel calculations | Many programming languages allow you to specify computations to be run in parallel.
While Concurrent computing is focused on concurrency,
the purpose of this task is to distribute time-consuming calculations
on as many CPUs as possible.
Assume we have a collection of numbers, and want to find the one
with the largest ... | #PicoLisp | PicoLisp | (let Lst
(mapcan
'((N)
(later (cons) # When done,
(cons N (factor N)) ) ) # return the number and its factors
(quote
188573867500151328137405845301 # Process a collection of 12 numbers
3326500147448018653351160281
979950537738920439376739947... | Give a code snippet in #PicoLisp
Many programming languages allow you to specify computations to be run in parallel.
While Concurrent computing is focused on concurrency,
the purpose of this task is to distribute time-consuming calculations
on as many CPUs as possible.
Assume we have a collection of numbers, and want... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Pythagoras_tree | Pythagoras tree |
The Pythagoras tree is a fractal tree constructed from squares. It is named after Pythagoras because each triple of touching squares encloses a right triangle, in a configuration traditionally used to represent the Pythagorean theorem.
Task
Construct a Pythagoras tree of order 7 using only vectors (no rotation or ... | #Scala | Scala | import java.awt._
import java.awt.geom.Path2D
import javax.swing.{JFrame, JPanel, SwingUtilities, WindowConstants}
object PythagorasTree extends App {
SwingUtilities.invokeLater(() => {
new JFrame {
class PythagorasTree extends JPanel {
setPreferredSize(new Dimension(640, 640))
setBa... | Give a code snippet in #Scala
The Pythagoras tree is a fractal tree constructed from squares. It is named after Pythagoras because each triple of touching squares encloses a right triangle, in a configuration traditionally used to represent the Pythagorean theorem.
Task
Construct a Pythagoras tree of order 7 usin... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Averages/Simple_moving_average | Averages/Simple moving average | Computing the simple moving average of a series of numbers.
Task[edit]
Create a stateful function/class/instance that takes a period and returns a routine that takes a number as argument and returns a simple moving average of its arguments so far.
Description
A simple moving average is a method for computing an avera... | #Oforth | Oforth | import: parallel
: createSMA(period)
| ch |
Channel new [ ] over send drop ->ch
#[ ch receive + left(period) dup avg swap ch send drop ] ; | Give a code snippet in #Oforth
Computing the simple moving average of a series of numbers.
Task[edit]
Create a stateful function/class/instance that takes a period and returns a routine that takes a number as argument and returns a simple moving average of its arguments so far.
Description
A simple moving average is... | 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.
| #Action.21 | Action! | PROC PrintRight(BYTE num,size)
BYTE i
IF num<10 THEN
size==-1
ELSEIF num<100 THEN
size==-2
ELSE
size==-3
FI
FOR i=1 TO size
DO
Put(' )
OD
PrintB(num)
RETURN
PROC Main()
BYTE ARRAY colw=[1 1 1 2 2 2 2 2 2 3 3 3]
BYTE i,j,x,w
;clear screen
Put(125)
;draw frame
Positio... | Give a code snippet in #Action.21
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/Return_multiple_values | Return multiple values | Task
Show how to return more than one value from a function.
| #UNIX_Shell | UNIX Shell |
#!/bin/sh
funct1() {
a=$1
b=`expr $a + 1`
echo $a $b
}
values=`funct1 5`
set $values
x=$1
y=$2
echo "x=$x"
echo "y=$y"
| Give a code snippet in #UNIX_Shell
Task
Show how to return more than one value from a function.
| 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... | #Perl | Perl | my $sum = 0;
$sum += 1 / $_ ** 2 foreach 1..1000;
print "$sum\n"; | Give a code snippet in #Perl
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/Strip_control_codes_and_extended_characters_from_a_string | Strip control codes and extended characters from a string | Task
Strip control codes and extended characters from a string.
The solution should demonstrate how to achieve each of the following results:
a string with control codes stripped (but extended characters not stripped)
a string with control codes and extended characters stripped
In ASCII, the control codes ... | #AutoHotkey | AutoHotkey | Stripped(x){
Loop Parse, x
if Asc(A_LoopField) > 31 and Asc(A_LoopField) < 128
r .= A_LoopField
return r
}
MsgBox % stripped("`ba" Chr(00) "b`n`rc`fd" Chr(0xc3)) | Give a code snippet in #AutoHotkey
Task
Strip control codes and extended characters from a string.
The solution should demonstrate how to achieve each of the following results:
a string with control codes stripped (but extended characters not stripped)
a string with control codes and extended characters str... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Cullen_and_Woodall_numbers | Cullen and Woodall numbers | A Cullen number is a number of the form n × 2n + 1 where n is a natural number.
A Woodall number is very similar. It is a number of the form n × 2n - 1 where n is a natural number.
So for each n the associated Cullen number and Woodall number differ by 2.
Woodall numbers are sometimes referred to as Riesel numbers o... | #Verilog | Verilog | module main;
integer n, num;
initial begin
$display("First 20 Cullen numbers:");
for(n = 1; n <= 20; n=n+1)
begin
num = n * (2 ** n) + 1;
$write(num, " ");
end
$display("");
$display("First 20 Woodall numbers:");
for(n = 1; n <= 20; n=n+1)
begin
... | Give a code snippet in #Verilog
A Cullen number is a number of the form n × 2n + 1 where n is a natural number.
A Woodall number is very similar. It is a number of the form n × 2n - 1 where n is a natural number.
So for each n the associated Cullen number and Woodall number differ by 2.
Woodall numbers are sometime... | 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 ... | #SPL | SPL | fibo(n)=
s5 = #.sqrt(5)
<= (((1+s5)/2)^n-((1-s5)/2)^n)/s5
. | Give a code snippet in #SPL
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/Shortest_common_supersequence | Shortest common supersequence | The shortest common supersequence is a problem closely related to the longest common subsequence, which you can use as an external function for this task.
Task
Given two strings
u
{\displaystyle u}
and
v
{\displaystyle v}
, find the shortest possible sequence
s
{\displaystyle s}
, whic... | #Ada | Ada | with Ada.Text_IO;
procedure Shortest is
function Scs (Left, Right : in String) return String is
Left_Tail : String renames Left (Left'First + 1 .. Left'Last);
Right_Tail : String renames Right (Right'First + 1 .. Right'Last);
begin
if Left = "" then return Right; end if;
if Right =... | Give a code snippet in #Ada
The shortest common supersequence is a problem closely related to the longest common subsequence, which you can use as an external function for this task.
Task
Given two strings
u
{\displaystyle u}
and
v
{\displaystyle v}
, find the shortest possible sequence
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/Infinite | Loops/Infinite | Task
Print out SPAM followed by a newline in an infinite loop.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downward for
Loops/For
Loops/For with a specified step
Loops/Foreach
Loops/Increment loop index within l... | #Octave | Octave | while(1)
disp("SPAM")
endwhile | Give a code snippet in #Octave
Task
Print out SPAM followed by a newline in an infinite loop.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downward for
Loops/For
Loops/For with a specified step
Loops/Foreach
Loo... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Ultra_useful_primes | Ultra useful primes | An ultra-useful prime is a member of the sequence where each a(n) is the smallest positive integer k such that 2(2n) - k is prime.
k must always be an odd number since 2 to any power is always even.
Task
Find and show here, on this page, the first 10 elements of the sequence.
Stretch
Find and show the next sev... | #Wren | Wren | import "./big" for BigInt
import "./fmt" for Fmt
var one = BigInt.one
var two = BigInt.two
var a = Fn.new { |n|
var p = (BigInt.one << (1 << n)) - one
var k = 1
while (true) {
if (p.isProbablePrime(5)) return k
p = p - two
k = k + 2
}
}
System.print(" n k")
System.print("... | Give a code snippet in #Wren
An ultra-useful prime is a member of the sequence where each a(n) is the smallest positive integer k such that 2(2n) - k is prime.
k must always be an odd number since 2 to any power is always even.
Task
Find and show here, on this page, the first 10 elements of the sequence.
Stretc... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Chernick%27s_Carmichael_numbers | Chernick's Carmichael numbers | In 1939, Jack Chernick proved that, for n ≥ 3 and m ≥ 1:
U(n, m) = (6m + 1) * (12m + 1) * Product_{i=1..n-2} (2^i * 9m + 1)
is a Carmichael number if all the factors are primes and, for n > 4, m is a multiple of 2^(n-4).
Example
U(3, m) = (6m + 1) * (12m + 1) * (18m + 1)
U(4, m) = U(3, m) * (2^2 * 9m + 1)... | #Python | Python |
"""
Python implementation of
http://rosettacode.org/wiki/Chernick%27s_Carmichael_numbers
"""
# use sympy for prime test
from sympy import isprime
# based on C version
def primality_pretest(k):
if not (k % 3) or not (k % 5) or not (k % 7) or not (k % 11) or not(k % 13) or not (k % 17) or not (k % 19) o... | Give a code snippet in #Python
In 1939, Jack Chernick proved that, for n ≥ 3 and m ≥ 1:
U(n, m) = (6m + 1) * (12m + 1) * Product_{i=1..n-2} (2^i * 9m + 1)
is a Carmichael number if all the factors are primes and, for n > 4, m is a multiple of 2^(n-4).
Example
U(3, m) = (6m + 1) * (12m + 1) * (18m + 1)
U(... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Maze_generation | Maze generation |
This page uses content from Wikipedia. The original article was at Maze generation algorithm. 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
Generate and show a maze, using the simple Depth... | #MATLAB_.2F_Octave | MATLAB / Octave | function M = makeMaze(n)
showProgress = false;
colormap([1,1,1;1,1,1;0,0,0]);
set(gcf,'color','w');
NoWALL = 0;
WALL = 2;
NotVISITED = -1;
VISITED = -2;
m = 2*n+3;
M = NotVISITED(ones(m));
offsets = [-1, m, 1, -m];
M([1 2:2:end end],:) = WALL;
M(:... | Give a code snippet in #MATLAB_.2F_Octave
This page uses content from Wikipedia. The original article was at Maze generation algorithm. 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
Gener... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Increment_a_numerical_string | Increment a numerical string | Task
Increment a numerical string.
| #Go | Go | package main
import "fmt"
import "strconv"
func main() {
i, _ := strconv.Atoi("1234")
fmt.Println(strconv.Itoa(i + 1))
} | Give a code snippet in #Go
Task
Increment a numerical string.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Evolutionary_algorithm | Evolutionary algorithm | Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closeness’ of its argument to the target string.... | #Icon_and_Unicon | Icon and Unicon | global target, chars, parent, C, M, current_fitness
procedure fitness(s)
fit := 0
#Increment the fitness for every position in the string s that matches the target
every i := 1 to *target & s[i] == target[i] do fit +:= 1
return fit
end
procedure mutate(s)
#If a random number between 0 and 1 is inside the bound... | Give a code snippet in #Icon_and_Unicon
Starting with:
The target string: "METHINKS IT IS LIKE A WEASEL".
An array of random characters chosen from the set of upper-case letters together with the space, and of the same length as the target string. (Call it the parent).
A fitness function that computes the ‘closene... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Create_a_file | Create a file | In this task, the job is to create a new empty file called "output.txt" of size 0 bytes
and an empty directory called "docs". This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root.
| #Clojure | Clojure | (import '(java.io File))
(.createNewFile (new File "output.txt"))
(.mkdir (new File "docs"))
(.createNewFile (File. (str (File/separator) "output.txt")))
(.mkdir (File. (str (File/separator) "docs"))) | Give a code snippet in #Clojure
In this task, the job is to create a new empty file called "output.txt" of size 0 bytes
and an empty directory called "docs". This should be done twice: once "here", i.e. in the current working directory and once in the filesystem root.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Write_float_arrays_to_a_text_file | Write float arrays to a text file | Task
Write two equal-sized numerical arrays 'x' and 'y' to
a two-column text file named 'filename'.
The first column of the file contains values from an 'x'-array with a
given 'xprecision', the second -- values from 'y'-array with 'yprecision'.
For example, considering:
x = {1, 2, 3, 1e11};
y = {1, 1.41421356... | #COBOL | COBOL |
identification division.
program-id. wr-float.
environment division.
input-output section.
file-control.
select report-file assign "float.txt"
organization sequential.
data division.
file section.
fd report-file
report is flo... | Give a code snippet in #COBOL
Task
Write two equal-sized numerical arrays 'x' and 'y' to
a two-column text file named 'filename'.
The first column of the file contains values from an 'x'-array with a
given 'xprecision', the second -- values from 'y'-array with 'yprecision'.
For example, considering:
x = {1, 2, ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Empty_program | Empty program | Task
Create the simplest possible program that is still considered "correct."
| #Pascal | Pascal | program ProgramName;
begin
end. | Give a code snippet in #Pascal
Task
Create the simplest possible program that is still considered "correct."
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Equilibrium_index | Equilibrium index | An equilibrium index of a sequence is an index into the sequence such that the sum of elements at lower indices is equal to the sum of elements at higher indices.
For example, in a sequence
A
{\displaystyle A}
:
A
0
=
−
7
{\displaystyle A_{0}=-7}
A
1
=
1
{\displaystyle A_{1}=1}
... | #Racket | Racket |
#lang racket
(define (subsums xs)
(for/fold ([sums '()] [sum 0]) ([x xs])
(values (cons (+ x sum) sums)
(+ x sum))))
(define (equivilibrium xs)
(define-values (sums total) (subsums xs))
(for/list ([sum (reverse sums)]
[x xs]
[i (in-naturals)]
#:when (= (-... | Give a code snippet in #Racket
An equilibrium index of a sequence is an index into the sequence such that the sum of elements at lower indices is equal to the sum of elements at higher indices.
For example, in a sequence
A
{\displaystyle A}
:
A
0
=
−
7
{\displaystyle A_{0}=-7}
A
1
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Euler%27s_identity | Euler's identity |
This page uses content from Wikipedia. The original article was at Euler's_identity. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
In mathematics, Euler's identity is the equality:
... | #FreeBASIC | FreeBASIC | #define PI 3.141592653589793238462643383279502884197169399375105821
#define MAXITER 12
'---------------------------------------
' complex numbers and their arithmetic
'---------------------------------------
type complex
r as double
i as double
end type
function conj( a as complex ) as complex
dim a... | Give a code snippet in #FreeBASIC
This page uses content from Wikipedia. The original article was at Euler's_identity. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
In mathematics, Euler's ident... | christopher/rosetta-code | |
http://rosettacode.org/wiki/String_interpolation_(included) | String interpolation (included) |
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 |... | #TUSCRIPT | TUSCRIPT |
$$ MODE TUSCRIPT
sentence_old="Mary had a X lamb."
values=*
DATA little
DATA big
sentence_new=SUBSTITUTE (sentence_old,":X:",0,0,values)
PRINT sentence_old
PRINT sentence_new
| Give a code snippet in #TUSCRIPT
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/Earliest_difference_between_prime_gaps | Earliest difference between prime gaps | When calculating prime numbers > 2, the difference between adjacent primes is always an even number. This difference, also referred to as the gap, varies in an random pattern; at least, no pattern has ever been discovered, and it is strongly conjectured that no pattern exists. However, it is also conjectured that betwe... | #Sidef | Sidef | func prime_gap_records(upto) {
var gaps = []
var p = 3
each_prime(p.next_prime, upto, {|q|
gaps[q-p] := p
p = q
})
gaps.grep { defined(_) }
}
var gaps = prime_gap_records(1e8)
for m in (1 .. gaps.max.len) {
gaps.each_cons(2, {|p,q|
if (abs(q-p) > 10**m) {
... | Give a code snippet in #Sidef
When calculating prime numbers > 2, the difference between adjacent primes is always an even number. This difference, also referred to as the gap, varies in an random pattern; at least, no pattern has ever been discovered, and it is strongly conjectured that no pattern exists. However, it... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Factors_of_an_integer | Factors of an 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 |... | #Wortel | Wortel | @let {
factors1 &n !-\%%n @to n
factors_tacit @(\\%% !- @to)
[[
!factors1 10
!factors_tacit 100
!factors1 720
]]
} | Give a code snippet in #Wortel
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... | 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.
... | #IDL | IDL | f = file_search('*.txt', count=cc)
if cc gt 0 then print,f | Give a code snippet in #IDL
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, no... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Composite_numbers_k_with_no_single_digit_factors_whose_factors_are_all_substrings_of_k | Composite numbers k with no single digit factors whose factors are all substrings of k | Find the composite numbers k in base 10, that have no single digit prime factors and whose prime factors are all a substring of k.
Task
Find and show here, on this page, the first ten elements of the sequence.
Stretch
Find and show the next ten elements.
| #ALGOL_68 | ALGOL 68 | BEGIN # find composite k with no single digit factors whose factors are all substrings of k #
# returns TRUE if the string representation of f is a substring of k str, FALSE otherwise #
PROC is substring = ( STRING k str, INT f )BOOL:
BEGIN
STRING f str = whole( f, 0 );
INT ... | Give a code snippet in #ALGOL_68
Find the composite numbers k in base 10, that have no single digit prime factors and whose prime factors are all a substring of k.
Task
Find and show here, on this page, the first ten elements of the sequence.
Stretch
Find and show the next ten elements.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/FizzBuzz | FizzBuzz | Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
... | #CSS | CSS | <!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
<head>
<style>
li {
list-style-position: inside;
}
li:nth-child(3n), li:nth-child(5n) {
list-style-type: none;
}
li:nth-child(3n)::before {
content:'Fizz';
}
li:nth-child(5n)::after {
content:'Buzz';
}
</style>
</head>
<body>
<ol>
<li><... | Give a code snippet in #CSS
Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/User_input/Text | User input/Text | User input/Text is part of Short Circuit's Console Program Basics selection.
Task
Input a string and the integer 75000 from the text console.
See also: User input/Graphical
| #Nemerle | Nemerle | using System;
using System.Console;
module Input
{
Main() : void
{
Write("Enter a string:");
_ = ReadLine()
mutable entry = 0;
mutable numeric = false;
do
{
Write("Enter 75000:");
numeric = int.TryParse(ReadLine(), out entry);
... | Give a code snippet in #Nemerle
User input/Text is part of Short Circuit's Console Program Basics selection.
Task
Input a string and the integer 75000 from the text console.
See also: User input/Graphical
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Strip_a_set_of_characters_from_a_string | Strip a set of characters from a string | Task
Create a function that strips a set of characters from a string.
The function should take two arguments:
a string to be stripped
a string containing the set of characters to be stripped
The returned string should contain the first string, stripped of any characters in the second argument:
print str... | #Maple | Maple | with(StringTools):
Remove(c->Has("aei",c), "She was a soul stripper. She took my heart!"); | Give a code snippet in #Maple
Task
Create a function that strips a set of characters from a string.
The function should take two arguments:
a string to be stripped
a string containing the set of characters to be stripped
The returned string should contain the first string, stripped of any characters in t... | christopher/rosetta-code | |
http://rosettacode.org/wiki/String_case | String case | Task
Take the string alphaBETA and demonstrate how to convert it to:
upper-case and
lower-case
Use the default encoding of a string literal or plain ASCII if there is no string literal in your language.
Note: In some languages alphabets toLower and toUpper is not reversable.
Show any additional... | #AppleScript | AppleScript | use framework "Foundation"
-- TEST -----------------------------------------------------------------------
on run
ap({toLower, toTitle, toUpper}, {"alphaBETA αβγδΕΖΗΘ"})
--> {"alphabeta αβγδεζηθ", "Alphabeta Αβγδεζηθ", "ALPHABETA ΑΒΓΔΕΖΗΘ"}
end run
-- GENERIC FUNCTIONS ------------------------------... | Give a code snippet in #AppleScript
Task
Take the string alphaBETA and demonstrate how to convert it to:
upper-case and
lower-case
Use the default encoding of a string literal or plain ASCII if there is no string literal in your language.
Note: In some languages alphabets toLower and toUpper is... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Runtime_evaluation/In_an_environment | Runtime evaluation/In an environment | x
x
x
Do so in a way which:
does not involve string manipulation of the input source code
is plausibly extensible to a runtime-chosen set of bindings rather than just x
does not make x a global variable
or note that these are impossible.
See also
For more general examples and language-specific details, see... | #Phix | Phix | without javascript_semantics
requires("1.0.1")
include eval.e
function eval_with_x(string expr, integer a, b)
return eval(expr,{"x"},{{"x",b}})[1] -
eval(expr,{"x"},{{"x",a}})[1]
end function
?eval_with_x("integer x = power(2,x)",3,5)
| Give a code snippet in #Phix
x
x
x
Do so in a way which:
does not involve string manipulation of the input source code
is plausibly extensible to a runtime-chosen set of bindings rather than just x
does not make x a global variable
or note that these are impossible.
See also
For more general examples and ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sorting_algorithms/Selection_sort | Sorting algorithms/Selection 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
... | #Java | Java | public static void sort(int[] nums){
for(int currentPlace = 0;currentPlace<nums.length-1;currentPlace++){
int smallest = Integer.MAX_VALUE;
int smallestAt = currentPlace+1;
for(int check = currentPlace; check<nums.length;check++){
if(nums[check]<smallest){
smallestAt = check;
smallest = nums[check];
... | Give a code snippet in #Java
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/Square_but_not_cube | Square but not cube | Task
Show the first 30 positive integers which are squares but not cubes of such integers.
Optionally, show also the first 3 positive integers which are both squares and cubes, and mark them as such.
| #Nim | Nim | var count = 0
var n, c, c3 = 1
while count < 30:
var sq = n * n
while c3 < sq:
inc c
c3 = c * c * c
if c3 == sq:
echo sq, " is square and cube"
else:
echo sq
inc count
inc n | Give a code snippet in #Nim
Task
Show the first 30 positive integers which are squares but not cubes of such integers.
Optionally, show also the first 3 positive integers which are both squares and cubes, and mark them as such.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/Infinite | Loops/Infinite | Task
Print out SPAM followed by a newline in an infinite loop.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downward for
Loops/For
Loops/For with a specified step
Loops/Foreach
Loops/Increment loop index within l... | #Wart | Wart | repeat :forever
prn "spam" | Give a code snippet in #Wart
Task
Print out SPAM followed by a newline in an infinite loop.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downward for
Loops/For
Loops/For with a specified step
Loops/Foreach
Loops... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Continued_fraction/Arithmetic/Construct_from_rational_number | Continued fraction/Arithmetic/Construct from rational number | Continued fraction arithmetic
The purpose of this task is to write a function
r
2
c
f
(
i
n
t
{\displaystyle {\mathit {r2cf}}(\mathrm {int} }
N
1
,
i
n
t
{\displaystyle N_{1},\mathrm {int} }
N
2
)
{\displaystyle N_{2})}
, or
r
2
c
f
(
F
r
a
c
t
i
o
n
{\displaystyle {\m... | #Scheme | Scheme | ; Create a terminating Continued Fraction generator for the given rational number.
; Returns one term per call; returns #f when no more terms remaining.
(define make-continued-fraction-gen
(lambda (rat)
(let ((num (numerator rat)) (den (denominator rat)))
(lambda ()
(if (= den 0)
#f
... | Give a code snippet in #Scheme
Continued fraction arithmetic
The purpose of this task is to write a function
r
2
c
f
(
i
n
t
{\displaystyle {\mathit {r2cf}}(\mathrm {int} }
N
1
,
i
n
t
{\displaystyle N_{1},\mathrm {int} }
N
2
)
{\displaystyle N_{2})}
, or
r
2
c
f
(
F
r
a... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Quine | Quine | A quine is a self-referential program that can,
without any external access, output its own source.
A quine (named after Willard Van Orman Quine) is also known as:
self-reproducing automata (1972)
self-replicating program or self-replicating computer program
self-reproducing program ... | #Shale | Shale | i var i "i var i %c%s%c = 34 i 34 i printf" = 34 i 34 i printf | Give a code snippet in #Shale
A quine is a self-referential program that can,
without any external access, output its own source.
A quine (named after Willard Van Orman Quine) is also known as:
self-reproducing automata (1972)
self-replicating program or self-replicating computer program
... | 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.
| #PicoLisp | PicoLisp |
# The Rectangle class
(class +Rectangle +Shape)
# dx dy
(dm T (X Y DX DY)
(super X Y)
(=: dx DX)
(=: dy DY) )
(dm area> ()
(* (: dx) (: dy)) )
(dm perimeter> ()
(* 2 (+ (: dx) (: dy))) )
(dm draw> ()
(drawRect (: x) (: y) (: dx) (: dy)) ) # Hypothetical function 'drawRect'
| Give a code snippet in #PicoLisp
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/Algebraic_data_types | Algebraic data types | Some languages offer direct support for algebraic data types and pattern matching on them. While this of course can always be simulated with manual tagging and conditionals, it allows for terse code which is easy to read, and can represent the algorithm directly.
Task
As an example, implement insertion in a red-bla... | #OCaml | OCaml |
type color = R | B
type 'a tree = E | T of color * 'a tree * 'a * 'a tree
(** val balance : color * 'a tree * 'a * 'a tree -> 'a tree *)
let balance = function
| B, T (R, T (R,a,x,b), y, c), z, d
| B, T (R, a, x, T (R,b,y,c)), z, d
| B, a, x, T (R, T (R,b,y,c), z, d)
| B, a, x, T (R, b, y, T (R,c,z,d)) -> T... | Give a code snippet in #OCaml
Some languages offer direct support for algebraic data types and pattern matching on them. While this of course can always be simulated with manual tagging and conditionals, it allows for terse code which is easy to read, and can represent the algorithm directly.
Task
As an example, i... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Forward_difference | Forward difference | Task
Provide code that produces a list of numbers which is the nth order forward difference, given a non-negative integer (specifying the order) and a list of numbers.
The first-order forward difference of a list of numbers A is a new list B, where Bn = An+1 - An.
List B should have one fewer elem... | #Ruby | Ruby | def dif(s)
s.each_cons(2).collect { |x, y| y - x }
end
def difn(s, n)
n.times.inject(s) { |s, | dif(s) }
end | Give a code snippet in #Ruby
Task
Provide code that produces a list of numbers which is the nth order forward difference, given a non-negative integer (specifying the order) and a list of numbers.
The first-order forward difference of a list of numbers A is a new list B, where Bn = An+1 - An.
List ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Abundant_odd_numbers | Abundant odd numbers | An Abundant number is a number n for which the sum of divisors σ(n) > 2n,
or, equivalently, the sum of proper divisors (or aliquot sum) s(n) > n.
E.G.
12 is abundant, it has the proper divisors 1,2,3,4 & 6 which sum to 16 ( > 12 or n);
or alternately, has the sigma sum of ... | #J | J | NB. https://www.math.upenn.edu/~deturck/m170/wk3/lecture/sumdiv.html
s=: ([: */ [: ((<:@:(^ >:)/) % <:@:{.) __&q:)&>
assert 6045 -: s 1800
aliquot_sum=: -~ s
abundant=: < aliquot_sum
Filter=: (#~`)(`:6)
A=: abundant Filter 1 2 p. i. 260000 NB. a batch of abundant odd numbers
# A NB. mor... | Give a code snippet in #J
An Abundant number is a number n for which the sum of divisors σ(n) > 2n,
or, equivalently, the sum of proper divisors (or aliquot sum) s(n) > n.
E.G.
12 is abundant, it has the proper divisors 1,2,3,4 & 6 which sum to 16 ( > 12 or n);
or alternate... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/Break | Loops/Break | Task
Show a loop which prints random numbers (each number newly generated each loop) from 0 to 19 (inclusive).
If a number is 10, stop the loop after printing it, and do not generate any further numbers.
Otherwise, generate and print a second random number before restarting the loop.
If the number 10 is never gener... | #Haxe | Haxe | class Program {
static public function main():Void {
while(true) {
var a = Std.random(20);
Sys.println(a);
if (a == 10)
break;
var b = Std.random(20);
Sys.println(b);
}
}
} | Give a code snippet in #Haxe
Task
Show a loop which prints random numbers (each number newly generated each loop) from 0 to 19 (inclusive).
If a number is 10, stop the loop after printing it, and do not generate any further numbers.
Otherwise, generate and print a second random number before restarting the loop.
I... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Apply_a_callback_to_an_array | Apply a callback to an array | Task
Take a combined set of elements and apply a function to each element.
| #VBScript | VBScript |
class callback
dim sRule
public property let rule( x )
sRule = x
end property
public default function applyTo(a)
dim p1
for i = lbound( a ) to ubound( a )
p1 = a( i )
a( i ) = eval( sRule )
next
applyTo = a
end function
end class
| Give a code snippet in #VBScript
Task
Take a combined set of elements and apply a function to each element.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Fractran | Fractran | FRACTRAN is a Turing-complete esoteric programming language invented by the mathematician John Horton Conway.
A FRACTRAN program is an ordered list of positive fractions
P
=
(
f
1
,
f
2
,
…
,
f
m
)
{\displaystyle P=(f_{1},f_{2},\ldots ,f_{m})}
, together with an initial positive integer input
n
... | #bash | bash | #! /bin/bash
program="1/1 455/33 11/13 1/11 3/7 11/2 1/3"
echo $program | tr " " "\n" | cut -d"/" -f1 | tr "\n" " " > "data"
read -a ns < "data"
echo $program | tr " " "\n" | cut -d"/" -f2 | tr "\n" " " > "data"
read -a ds < "data"
t=0
n=72
echo "steps of computation" > steps.csv
while [ $t -le 6 ]; do
if [ $(($n*... | Give a code snippet in #bash
FRACTRAN is a Turing-complete esoteric programming language invented by the mathematician John Horton Conway.
A FRACTRAN program is an ordered list of positive fractions
P
=
(
f
1
,
f
2
,
…
,
f
m
)
{\displaystyle P=(f_{1},f_{2},\ldots ,f_{m})}
, together with an initial... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Execute_a_system_command | Execute a system command | Task
Run either the ls system command (dir on Windows), or the pause system command.
Related task
Get system command output
| #Erlang | Erlang | os:cmd("ls"). | Give a code snippet in #Erlang
Task
Run either the ls system command (dir on Windows), or the pause system command.
Related task
Get system command output
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Bulls_and_cows | Bulls and cows | Bulls and Cows
Task
Create a four digit random number from the digits 1 to 9, without duplication.
The program should:
ask for guesses to this number
reject guesses that are malformed
print the score for the guess
The score is computed as:
The player wins if the guess is the same as the random... | #FreeBASIC | FreeBASIC | function get_digit( num as uinteger, ps as uinteger ) as uinteger
return (num mod 10^(ps+1))\10^ps
end function
function is_malformed( num as uinteger ) as boolean
if num > 9876 then return true
dim as uinteger i, j
for i = 0 to 2
for j = i+1 to 3
if get_digit( num, j ) = get_digit... | Give a code snippet in #FreeBASIC
Bulls and Cows
Task
Create a four digit random number from the digits 1 to 9, without duplication.
The program should:
ask for guesses to this number
reject guesses that are malformed
print the score for the guess
The score is computed as:
The player wins if ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Cantor_set | Cantor set | Task
Draw a Cantor set.
See details at this Wikipedia webpage: Cantor set
| #Modula-2 | Modula-2 | MODULE Cantor;
FROM Terminal IMPORT Write,WriteLn,ReadChar;
CONST
WIDTH = 81;
HEIGHT = 5;
VAR
lines : ARRAY[0..HEIGHT] OF ARRAY[0..WIDTH] OF CHAR;
PROCEDURE Init;
VAR i,j : CARDINAL;
BEGIN
FOR i:=0 TO HEIGHT DO
FOR j:=0 TO WIDTH DO
lines[i,j] := '*'
END
END
END Init;
... | Give a code snippet in #Modula-2
Task
Draw a Cantor set.
See details at this Wikipedia webpage: Cantor set
| 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... | #Phix | Phix | seed(x) = mod(950706376 * seed(x-1), 2147483647)
random(x) = seed(x) / 2147483647 | Give a code snippet in #Phix
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... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Perfect_shuffle | Perfect shuffle | A perfect shuffle (or faro/weave shuffle) means splitting a deck of cards into equal halves, and perfectly interleaving them - so that you end up with the first card from the left half, followed by the first card from the right half, and so on:
7♠ 8♠ 9♠ J♠ Q♠ K♠→7♠ 8♠ 9♠
J♠ Q♠ K♠→7♠ J♠ 8♠ Q♠ 9♠ K♠
When you ... | #Delphi | Delphi |
program Perfect_shuffle;
{$APPTYPE CONSOLE}
uses
System.SysUtils;
type
TDeck = record
Cards: TArray<Integer>;
Len: Integer;
constructor Create(deckSize: Integer); overload;
constructor Create(deck: TDeck); overload;
procedure shuffleDeck();
class operator Equal(a, b: TDeck): boolean;... | Give a code snippet in #Delphi
A perfect shuffle (or faro/weave shuffle) means splitting a deck of cards into equal halves, and perfectly interleaving them - so that you end up with the first card from the left half, followed by the first card from the right half, and so on:
7♠ 8♠ 9♠ J♠ Q♠ K♠→7♠ 8♠ 9♠
J♠ Q♠ ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/Infinite | Loops/Infinite | Task
Print out SPAM followed by a newline in an infinite loop.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downward for
Loops/For
Loops/For with a specified step
Loops/Foreach
Loops/Increment loop index within l... | #Python | Python | while 1:
print "SPAM" | Give a code snippet in #Python
Task
Print out SPAM followed by a newline in an infinite loop.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downward for
Loops/For
Loops/For with a specified step
Loops/Foreach
Loo... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Balanced_brackets | Balanced brackets | Task:
Generate a string with N opening brackets [ and with N closing brackets ], in some arbitrary order.
Determine whether the generated string is balanced; that is, whether it consists entirely of pairs of opening/closing brackets (in that order), none of which mis-nest.
Examples
(empty) ... | #Ruby | Ruby | re = /\A # beginning of string
(?<bb> # begin capture group <bb>
\[ # literal [
\g<bb>* # zero or more <bb>
\] # literal ]
)* # end group, zero or more such groups
\z/x # end of string
10.times do |i|
s = (%w{[ ]} * i).shuffle.join
puts (s =~ re ? " OK: "... | Give a code snippet in #Ruby
Task:
Generate a string with N opening brackets [ and with N closing brackets ], in some arbitrary order.
Determine whether the generated string is balanced; that is, whether it consists entirely of pairs of opening/closing brackets (in that order), none of which mis-ne... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Fibonacci_word | Fibonacci word | The Fibonacci Word may be created in a manner analogous to the Fibonacci Sequence as described here:
Define F_Word1 as 1
Define F_Word2 as 0
Form F_Word3 as F_Word2 concatenated with F_Word1 i.e.: 01
Form F_Wordn as F_Wordn-1 concatenated with F_wordn-... | #F.C5.8Drmul.C3.A6 | Fōrmulæ | package main
import (
"fmt"
"math"
)
// From http://rosettacode.org/wiki/Entropy#Go
func entropy(s string) float64 {
m := map[rune]float64{}
for _, r := range s {
m[r]++
}
hm := 0.
for _, c := range m {
hm += c * math.Log2(c)
}
l := float64(len(s))
return math.Log2(l) - hm/l
}
const F_Word1 = "1"
co... | Give a code snippet in #F.C5.8Drmul.C3.A6
The Fibonacci Word may be created in a manner analogous to the Fibonacci Sequence as described here:
Define F_Word1 as 1
Define F_Word2 as 0
Form F_Word3 as F_Word2 concatenated with F_Word1 i.e.: 01
Form F_Wordn as... | christopher/rosetta-code | |
http://rosettacode.org/wiki/100_doors | 100 doors | There are 100 doors in a row that are all initially closed.
You make 100 passes by the doors.
The first time through, visit every door and toggle the door (if the door is closed, open it; if it is open, close it).
The second time, only visit every 2nd door (door #2, #4, #6, ...), and toggle it.
The third... | #Forth | Forth | : toggle ( c-addr -- ) \ toggle the byte at c-addr
dup c@ 1 xor swap c! ;
100 1+ ( 1-based indexing ) constant ndoors
create doors ndoors allot
: init ( -- ) doors ndoors erase ; \ close all doors
: pass ( n -- ) \ toggle every nth door
ndoors over do
doors i + toggle
dup ( n ) +loop dro... | Give a code snippet in #Forth
There are 100 doors in a row that are all initially closed.
You make 100 passes by the doors.
The first time through, visit every door and toggle the door (if the door is closed, open it; if it is open, close it).
The second time, only visit every 2nd door (door #2, #4, #6, ..... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sorting_algorithms/Cocktail_sort | Sorting algorithms/Cocktail 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
... | #Lua | Lua | function cocktailSort( A )
local swapped
repeat
swapped = false
for i = 1, #A - 1 do
if A[ i ] > A[ i+1 ] then
A[ i ], A[ i+1 ] = A[ i+1 ] ,A[i]
swapped=true
end
end
if swapped == false then
break -- repeatd loop;
end
for i = #A - 1,1,-1 do
if A[ i ] >... | Give a code snippet in #Lua
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Hello_world/Text | Hello world/Text | Hello world/Text is part of Short Circuit's Console Program Basics selection.
Task
Display the string Hello world! on a text console.
Related tasks
Hello world/Graphical
Hello world/Line Printer
Hello world/Newbie
Hello world/Newline omission
Hello world/Standard error
Hello world/Web server
| #Lean | Lean |
#eval "Hello world!"
| Give a code snippet in #Lean
Hello world/Text is part of Short Circuit's Console Program Basics selection.
Task
Display the string Hello world! on a text console.
Related tasks
Hello world/Graphical
Hello world/Line Printer
Hello world/Newbie
Hello world/Newline omission
Hello world/Standard error
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Multi-dimensional_array | Multi-dimensional array | For the purposes of this task, the actual memory layout or access method of this data structure is not mandated.
It is enough to:
State the number and extent of each index to the array.
Provide specific, ordered, integer indices for all dimensions of the array together with a new value to update the indexed value.
... | #REXX | REXX | g = antenna.2.0 | Give a code snippet in #REXX
For the purposes of this task, the actual memory layout or access method of this data structure is not mandated.
It is enough to:
State the number and extent of each index to the array.
Provide specific, ordered, integer indices for all dimensions of the array together with a new value... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Null_object | Null object |
Null (or nil) is the computer science concept of an undefined or unbound object.
Some languages have an explicit way to access the null object, and some don't.
Some languages distinguish the null object from undefined values, and some don't.
Task
Show how to access null in your language by checking to see if an ob... | #Wart | Wart | (not nil)
| Give a code snippet in #Wart
Null (or nil) is the computer science concept of an undefined or unbound object.
Some languages have an explicit way to access the null object, and some don't.
Some languages distinguish the null object from undefined values, and some don't.
Task
Show how to access null in your langua... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Strip_whitespace_from_a_string/Top_and_tail | Strip whitespace from a string/Top and tail | Task
Demonstrate how to strip leading and trailing whitespace from a string.
The solution should demonstrate how to achieve the following three results:
String with leading whitespace removed
String with trailing whitespace removed
String with both leading and trailing whitespace removed
For the purposes of thi... | #M2000_Interpreter | M2000 Interpreter |
Module CheckIt {
filter$=chr$(0)
for i=1 to 31:filter$+=chr$(i):next
a$=chr$(9)+" There are unwanted blanks here! "+chr$(9)
a$=filter$(a$,filter$) ' exclude non printable characters
\\ string encoded as UTF16LE
Print Len(a$)=39
Print(ltrim$(a$))
Print(rtrim$(a$))
Print(trim$(a$))
\\ string encoded a... | Give a code snippet in #M2000_Interpreter
Task
Demonstrate how to strip leading and trailing whitespace from a string.
The solution should demonstrate how to achieve the following three results:
String with leading whitespace removed
String with trailing whitespace removed
String with both leading and trailing w... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Binary_search | Binary search | A binary search divides a range of values into halves, and continues to narrow down the field of search until the unknown value is found. It is the classic example of a "divide and conquer" algorithm.
As an analogy, consider the children's game "guess a number." The scorer has a secret number, and will only tell the p... | #Brat | Brat | binary_search = { search_array, value, low, high |
true? high < low
{ null }
{
mid = ((low + high) / 2).to_i
true? search_array[mid] > value
{ binary_search search_array, value, low, mid - 1 }
{ true? search_array[mid] < value
{ binary_search search_array, value, mid + 1, high }
{... | Give a code snippet in #Brat
A binary search divides a range of values into halves, and continues to narrow down the field of search until the unknown value is found. It is the classic example of a "divide and conquer" algorithm.
As an analogy, consider the children's game "guess a number." The scorer has a secret nu... | 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
)
)
,
... | #uBasic.2F4tH | uBasic/4tH | LOCAL(1) ' main uses locals as well
FOR a@ = 0 TO 200 ' set the array
@(a@) = -1
NEXT
PRINT "F sequence:" ' print the F-sequence
FOR a@ = 0 TO 20
PRINT FUNC(_f(a@));" ";
NEXT
PRINT
PRINT "M sequence:" ' print the M-sequen... | Give a code snippet in #uBasic.2F4tH
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
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Attractive_numbers | Attractive numbers | A number is an attractive number if the number of its prime factors (whether distinct or not) is also prime.
Example
The number 20, whose prime decomposition is 2 × 2 × 5, is an attractive number because the number of its prime factors (3) is also prime.
Task
Show sequence items up to 120.... | #COBOL | COBOL | IDENTIFICATION DIVISION.
PROGRAM-ID. ATTRACTIVE-NUMBERS.
DATA DIVISION.
WORKING-STORAGE SECTION.
77 MAXIMUM PIC 999 VALUE 120.
01 SIEVE-DATA VALUE SPACES.
03 MARKER PIC X OCCURS 120 TIMES.
88 PRIME VALUE SPACE.
03 SIEVE-... | Give a code snippet in #COBOL
A number is an attractive number if the number of its prime factors (whether distinct or not) is also prime.
Example
The number 20, whose prime decomposition is 2 × 2 × 5, is an attractive number because the number of its prime factors (3) is also prime.
Task
S... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Maze_solving | Maze solving | Task
For a maze generated by this task, write a function
that finds (and displays) the shortest path between two cells.
Note that because these mazes are generated by the Depth-first search algorithm, they contain no circular paths,
and a simple depth-first tree search can be used.
| #Wren | Wren | import "os" for Process
import "/ioutil" for File, FileUtil
/*
* Makes the maze half as wide (i. e. "+---+" becomes "+-+"), so that
* each cell in the maze is the same size horizontally as vertically.
* (Versus the expanded version, which looks better visually.)
* Also, converts each line of the maze ... | Give a code snippet in #Wren
Task
For a maze generated by this task, write a function
that finds (and displays) the shortest path between two cells.
Note that because these mazes are generated by the Depth-first search algorithm, they contain no circular paths,
and a simple depth-first tree search can be used.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Phix | Phix | with javascript_semantics
constant cmd = command_line()
?cmd
if cmd[1]=cmd[2] then
printf(1,"Compiled executable name: %s\n",{cmd[1]})
else
printf(1,"Interpreted (using %s) source name: %s\n",cmd[1..2])
end if
if length(cmd)>2 then
puts(1,"Command line arguments:\n")
for i = 3 to length(cmd) do
printf(1... | Give a code snippet in #Phix
Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Forward_difference | Forward difference | Task
Provide code that produces a list of numbers which is the nth order forward difference, given a non-negative integer (specifying the order) and a list of numbers.
The first-order forward difference of a list of numbers A is a new list B, where Bn = An+1 - An.
List B should have one fewer elem... | #Nim | Nim | proc dif(s: seq[int]): seq[int] =
result = newSeq[int](s.len-1)
for i in 0..<s.high:
result[i] = s[i+1] - s[i]
proc difn(s: seq[int]; n: int): seq[int] =
if n > 0: difn(dif(s), n-1)
else: s
const s = @[90, 47, 58, 29, 22, 32, 55, 5, 55, 73]
echo difn(s, 0)
echo difn(s, 1)
echo difn(s, 2) | Give a code snippet in #Nim
Task
Provide code that produces a list of numbers which is the nth order forward difference, given a non-negative integer (specifying the order) and a list of numbers.
The first-order forward difference of a list of numbers A is a new list B, where Bn = An+1 - An.
List B... | 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.
| #TUSCRIPT | TUSCRIPT |
$$ MODE TUSCRIPT
- delete file
SET status = DELETE ("input.txt")
- delete directory
SET status = DELETE ("docs",-std-)
| Give a code snippet in #TUSCRIPT
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/Knapsack_problem/0-1 | Knapsack problem/0-1 | A tourist wants to make a good trip at the weekend with his friends.
They will go to the mountains to see the wonders of nature, so he needs to pack well for the trip.
He has a good knapsack for carrying things, but knows that he can carry a maximum of only 4kg in it, and it will have to last the whole day.
He cre... | #Elixir | Elixir | defmodule Knapsack do
def solve([], _total_weight, item_acc, value_acc, weight_acc), do:
{item_acc, value_acc, weight_acc}
def solve([{_item, item_weight, _item_value} | t],
total_weight,
item_acc,
value_acc,
weight_acc) when item_weight > total_weight, do:
so... | Give a code snippet in #Elixir
A tourist wants to make a good trip at the weekend with his friends.
They will go to the mountains to see the wonders of nature, so he needs to pack well for the trip.
He has a good knapsack for carrying things, but knows that he can carry a maximum of only 4kg in it, and it will hav... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Repeat_a_string | Repeat a string | Take a string and repeat it some number of times.
Example: repeat("ha", 5) => "hahahahaha"
If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("*", 5) => "*****").
Other tasks re... | #Crystal | Crystal |
puts "ha" * 5
| Give a code snippet in #Crystal
Take a string and repeat it some number of times.
Example: repeat("ha", 5) => "hahahahaha"
If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("*", 5... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Null_object | Null object |
Null (or nil) is the computer science concept of an undefined or unbound object.
Some languages have an explicit way to access the null object, and some don't.
Some languages distinguish the null object from undefined values, and some don't.
Task
Show how to access null in your language by checking to see if an ob... | #PowerShell | PowerShell | if ($null -eq $object) {
...
} | Give a code snippet in #PowerShell
Null (or nil) is the computer science concept of an undefined or unbound object.
Some languages have an explicit way to access the null object, and some don't.
Some languages distinguish the null object from undefined values, and some don't.
Task
Show how to access null in your ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/Foreach | Loops/Foreach | Loop through and print each element in a collection in order.
Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downward for... | #Swift | Swift | for i in [1,2,3] {
print(i)
} | Give a code snippet in #Swift
Loop through and print each element in a collection in order.
Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Non-continuous_subsequences | Non-continuous subsequences | Consider some sequence of elements. (It differs from a mere set of elements by having an ordering among members.)
A subsequence contains some subset of the elements of this sequence, in the same order.
A continuous subsequence is one in which no elements are missing between the first and last elements of the subseque... | #Nim | Nim | import sequtils
proc ncsub[T](se: seq[T], s = 0): seq[seq[T]] =
result = @[]
if se.len > 0:
let
x = se[0..0]
xs = se[1 .. ^1]
p2 = s mod 2
p1 = (s + 1) mod 2
for ys in ncsub(xs, s + p1):
result.add(x & ys)
result.add(ncsub(xs, s + p2))
elif s >= 3:
result.add(@[])
... | Give a code snippet in #Nim
Consider some sequence of elements. (It differs from a mere set of elements by having an ordering among members.)
A subsequence contains some subset of the elements of this sequence, in the same order.
A continuous subsequence is one in which no elements are missing between the first and ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Word_search | Word search | A word search puzzle typically consists of a grid of letters in which words are hidden.
There are many varieties of word search puzzles. For the task at hand we will use a rectangular grid in which the words may be placed horizontally, vertically, or diagonally. The words may also be spelled backwards.
The words may ... | #C.2B.2B | C++ |
#include <iomanip>
#include <ctime>
#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <fstream>
const int WID = 10, HEI = 10, MIN_WORD_LEN = 3, MIN_WORD_CNT = 25;
class Cell {
public:
Cell() : val( 0 ), cntOverlap( 0 ) {}
char val; int cntOverlap;
};
class Word {
public... | Give a code snippet in #C.2B.2B
A word search puzzle typically consists of a grid of letters in which words are hidden.
There are many varieties of word search puzzles. For the task at hand we will use a rectangular grid in which the words may be placed horizontally, vertically, or diagonally. The words may also be s... | christopher/rosetta-code | |
http://rosettacode.org/wiki/McNuggets_problem | McNuggets problem | Wikipedia
The McNuggets version of the coin problem was introduced by Henri Picciotto,
who included it in his algebra textbook co-authored with Anita Wah. Picciotto
thought of the application in the 1980s while dining with his son at
McDonald's, working the problem out on a napkin. A McNugget number is
the total number... | #Java | Java | public class McNuggets {
public static void main(String... args) {
int[] SIZES = new int[] { 6, 9, 20 };
int MAX_TOTAL = 100;
// Works like Sieve of Eratosthenes
int numSizes = SIZES.length;
int[] counts = new int[numSizes];
int maxFound = MAX_TOTAL + 1;
boo... | Give a code snippet in #Java
Wikipedia
The McNuggets version of the coin problem was introduced by Henri Picciotto,
who included it in his algebra textbook co-authored with Anita Wah. Picciotto
thought of the application in the 1980s while dining with his son at
McDonald's, working the problem out on a napkin. A McNug... | christopher/rosetta-code | |
http://rosettacode.org/wiki/RSA_code | RSA code | Given an RSA key (n,e,d), construct a program to encrypt and decrypt plaintext messages strings.
Background
RSA code is used to encode secret messages. It is named after Ron Rivest, Adi Shamir, and Leonard Adleman who published it at MIT in 1977. The advantage of this type of encryption is that you can distribute the... | #Rust | Rust |
extern crate num;
use num::bigint::BigUint;
use num::integer::Integer;
use num::traits::{One, Zero};
fn mod_exp(b: &BigUint, e: &BigUint, n: &BigUint) -> Result<BigUint, &'static str> {
if n.is_zero() {
return Err("modulus is zero");
}
if b >= n {
// base is too large and should be spl... | Give a code snippet in #Rust
Given an RSA key (n,e,d), construct a program to encrypt and decrypt plaintext messages strings.
Background
RSA code is used to encode secret messages. It is named after Ron Rivest, Adi Shamir, and Leonard Adleman who published it at MIT in 1977. The advantage of this type of encryption ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Averages/Simple_moving_average | Averages/Simple moving average | Computing the simple moving average of a series of numbers.
Task[edit]
Create a stateful function/class/instance that takes a period and returns a routine that takes a number as argument and returns a simple moving average of its arguments so far.
Description
A simple moving average is a method for computing an avera... | #zkl | zkl | fcn SMA(P){
fcn(n,ns,P){
sz:=ns.append(n.toFloat()).len();
if(P>sz) return(0.0);
if(P<sz) ns.del(0);
ns.sum(0.0)/P;
}.fp1(List.createLong(P+1),P) // pre-allocate a list of length P+1
} | Give a code snippet in #zkl
Computing the simple moving average of a series of numbers.
Task[edit]
Create a stateful function/class/instance that takes a period and returns a routine that takes a number as argument and returns a simple moving average of its arguments so far.
Description
A simple moving average is a ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Dot_product | Dot product | Task
Create a function/use an in-built function, to compute the dot product, also known as the scalar product of two vectors.
If possible, make the vectors of arbitrary length.
As an example, compute the dot product of the vectors:
[1, 3, -5] and
[4, -2, -1]
If implementing the dot ... | #Scheme | Scheme | (define (dot-product a b)
(apply + (map * a b)))
(display (dot-product '(1 3 -5) '(4 -2 -1)))
(newline) | Give a code snippet in #Scheme
Task
Create a function/use an in-built function, to compute the dot product, also known as the scalar product of two vectors.
If possible, make the vectors of arbitrary length.
As an example, compute the dot product of the vectors:
[1, 3, -5] and
[4, -2, -... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Hello_world/Text | Hello world/Text | Hello world/Text is part of Short Circuit's Console Program Basics selection.
Task
Display the string Hello world! on a text console.
Related tasks
Hello world/Graphical
Hello world/Line Printer
Hello world/Newbie
Hello world/Newline omission
Hello world/Standard error
Hello world/Web server
| #DWScript | DWScript |
PrintLn('Hello world!');
| Give a code snippet in #DWScript
Hello world/Text is part of Short Circuit's Console Program Basics selection.
Task
Display the string Hello world! on a text console.
Related tasks
Hello world/Graphical
Hello world/Line Printer
Hello world/Newbie
Hello world/Newline omission
Hello world/Standard erro... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Longest_common_subsequence | Longest common subsequence | Introduction
Define a subsequence to be any output string obtained by deleting zero or more symbols from an input string.
The Longest Common Subsequence (LCS) is a subsequence of maximum length common to two or more strings.
Let A ≡ A[0]… A[m - 1] and B ≡ B[0]… B[n - 1], m < n be strings drawn from an alphabet Σ of ... | #Rust | Rust |
use std::cmp;
fn lcs(string1: String, string2: String) -> (usize, String){
let total_rows = string1.len() + 1;
let total_columns = string2.len() + 1;
// rust doesn't allow accessing string by index
let string1_chars = string1.as_bytes();
let string2_chars = string2.as_bytes();
let mut tabl... | Give a code snippet in #Rust
Introduction
Define a subsequence to be any output string obtained by deleting zero or more symbols from an input string.
The Longest Common Subsequence (LCS) is a subsequence of maximum length common to two or more strings.
Let A ≡ A[0]… A[m - 1] and B ≡ B[0]… B[n - 1], m < n be string... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Van_Eck_sequence | Van Eck sequence | The sequence is generated by following this pseudo-code:
A: The first term is zero.
Repeatedly apply:
If the last term is *new* to the sequence so far then:
B: The next term is zero.
Otherwise:
C: The next term is how far back this last term occured previously.
Example
Using ... | #Quackery | Quackery | [ ' [ 0 ]
swap 1 - times
[ dup behead swap find
1+ 2dup swap found *
swap join ]
reverse ] is van-eck ( n --> [ )
10 van-eck echo cr
1000 van-eck -10 split echo drop | Give a code snippet in #Quackery
The sequence is generated by following this pseudo-code:
A: The first term is zero.
Repeatedly apply:
If the last term is *new* to the sequence so far then:
B: The next term is zero.
Otherwise:
C: The next term is how far back this last term occu... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Run-length_encoding | Run-length encoding | Run-length encoding
You are encouraged to solve this task according to the task description, using any language you may know.
Task
Given a string containing uppercase characters (A-Z), compress repeated 'runs' of the same character by storing the length of that run, and provide a function to reverse the compression... | #Delphi | Delphi |
program RunLengthTest;
{$APPTYPE CONSOLE}
uses
System.SysUtils;
type
TRLEPair = record
count: Integer;
letter: Char;
end;
TRLEncoded = TArray<TRLEPair>;
TRLEncodedHelper = record helper for TRLEncoded
public
procedure Clear;
function Add(c: Char): Integer;
procedure Encode(Da... | Give a code snippet in #Delphi
Run-length encoding
You are encouraged to solve this task according to the task description, using any language you may know.
Task
Given a string containing uppercase characters (A-Z), compress repeated 'runs' of the same character by storing the length of that run, and provide a fun... | 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... | #C.2B.2B | C++ | #include <iostream>
#include <ostream>
#include <set>
#include <vector>
template<typename T>
std::ostream& operator<<(std::ostream& os, const std::vector<T>& v) {
auto i = v.cbegin();
auto e = v.cend();
os << '[';
if (i != e) {
os << *i;
i = std::next(i);
}
while (i != e) {
... | Give a code snippet in #C.2B.2B
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.
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Gaussian_elimination | Gaussian elimination | Task
Solve Ax=b using Gaussian elimination then backwards substitution.
A being an n by n matrix.
Also, x and b are n by 1 vectors.
To improve accuracy, please use partial pivoting and scaling.
See also
the Wikipedia entry: Gaussian elimination
| #Common_Lisp | Common Lisp |
(defmacro mapcar-1 (fn n list)
"Maps a function of two parameters where the first one is fixed, over a list"
`(mapcar #'(lambda (l) (funcall ,fn ,n l)) ,list) )
(defun gauss (m)
(labels
((redc (m) ; Reduce to triangular form
(if (null (cdr m))
m
(cons (car m) (mapcar-1 #'cons 0 (... | Give a code snippet in #Common_Lisp
Task
Solve Ax=b using Gaussian elimination then backwards substitution.
A being an n by n matrix.
Also, x and b are n by 1 vectors.
To improve accuracy, please use partial pivoting and scaling.
See also
the Wikipedia entry: Gaussian elimination
| christopher/rosetta-code |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.