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/Harshad_or_Niven_series | Harshad or Niven series | The Harshad or Niven numbers are positive integers ≥ 1 that are divisible by the sum of their digits.
For example, 42 is a Harshad number as 42 is divisible by (4 + 2) without remainder.
Assume that the series is defined as the numbers in increasing order.
Task
The task is to create a function/method/... | #C | C | #include <stdio.h>
static int digsum(int n)
{
int sum = 0;
do { sum += n % 10; } while (n /= 10);
return sum;
}
int main(void)
{
int n, done, found;
for (n = 1, done = found = 0; !done; ++n) {
if (n % digsum(n) == 0) {
if (found++ < 20) printf("%d ", n);
if (n >... | Give a code snippet in #C
The Harshad or Niven numbers are positive integers ≥ 1 that are divisible by the sum of their digits.
For example, 42 is a Harshad number as 42 is divisible by (4 + 2) without remainder.
Assume that the series is defined as the numbers in increasing order.
Task
The task is t... | 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... | #Tiny_BASIC | Tiny BASIC | PRINT "Open doors are:"
LET I = 1
10 IF I = 100 THEN END
rem funcion SQR
LET B = I*I
rem funcion MODULO
LET A = I - (I / B) * B
IF A < 11 THEN PRINT B
LET I = I + 1
GOTO 10 | Give a code snippet in #Tiny_BASIC
There are 100 doors in a row that are all initially closed.
You make 100 passes by the doors.
The first time through, visit every door and toggle the door (if the door is closed, open it; if it is open, close it).
The second time, only visit every 2nd door (door #2, #4, #... | christopher/rosetta-code | |
http://rosettacode.org/wiki/De_Bruijn_sequences | de Bruijn sequences | The sequences are named after the Dutch mathematician Nicolaas Govert de Bruijn.
A note on Dutch capitalization: Nicolaas' last name is de Bruijn, the de isn't normally capitalized
unless it's the first word in a sentence. Rosetta Code (more or less by default or by fiat) requires the first word in the... | #Ada | Ada | with Ada.Text_IO; use Ada.Text_IO;
with Ada.Strings.Fixed; use Ada.Strings;
with Ada.Strings.Unbounded;
procedure De_Bruijn_Sequences is
function De_Bruijn (K, N : Positive) return String
is
use Ada.Strings.Unbounded;
Alphabet : constant String := "0123456789";
subtyp... | Give a code snippet in #Ada
The sequences are named after the Dutch mathematician Nicolaas Govert de Bruijn.
A note on Dutch capitalization: Nicolaas' last name is de Bruijn, the de isn't normally capitalized
unless it's the first word in a sentence. Rosetta Code (more or less by default or by fiat) r... | christopher/rosetta-code | |
http://rosettacode.org/wiki/99_bottles_of_beer | 99 bottles of beer | Task
Display the complete lyrics for the song: 99 Bottles of Beer on the Wall.
The beer song
The lyrics follow this form:
99 bottles of beer on the wall
99 bottles of beer
Take one down, pass it around
98 bottles of beer on the wall
98 bottles of beer on the wall
98 bottles of beer
Take one dow... | #hexiscript | hexiscript | fun bottles amount beverage location
let bottle " bottles of "
if amount = 0; let amount "No more"
elif amount = 1; let bottle " bottle of "; endif
return amount + bottle + beverage + " " + location
endfun
fun take amount location
return "Take " + amount + " " + location
endfun
fun pass entity destinati... | Give a code snippet in #hexiscript
Task
Display the complete lyrics for the song: 99 Bottles of Beer on the Wall.
The beer song
The lyrics follow this form:
99 bottles of beer on the wall
99 bottles of beer
Take one down, pass it around
98 bottles of beer on the wall
98 bottles of beer on the wall... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Pi | Pi |
Create a program to continually calculate and output the next decimal digit of
π
{\displaystyle \pi }
(pi).
The program should continue forever (until it is aborted by the user) calculating and outputting each decimal digit in succession.
The output should be a decimal sequence beginning 3.14159265 ...... | #Go | Go | package main
import (
"fmt"
"math/big"
)
type lft struct {
q,r,s,t big.Int
}
func (t *lft) extr(x *big.Int) *big.Rat {
var n, d big.Int
var r big.Rat
return r.SetFrac(
n.Add(n.Mul(&t.q, x), &t.r),
d.Add(d.Mul(&t.s, x), &t.t))
}
var three = big.NewInt(3)
var four = big.New... | Give a code snippet in #Go
Create a program to continually calculate and output the next decimal digit of
π
{\displaystyle \pi }
(pi).
The program should continue forever (until it is aborted by the user) calculating and outputting each decimal digit in succession.
The output should be a decimal sequenc... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Colour_pinstripe/Printer | Colour pinstripe/Printer | The task is to create 1 point wide colour vertical pinstripes with a sufficient number of pinstripes to span the entire width of the colour graphics printer. The pinstripes should alternate between each individual cartridge ink and ink pair and black and white pinstripes should be included. A typical pinstripe sequence... | #BBC_BASIC | BBC BASIC | PD_RETURNDC = 256
_LOGPIXELSY = 90
DIM pd{lStructSize%, hwndOwner%, hDevMode%, hDevNames%, \
\ hdc%, flags%, nFromPage{l&,h&}, nToPage{l&,h&}, \
\ nMinPage{l&,h&}, nMaxPage{l&,h&}, nCopies{l&,h&}, \
\ hInstance%, lCustData%, lpfnPrintHook%, lpfnSetupHook%, \
\ ... | Give a code snippet in #BBC_BASIC
The task is to create 1 point wide colour vertical pinstripes with a sufficient number of pinstripes to span the entire width of the colour graphics printer. The pinstripes should alternate between each individual cartridge ink and ink pair and black and white pinstripes should be inc... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Abundant,_deficient_and_perfect_number_classifications | Abundant, deficient and perfect number classifications | These define three classifications of positive integers based on their proper divisors.
Let P(n) be the sum of the proper divisors of n where the proper divisors are all positive divisors of n other than n itself.
if P(n) < n then n is classed as deficient (OEIS A005100).
if P(n)... | #VTL-2 | VTL-2 | 10 M=20000
20 I=1
30 :I)=0
40 I=I+1
50 #=M>I*30
60 I=1
70 J=I*2
80 :J)=:J)+I
90 J=J+I
100 #=M>J*80
110 I=I+1
120 #=M/2>I*70
130 D=0
140 P=0
150 A=0
160 I=1
170 #=:I)<I*230
180 #=:I)=I*210
190 A=A+1
200 #=240
210 P=P+1
220 #=240
230 D=D+1
240 I=I+1
250 #=M>I*170
260 ?=D
270 ?=" deficient"
280 ?=P
290 ?=" perfect"
300 ?=... | Give a code snippet in #VTL-2
These define three classifications of positive integers based on their proper divisors.
Let P(n) be the sum of the proper divisors of n where the proper divisors are all positive divisors of n other than n itself.
if P(n) < n then n is classed as deficient... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Almost_prime | Almost prime | A k-Almost-prime is a natural number
n
{\displaystyle n}
that is the product of
k
{\displaystyle k}
(possibly identical) primes.
Example
1-almost-primes, where
k
=
1
{\displaystyle k=1}
, are the prime numbers themselves.
2-almost-primes, where
k
=
2
{\displaystyl... | #Wren | Wren | var kPrime = Fn.new { |n, k|
var nf = 0
var i = 2
while (i <= n) {
while (n%i == 0) {
if (nf == k) return false
nf = nf + 1
n = (n/i).floor
}
i = i + 1
}
return nf == k
}
var gen = Fn.new { |k, n|
var r = List.filled(n, 0)
n = 2
... | Give a code snippet in #Wren
A k-Almost-prime is a natural number
n
{\displaystyle n}
that is the product of
k
{\displaystyle k}
(possibly identical) primes.
Example
1-almost-primes, where
k
=
1
{\displaystyle k=1}
, are the prime numbers themselves.
2-almost-primes, whe... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Write_entire_file | Write entire file | Task
(Over)write a file so that it contains a string.
The reverse of Read entire file—for when you want to update or create a file which you would read in its entirety all at once.
| #D | D | import std.stdio;
void main() {
auto file = File("new.txt", "wb");
file.writeln("Hello World!");
} | Give a code snippet in #D
Task
(Over)write a file so that it contains a string.
The reverse of Read entire file—for when you want to update or create a file which you would read in its entirety all at once.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Aliquot_sequence_classifications | Aliquot sequence classifications | An aliquot sequence of a positive integer K is defined recursively as the first member
being K and subsequent members being the sum of the Proper divisors of the previous term.
If the terms eventually reach 0 then the series for K is said to terminate.
There are several classifications for non termination:
If the s... | #ALGOL_68 | ALGOL 68 | BEGIN
# aliquot sequence classification #
# maximum sequence length we consider #
INT max sequence length = 16;
# possible classifications #
STRING perfect classificatio... | Give a code snippet in #ALGOL_68
An aliquot sequence of a positive integer K is defined recursively as the first member
being K and subsequent members being the sum of the Proper divisors of the previous term.
If the terms eventually reach 0 then the series for K is said to terminate.
There are several classificati... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Number_names | Number names | Task
Show how to spell out a number in English.
You can use a preexisting implementation or roll your own, but you should support inputs up to at least one million (or the maximum value of your language's default bounded integer type, if that's less).
Support for inputs other than positive integers (like zero, negat... | #VBA | VBA | Public twenties As Variant
Public decades As Variant
Public orders As Variant
Private Sub init()
twenties = [{"zero","one","two","three","four","five","six","seven","eight","nine","ten", "eleven","twelve","thirteen","fourteen","fifteen","sixteen","seventeen","eighteen","nineteen"}]
decades = [{"twenty","thirt... | Give a code snippet in #VBA
Task
Show how to spell out a number in English.
You can use a preexisting implementation or roll your own, but you should support inputs up to at least one million (or the maximum value of your language's default bounded integer type, if that's less).
Support for inputs other than positi... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Hamming_numbers | Hamming numbers | Hamming numbers are numbers of the form
H = 2i × 3j × 5k
where
i, j, k ≥ 0
Hamming numbers are also known as ugly numbers and also 5-smooth numbers (numbers whose prime divisors are less or equal to 5).
Task
Generate the sequence of Hamming numbers, in increasing order. In ... | #MUMPS | MUMPS | Hamming(n) New count,ok,next,number,which
For which=2,3,5 Set number=1
For count=1:1:n Do
. Set ok=0 Set:count<21 ok=1 Set:count=1691 ok=1 Set:count=n ok=1
. Write:ok !,$Justify(count,5),": ",number
. For which=2,3,5 Set next(number*which)=which
. Set number=$Order(next(""))
. Kill next(number)
. Quit
Quit
Do ... | Give a code snippet in #MUMPS
Hamming numbers are numbers of the form
H = 2i × 3j × 5k
where
i, j, k ≥ 0
Hamming numbers are also known as ugly numbers and also 5-smooth numbers (numbers whose prime divisors are less or equal to 5).
Task
Generate the sequence of Hamming numb... | christopher/rosetta-code | |
http://rosettacode.org/wiki/The_Twelve_Days_of_Christmas | The Twelve Days of Christmas | Task
Write a program that outputs the lyrics of the Christmas carol The Twelve Days of Christmas.
The lyrics can be found here.
(You must reproduce the words in the correct order, but case, format, and punctuation are left to your discretion.)
Other tasks related to string operations:
Metrics
Array length
Stri... | #ALGOL_68 | ALGOL 68 | BEGIN
[]STRING labels = ("first", "second", "third", "fourth",
"fifth", "sixth", "seventh", "eighth",
"ninth", "tenth", "eleventh", "twelfth");
[]STRING gifts = ("A partridge in a pear tree.",
"Two turtle doves, and",
"Three F... | Give a code snippet in #ALGOL_68
Task
Write a program that outputs the lyrics of the Christmas carol The Twelve Days of Christmas.
The lyrics can be found here.
(You must reproduce the words in the correct order, but case, format, and punctuation are left to your discretion.)
Other tasks related to string operat... | 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 ... | #AWK | AWK |
# syntax: GAWK -f STRIP_CONTROL_CODES_AND_EXTENDED_CHARACTERS.AWK
BEGIN {
s = "ab\xA2\x09z" # a b cent tab z
printf("original string: %s (length %d)\n",s,length(s))
gsub(/[\x00-\x1F\x7F]/,"",s); printf("control characters stripped: %s (length %d)\n",s,length(s))
gsub(/[\x80-\xFF]/,"",s); printf("contr... | Give a code snippet in #AWK
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
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Percolation/Site_percolation | Percolation/Site percolation |
Percolation Simulation
This is a simulation of aspects of mathematical percolation theory.
For other percolation simulations, see Category:Percolation Simulations, or:
1D finite grid simulation
Mean run density
2D finite grid simulations
Site percolation | Bond percolation | Mean cluster density
Given an
M
×
N... | #Wren | Wren | import "random" for Random
import "/fmt" for Fmt
var rand = Random.new()
var RAND_MAX = 32767
var EMPTY = ""
var x = 15
var y = 15
var grid = List.filled((x + 1) * (y + 1) + 1, EMPTY)
var cell = 0
var end = 0
var m = 0
var n = 0
var makeGrid = Fn.new { |p|
var thresh = (p * RAND_MAX).truncate
m = x
n ... | Give a code snippet in #Wren
Percolation Simulation
This is a simulation of aspects of mathematical percolation theory.
For other percolation simulations, see Category:Percolation Simulations, or:
1D finite grid simulation
Mean run density
2D finite grid simulations
Site percolation | Bond percolation | Mean clust... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Safe_addition | Safe addition | Implementation of interval arithmetic and more generally fuzzy number arithmetic require operations that yield safe upper and lower bounds of the exact result.
For example, for an addition, it is the operations +↑ and +↓ defined as: a +↓ b ≤ a + b ≤ a +↑ b.
Additionally it is desired that the widt... | #Scala | Scala | object SafeAddition extends App {
val (a, b) = (1.2, 0.03)
val result = safeAdd(a, b)
private def safeAdd(a: Double, b: Double) = Seq(stepDown(a + b), stepUp(a + b))
private def stepDown(d: Double) = Math.nextAfter(d, Double.NegativeInfinity)
private def stepUp(d: Double) = Math.nextUp(d)
println(f"... | Give a code snippet in #Scala
Implementation of interval arithmetic and more generally fuzzy number arithmetic require operations that yield safe upper and lower bounds of the exact result.
For example, for an addition, it is the operations +↑ and +↓ defined as: a +↓ b ≤ a + b ≤ a +↑ b.
Additiona... | 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 ... | #EchoLisp | EchoLisp |
;; shuffler : a permutation vector which interleaves both halves of deck
(define (make-shuffler n)
(let ((s (make-vector n)))
(for ((i (in-range 0 n 2))) (vector-set! s i (/ i 2)))
(for ((i (in-range 0 n 2))) (vector-set! s (1+ i) (+ (/ n 2) (vector-ref s i))))
s))
;; output : (n . # of shuffles needed to ... | Give a code snippet in #EchoLisp
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/N-queens_problem | N-queens problem |
Solve the eight queens puzzle.
You can extend the problem to solve the puzzle with a board of size NxN.
For the number of solutions for small values of N, see OEIS: A000170.
Related tasks
A* search algorithm
Solve a Hidato puzzle
Solve a Holy Knight's tour
Knight's tour
Peaceful chess queen armie... | #Frink | Frink | solution[board] :=
{
for q = 0 to length[board] - 1
for c = q+1 to length[board] - 1
if board@q == board@c + (c - q) or board@q == board@c - (c - q)
return false
return true
}
for b = array[1 to 8].permute[]
if solution[b]
println[b] | Give a code snippet in #Frink
Solve the eight queens puzzle.
You can extend the problem to solve the puzzle with a board of size NxN.
For the number of solutions for small values of N, see OEIS: A000170.
Related tasks
A* search algorithm
Solve a Hidato puzzle
Solve a Holy Knight's tour
Knight's t... | christopher/rosetta-code | |
http://rosettacode.org/wiki/N-queens_problem | N-queens problem |
Solve the eight queens puzzle.
You can extend the problem to solve the puzzle with a board of size NxN.
For the number of solutions for small values of N, see OEIS: A000170.
Related tasks
A* search algorithm
Solve a Hidato puzzle
Solve a Holy Knight's tour
Knight's tour
Peaceful chess queen armie... | #VBScript | VBScript | 'N-queens problem - non recursive & structured - vbs - 24/02/2017
const l=15
dim a(),s(),u(): redim a(l),s(l),u(4*l-2)
for i=1 to l: a(i)=i: next
for n=1 to l
m=0
i=1
j=0
r=2*n-1
Do
i=i-1
j=j+1
p=0
q=-r
Do
i=i+1
u(p)=1
u(q+r... | Give a code snippet in #VBScript
Solve the eight queens puzzle.
You can extend the problem to solve the puzzle with a board of size NxN.
For the number of solutions for small values of N, see OEIS: A000170.
Related tasks
A* search algorithm
Solve a Hidato puzzle
Solve a Holy Knight's tour
Knight'... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Find_the_last_Sunday_of_each_month | Find the last Sunday of each month | Write a program or a script that returns the last Sundays of each month of a given year. The year may be given through any simple input method in your language (command line, std in, etc).
Example of an expected output:
./last_sundays 2013
2013-01-27
2013-02-24
2013-03-31
2013-04-28
2013-05-26
2013-06-30
2013-07-28
2... | #Befunge | Befunge | ":raeY",,,,,&>55+,:::45*:*%\"d"%!*\4%+!3v
v2++6**"I"5\+/*:*54\-/"d"\/4::-1::p53+g5<
>:00p5g4-+7%\:0\v>,"-",5g+:55+/68*+,55+%v
^<<_$$vv*86%+55:<^+*86%+55,+*86/+55:-1:<6
>$$^@$<>+\55+/:#^_$>:#,_$"-",\:04-\-00g^8
^<# #"#"##"#"##!` +76:+1g00,+55,+*< | Give a code snippet in #Befunge
Write a program or a script that returns the last Sundays of each month of a given year. The year may be given through any simple input method in your language (command line, std in, etc).
Example of an expected output:
./last_sundays 2013
2013-01-27
2013-02-24
2013-03-31
2013-04-28
2... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Constrained_genericity | Constrained genericity | Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can call the function eat on it.
Write a ... | #PicoLisp | PicoLisp | (class +Eatable)
(dm eat> ()
(prinl "I'm eatable") )
(class +FoodBox)
# obj
(dm set> (Obj)
(unless (method 'eat> Obj) # Check if the object is eatable
(quit "Object is not eatable" Obj) )
(=: obj Obj) ) # If so, set the object
(let (Box (new '(+FoodBo... | Give a code snippet in #PicoLisp
Constrained genericity or bounded quantification means
that a parametrized type or function (see parametric polymorphism)
can only be instantiated on types fulfilling some conditions,
even if those conditions are not used in that function.
Say a type is called "eatable" if you can cal... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Test_integerness | Test integerness | Mathematically,
the integers Z are included in the rational numbers Q,
which are included in the real numbers R,
which can be generalized to the complex numbers C.
This means that each of those larger sets, and the data types used to represent them, include some integers.
Task[edit]
Given a rational, real, or co... | #Racket | Racket | #lang racket
(require tests/eli-tester)
(test ;; known representations of integers:
;; - as exacts
(integer? -1) => #t
(integer? 0) => #t
(integer? 1) => #t
(integer? 1234879378539875943875937598379587539875498792424323432432343242423432432) => #t
(integer? -123487937853987594387593759837958753987549879242... | Give a code snippet in #Racket
Mathematically,
the integers Z are included in the rational numbers Q,
which are included in the real numbers R,
which can be generalized to the complex numbers C.
This means that each of those larger sets, and the data types used to represent them, include some integers.
Task[edi... | 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.
| #Ursa | Ursa | decl file f
f.delete "input.txt"
f.delete "docs"
f.delete "/input.txt"
f.delete "/docs" | Give a code snippet in #Ursa
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/XML/Output | XML/Output | Create a function that takes a list of character names and a list of corresponding remarks and returns an XML document of <Character> elements each with a name attributes and each enclosing its remarks.
All <Character> elements are to be enclosed in turn, in an outer <CharacterRemarks> element.
As an example, calling ... | #TUSCRIPT | TUSCRIPT |
$$ MODE TUSCRIPT
STRUCTURE xmloutput
DATA '<CharacterRemarks>'
DATA * ' <Character name="' names +'">' remarks +'</Character>'
DATA = '</CharacterRemarks>'
ENDSTRUCTURE
BUILD X_TABLE entitysubst=" >> > << < & & "
ERROR/STOP CREATE ("dest",seq-o,-std-)
ACCESS d: WRITE/ERASE/STRUCTURE "dest" num,str
str="xm... | Give a code snippet in #TUSCRIPT
Create a function that takes a list of character names and a list of corresponding remarks and returns an XML document of <Character> elements each with a name attributes and each enclosing its remarks.
All <Character> elements are to be enclosed in turn, in an outer <CharacterRemarks>... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Search_a_list_of_records | Search a list of records | Many programming languages provide convenient ways to look for a known value in a simple list of strings or numbers.
But what if the elements of the list are themselves compound records/objects/data-structures, and the search condition is more complex than a simple equality test?
Task[edit]
Write a function/method/et... | #EchoLisp | EchoLisp |
(require 'struct)
(require 'json)
;; importing data
(define cities
#<<
[{"name":"Lagos", "population":21}, {"name":"Cairo", "population":15.2}, {"name":"Kinshasa-Brazzaville", "population":11.3}, {"name":"Greater Johannesburg", "population":7.55}, {"name":"Mogadishu", "population":5.85}, {"name":"Khartoum-Omdurman"... | Give a code snippet in #EchoLisp
Many programming languages provide convenient ways to look for a known value in a simple list of strings or numbers.
But what if the elements of the list are themselves compound records/objects/data-structures, and the search condition is more complex than a simple equality test?
Tas... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Ramanujan%27s_constant | Ramanujan's constant | Calculate Ramanujan's constant (as described on the OEIS site) with at least
32 digits of precision, by the method of your choice. Optionally, if using the 𝑒**(π*√x) approach,
show that when evaluated with the last four Heegner numbers
the result is almost an integer.
| #Pari.2FGP | Pari/GP | \p 50
exp(Pi*sqrt(163)) | Give a code snippet in #Pari.2FGP
Calculate Ramanujan's constant (as described on the OEIS site) with at least
32 digits of precision, by the method of your choice. Optionally, if using the 𝑒**(π*√x) approach,
show that when evaluated with the last four Heegner numbers
the result is almost an integer.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Literals/String | Literals/String | Task
Show literal specification of characters and strings.
If supported, show how the following work:
verbatim strings (quotes where escape sequences are quoted literally)
here-strings
Also, discuss which quotes expand variables.
Related tasks
Special characters
Here document
Other tasks r... | #UNIX_Shell | UNIX Shell | echo "The boy said 'hello'."
echo 'The girl said "hello" too.' | Give a code snippet in #UNIX_Shell
Task
Show literal specification of characters and strings.
If supported, show how the following work:
verbatim strings (quotes where escape sequences are quoted literally)
here-strings
Also, discuss which quotes expand variables.
Related tasks
Special characte... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Number_reversal_game | Number reversal game | Task
Given a jumbled list of the numbers 1 to 9 that are definitely not in
ascending order.
Show the list, and then ask the player how many digits from the
left to reverse.
Reverse those digits, then ask again, until all the digits end up in ascending order.
The score is the count of the reversa... | #HicEst | HicEst | WRITE(Messagebox) "You took ", Reversals(), " attempts"
FUNCTION Reversals()
DIMENSION digits(9), temp(9)
digits = 0
DO i = 1, 9 ! create the shuffled digits
1 x = CEILING( RAN(9) )
IF( INDEX(digits, x) ) GOTO 1 ! HicEst has no WHILE
digits(i) = x
ENDDO
DO Reversals = 1, 1E6 ! HicEst nee... | Give a code snippet in #HicEst
Task
Given a jumbled list of the numbers 1 to 9 that are definitely not in
ascending order.
Show the list, and then ask the player how many digits from the
left to reverse.
Reverse those digits, then ask again, until all the digits end up in ascending order.
The s... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Eertree | Eertree | An eertree is a data structure designed for efficient processing of certain palindrome tasks, for instance counting the number of sub-palindromes in an input string.
The data structure has commonalities to both tries and suffix trees.
See links below.
Task
Construct an eertree for the string "eertree", then outp... | #Wren | Wren | class Node {
construct new() {
_edges = {} // edges (or forward links)
_link = null // suffix link (backward links)
_len = 0 // the length of the node
}
edges { _edges }
link { _link }
link=(l) { _link = l }
len { _len }
len=(l) { _len = l }
... | Give a code snippet in #Wren
An eertree is a data structure designed for efficient processing of certain palindrome tasks, for instance counting the number of sub-palindromes in an input string.
The data structure has commonalities to both tries and suffix trees.
See links below.
Task
Construct an eertree for t... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Introspection | Introspection | Task
verify the version/revision of your currently running (compiler/interpreter/byte-compiler/runtime environment/whatever your language uses) and exit if it is too old.
check whether the variable "bloop" exists and whether the math-function "abs()" is available and if yes compute abs(bloop).
Extra credit
Repor... | #Aikido | Aikido |
import math
if (version < 144) {
throw "Version of aikido is too old"
}
var bloop = -1.4
// Math package doesn't have 'abs'. We'll use 'fabs' instead.
if ("fabs" in Math) {
if ("bloop" in main) {
println ("fabs(bloop) is " + eval ("Math.fabs(bloop)"))
}
}
var x = 104
var y = 598
var z = "... | Give a code snippet in #Aikido
Task
verify the version/revision of your currently running (compiler/interpreter/byte-compiler/runtime environment/whatever your language uses) and exit if it is too old.
check whether the variable "bloop" exists and whether the math-function "abs()" is available and if yes compute ab... | 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 ... | #Pike | Pike | > string input = random_string(100);
> (string)((array)input-enumerate(32)-enumerate(255-126,1,127));
Result: "p_xx08M]cK<FHgR3\\I.x>)Tm<VgakYddy&P7" | Give a code snippet in #Pike
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
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Last_Friday_of_each_month | Last Friday of each month | Task
Write a program or a script that returns the date of the last Fridays of each month of a given year.
The year may be given through any simple input method in your language (command line, std in, etc).
Example of an expected output:
./last_fridays 2012
2012-01-27
2012-02-24
2012-03-30
2012-04-27
2012-05-25
20... | #Oforth | Oforth | import: date
: lastFridays(y)
| m |
Date.JANUARY Date.DECEMBER for: m [
Date newDate(y, m, Date.DaysInMonth(y, m))
while(dup dayOfWeek Date.FRIDAY <>) [ addDays(-1) ]
println
] ; | Give a code snippet in #Oforth
Task
Write a program or a script that returns the date of the last Fridays of each month of a given year.
The year may be given through any simple input method in your language (command line, std in, etc).
Example of an expected output:
./last_fridays 2012
2012-01-27
2012-02-24
201... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Arithmetic-geometric_mean/Calculate_Pi | Arithmetic-geometric mean/Calculate Pi | Almkvist Berndt 1988 begins with an investigation of why the agm is such an efficient algorithm, and proves that it converges quadratically. This is an efficient method to calculate
π
{\displaystyle \pi }
.
With the same notations used in Arithmetic-geometric mean, we can summarize the paper by writing:
π
... | #OCaml | OCaml | let limit = 10000 and n = 2800
let x = Array.make (n+1) 2000
let rec g j sum =
if j < 1 then sum else
let sum = sum * j + limit * x.(j) in
x.(j) <- sum mod (j * 2 - 1);
g (j - 1) (sum / (j * 2 - 1))
let rec f i carry =
if i = 0 then () else
let sum = g i 0 in
Printf.printf "%04d" (carry + su... | Give a code snippet in #OCaml
Almkvist Berndt 1988 begins with an investigation of why the agm is such an efficient algorithm, and proves that it converges quadratically. This is an efficient method to calculate
π
{\displaystyle \pi }
.
With the same notations used in Arithmetic-geometric mean, we can summariz... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Spinning_rod_animation/Text | Spinning rod animation/Text | Task
An animation with the following frames in the following order (if certain characters aren't available or can't be used correctly in the programming language, alternate characters can replace any of these frames) must animate with a delay of 0.25 seconds between each frame, with the previous frame being cleared be... | #Phix | Phix | without js -- (cursor, sleep)
puts(1,"please_wait... ")
cursor(NO_CURSOR)
for i=1 to 10 do -- (approx 10 seconds)
for j=1 to 4 do
printf(1," \b%c\b",`|/-\`[j])
sleep(0.25)
end for
end for
puts(1," \ndone") -- clear rod, "done" on next line
| Give a code snippet in #Phix
Task
An animation with the following frames in the following order (if certain characters aren't available or can't be used correctly in the programming language, alternate characters can replace any of these frames) must animate with a delay of 0.25 seconds between each frame, with the p... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Start_from_a_main_routine | Start from a main routine |
Some languages (like Gambas and Visual Basic) support two startup modes. Applications written in these languages start with an open window that waits for events, and it is necessary to do some trickery to cause a main procedure to run instead. Data driven or event driven languages may also require similar tricker... | #Clojure | Clojure |
MODULE MainProcedure;
IMPORT StdLog;
PROCEDURE Do*;
BEGIN
StdLog.String("From Do");StdLog.Ln
END Do;
PROCEDURE Main*;
BEGIN
StdLog.String("From Main");StdLog.Ln
END Main;
END MainProcedure.
| Give a code snippet in #Clojure
Some languages (like Gambas and Visual Basic) support two startup modes. Applications written in these languages start with an open window that waits for events, and it is necessary to do some trickery to cause a main procedure to run instead. Data driven or event driven languages... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Host_introspection | Host introspection | Print the word size and endianness of the host machine.
See also: Variable size/Get
| #XPL0 | XPL0 | include c:\cxpl\codes; \intrinsic 'code' declarations
int A, B;
char C;
[IntOut(0, @B-@A); CrLf(0); \word size = integer size
A:= $1234;
C:= @A;
Text(0, if C(0)=$34 then "Little" else "Big");
Text(0, " endian
");
] | Give a code snippet in #XPL0
Print the word size and endianness of the host machine.
See also: Variable size/Get
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Y_combinator | Y combinator | In strict functional programming and the lambda calculus, functions (lambda expressions) don't have state and are only allowed to refer to arguments of enclosing functions.
This rules out the usual definition of a recursive function wherein a function is associated with the state of a variable and this variable's stat... | #Maple | Maple |
> Y:=f->(x->x(x))(g->f((()->g(g)(args)))):
> Yfac:=Y(f->(x->`if`(x<2,1,x*f(x-1)))):
> seq( Yfac( i ), i = 1 .. 10 );
1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800
> Yfib:=Y(f->(x->`if`(x<2,x,f(x-1)+f(x-2)))):
> seq( Yfib( i ), i = 1 .. 10 );
1, 1, 2, 3, 5, 8, 13, 21, 34, 55
| Give a code snippet in #Maple
In strict functional programming and the lambda calculus, functions (lambda expressions) don't have state and are only allowed to refer to arguments of enclosing functions.
This rules out the usual definition of a recursive function wherein a function is associated with the state of a va... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Respond_to_an_unknown_method_call | Respond to an unknown method call | Task
Demonstrate how to make the object respond (sensibly/usefully) to an invocation of a method on it that it does not support through its class definitions.
Note that this is not the same as just invoking a defined method whose name is given dynamically; the method named at the point of invocation must not be defin... | #M2000_Interpreter | M2000 Interpreter |
module checkit {
Class Alfa {
k=1000
module a (x, y) {
Print x, y
}
module NoParam {
Print "ok"
}
Function Sqr(x) {
=Sqrt(x)
}
Function NoParam {
... | Give a code snippet in #M2000_Interpreter
Task
Demonstrate how to make the object respond (sensibly/usefully) to an invocation of a method on it that it does not support through its class definitions.
Note that this is not the same as just invoking a defined method whose name is given dynamically; the method named a... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Yin_and_yang | Yin and yang | One well-known symbol of the philosophy of duality known as yin and yang is the taijitu.
Task
Create a function that, given a parameter representing size, generates such a symbol scaled to the requested size.
Generate and display the symbol for two different (small) sizes.
| #D | D | import std.stdio, std.algorithm, std.array, std.math, std.range,
std.conv, std.typecons;
string yinYang(in int n) pure /*nothrow @safe*/ {
enum : char { empty = ' ', white = '.', black = '#' }
const radii = [1, 3, 6].map!(i => i * n).array;
auto ranges = radii.map!(r => iota(-r, r + 1).array).arr... | Give a code snippet in #D
One well-known symbol of the philosophy of duality known as yin and yang is the taijitu.
Task
Create a function that, given a parameter representing size, generates such a symbol scaled to the requested size.
Generate and display the symbol for two different (small) sizes.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Increasing_gaps_between_consecutive_Niven_numbers | Increasing gaps between consecutive Niven numbers | Note: Niven numbers are also called Harshad numbers.
They are also called multidigital numbers.
Niven numbers are positive integers which are evenly divisible by the sum of its
digits (expressed in base ten).
Evenly divisible means divisible with no remainder.
Task
find the gap (differen... | #Haskell | Haskell | {-# LANGUAGE NumericUnderscores #-}
import Control.Monad (guard)
import Text.Printf (printf)
import Data.List (intercalate, unfoldr)
import Data.List.Split (chunksOf)
import Data.Tuple (swap)
nivens :: [Int]
nivens = [1..] >>= \n -> guard (n `rem` digitSum n == 0) >> [n]
where
digitSum = sum . unfoldr (\x -> guard... | Give a code snippet in #Haskell
Note: Niven numbers are also called Harshad numbers.
They are also called multidigital numbers.
Niven numbers are positive integers which are evenly divisible by the sum of its
digits (expressed in base ten).
Evenly divisible means divisible with no remainder.
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Create_a_two-dimensional_array_at_runtime | Create a two-dimensional array at runtime |
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Get two integers from the user, then create a two-dimensional array where the two dimensions have the sizes given by those numbers, and which can be accessed ... | #ooRexx | ooRexx | Say "enter first dimension"
pull d1
say "enter the second dimension"
pull d2
a = .array~new(d1, d2)
a[1, 1] = "Abc"
say a[1, 1]
say d1 d2 a[d1,d2]
say a[10,10]
max=1000000000
b = .array~new(max,max) | 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.
Get two integers from the user, then create a two-dimensional array where the two dimensions have the sizes given by those num... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Ackermann_function | Ackermann function | The Ackermann function is a classic example of a recursive function, notable especially because it is not a primitive recursive function. It grows very quickly in value, as does the size of its call tree.
The Ackermann function is usually defined as follows:
A
(
m
,
n
)
=
{
n
+
1
if
m
=
0
A
(
m
... | #GAP | GAP | ack := function(m, n)
if m = 0 then
return n + 1;
elif (m > 0) and (n = 0) then
return ack(m - 1, 1);
elif (m > 0) and (n > 0) then
return ack(m - 1, ack(m, n - 1));
else
return fail;
fi;
end; | Give a code snippet in #GAP
The Ackermann function is a classic example of a recursive function, notable especially because it is not a primitive recursive function. It grows very quickly in value, as does the size of its call tree.
The Ackermann function is usually defined as follows:
A
(
m
,
n
)
=
{
n... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Read_entire_file | Read entire file | Task
Load the entire contents of some text file as a single string variable.
If applicable, discuss: encoding selection, the possibility of memory-mapping.
Of course, in practice one should avoid reading an entire file at once
if the file is large and the task can be accomplished incrementally instead
(in which case... | #Kotlin | Kotlin | import java.io.File
fun main(args: Array<String>) {
println(File("unixdict.txt").readText(charset = Charsets.UTF_8))
} | Give a code snippet in #Kotlin
Task
Load the entire contents of some text file as a single string variable.
If applicable, discuss: encoding selection, the possibility of memory-mapping.
Of course, in practice one should avoid reading an entire file at once
if the file is large and the task can be accomplished incr... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Program_name | Program name | The task is to programmatically obtain the name used to invoke the program. (For example determine whether the user ran "python hello.py", or "python hellocaller.py", a program importing the code from "hello.py".)
Sometimes a multiline shebang is necessary in order to provide the script name to a language's internal A... | #Factor | Factor | #! /usr/bin/env factor
USING: namespaces io command-line ;
IN: scriptname
: main ( -- ) script get print ;
MAIN: main | Give a code snippet in #Factor
The task is to programmatically obtain the name used to invoke the program. (For example determine whether the user ran "python hello.py", or "python hellocaller.py", a program importing the code from "hello.py".)
Sometimes a multiline shebang is necessary in order to provide the script... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Array_concatenation | Array concatenation | Task
Show how to concatenate two arrays in your language.
If this is as simple as array1 + array2, so be it.
| #Frink | Frink |
a = [1,2]
b = [3,4]
a.pushAll[b]
| Give a code snippet in #Frink
Task
Show how to concatenate two arrays in your language.
If this is as simple as array1 + array2, so be it.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/MAC_Vendor_Lookup | MAC Vendor Lookup | Every connected device around the world comes with a unique Media Access Control address, or a MAC address.
A common task a network administrator may come across is being able to identify a network device's manufacturer when given only a MAC address.
Task
Interface with one (or numerous) APIs that exist on the i... | #Red | Red | print read rejoin [http://api.macvendors.com/ ask "MAC address: "]
| Give a code snippet in #Red
Every connected device around the world comes with a unique Media Access Control address, or a MAC address.
A common task a network administrator may come across is being able to identify a network device's manufacturer when given only a MAC address.
Task
Interface with one (or numer... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Straddling_checkerboard | Straddling checkerboard | Task
Implement functions to encrypt and decrypt a message using the straddling checkerboard method. The checkerboard should take a 28 character alphabet (A-Z plus a full stop and an escape character) and two different numbers representing the blanks in the first row. The output will be a series of decimal digits.
Num... | #PHP | PHP | $key2val = ["A"=>"30", "B"=>"31", "C"=>"32", "D"=>"33", "E"=>"5", "F"=>"34", "G"=>"35",
"H"=>"0", "I"=>"36", "J"=>"37", "K"=>"38", "L"=>"2", "M"=>"4", "."=>"78", "N"=>"39",
"/"=>"79", "O"=>"1", "0"=>"790", "P"=>"70", "1"=>"791", "Q"=>"71", "2"=>"792",
"R"=>"8", "3"=>"793", "S"=>"6", "4"=>"794", ... | Give a code snippet in #PHP
Task
Implement functions to encrypt and decrypt a message using the straddling checkerboard method. The checkerboard should take a 28 character alphabet (A-Z plus a full stop and an escape character) and two different numbers representing the blanks in the first row. The output will be a s... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Associative_array/Creation | Associative array/Creation | Task
The goal is to create an associative array (also known as a dictionary, map, or hash).
Related tasks:
Associative arrays/Iteration
Hash from two arrays
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element ins... | #J | J | coclass 'assocArray'
encode=: 'z', (a.{~;48 65 97(+ i.)&.>10 26 26) {~ 62x #.inv 256x #. a.&i.
get=: ".@encode
has=: 0 <: nc@<@encode
set=:4 :'(encode x)=:y' | Give a code snippet in #J
Task
The goal is to create an associative array (also known as a dictionary, map, or hash).
Related tasks:
Associative arrays/Iteration
Hash from two arrays
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Elem... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Averages/Median | Averages/Median | Task[edit]
Write a program to find the median value of a vector of floating-point numbers.
The program need not handle the case where the vector is empty, but must handle the case where there are an even number of elements. In that case, return the average of the two middle values.
There are several approaches ... | #Groovy | Groovy | def median(Iterable col) {
def s = col as SortedSet
if (s == null) return null
if (s.empty) return 0
def n = s.size()
def m = n.intdiv(2)
def l = s.collect { it }
n%2 == 1 ? l[m] : (l[m] + l[m-1])/2
} | Give a code snippet in #Groovy
Task[edit]
Write a program to find the median value of a vector of floating-point numbers.
The program need not handle the case where the vector is empty, but must handle the case where there are an even number of elements. In that case, return the average of the two middle values... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Increment_a_numerical_string | Increment a numerical string | Task
Increment a numerical string.
| #Retro | Retro | '123 s:to-number n:inc n:to-string | Give a code snippet in #Retro
Task
Increment a numerical string.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Emirp_primes | Emirp primes | An emirp (prime spelled backwards) are primes that when reversed (in their decimal representation) are a different prime.
(This rules out palindromic primes.)
Task
show the first twenty emirps
show all emirps between 7,700 and 8,000
show the 10,000th emirp
In each list, the numbe... | #D | D | bool isEmirp(uint n) pure nothrow @nogc {
bool isPrime(in uint n) pure nothrow @nogc {
if (n == 2 || n == 3)
return true;
else if (n < 2 || n % 2 == 0 || n % 3 == 0)
return false;
for (uint div = 5, inc = 2; div ^^ 2 <= n;
div += inc, inc = 6 - inc)
... | Give a code snippet in #D
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 emir... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Ruth-Aaron_numbers | Ruth-Aaron numbers | A Ruth–Aaron pair consists of two consecutive integers (e.g., 714 and 715) for which the sums of the prime divisors of each integer are equal. So called because 714 is Babe Ruth's lifetime home run record; Hank Aaron's 715th home run broke this record and 714 and 715 have the same prime divisor sum.
A Ruth–Aaron tri... | #Phix | Phix | with javascript_semantics
procedure ruth_aaron(bool d, integer n=30, l=2, i=1)
string fd = iff(d?"divisors":"factors"),
ns = iff(n=1?"":sprintf(" %d",n)),
ss = iff(n=1?"":"s"),
nt = iff(l=2?"number":"triple")
printf(1,"First%s Ruth-Aaron %s%s (%s):\n",{ns,nt,ss,fd})
integer ... | Give a code snippet in #Phix
A Ruth–Aaron pair consists of two consecutive integers (e.g., 714 and 715) for which the sums of the prime divisors of each integer are equal. So called because 714 is Babe Ruth's lifetime home run record; Hank Aaron's 715th home run broke this record and 714 and 715 have the same prime di... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Subtractive_generator | Subtractive generator | A subtractive generator calculates a sequence of random numbers, where each number is congruent to the subtraction of two previous numbers from the sequence.
The formula is
r
n
=
r
(
n
−
i
)
−
r
(
n
−
j
)
(
mod
m
)
{\displaystyle r_{n}=r_{(n-i)}-r_{(n-j)}{\pmod {m}}}
for some fixed values of... | #Kotlin | Kotlin | // version 1.1.51
const val MOD = 1_000_000_000
val state = IntArray(55)
var si = 0
var sj = 0
fun subrandSeed(p: Int) {
var p1 = p
var p2 = 1
state[0] = p1 % MOD
var j = 21
for (i in 1..54) {
if (j >=55) j -= 55
state[j] = p2
p2 = p1 - p2
if (p2 < 0) p2 ... | Give a code snippet in #Kotlin
A subtractive generator calculates a sequence of random numbers, where each number is congruent to the subtraction of two previous numbers from the sequence.
The formula is
r
n
=
r
(
n
−
i
)
−
r
(
n
−
j
)
(
mod
m
)
{\displaystyle r_{n}=r_{(n-i)}-r_{(n-j)}{\pmod ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Terminal_control/Inverse_video | Terminal control/Inverse video | Task
Display a word in inverse video (or reverse video) followed by a word in normal video.
| #Raku | Raku | say "normal";
run "tput", "rev";
say "reversed";
run "tput", "sgr0";
say "normal"; | Give a code snippet in #Raku
Task
Display a word in inverse video (or reverse video) followed by a word in normal video.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Damm_algorithm | Damm algorithm | The Damm algorithm is a checksum algorithm which detects all single digit errors and adjacent transposition errors.
The algorithm is named after H. Michael Damm.
Task
Verify the checksum, stored as last digit of an input.
| #PL.2FM | PL/M | 100H:
/* DAMM CHECKSUM FOR DECIMAL NUMBER IN GIVEN STRING */
CHECK$DAMM: PROCEDURE (PTR) BYTE;
DECLARE PTR ADDRESS, CH BASED PTR BYTE;
DECLARE DAMM DATA
( 0,3,1,7,5,9,8,6,4,2,
7,0,9,2,1,5,4,8,6,3,
4,2,0,6,8,7,1,3,5,9,
1,7,5,0,9,8,3,4,2,6,
6,1,2,3,0,4,5,9,7,8,
... | Give a code snippet in #PL.2FM
The Damm algorithm is a checksum algorithm which detects all single digit errors and adjacent transposition errors.
The algorithm is named after H. Michael Damm.
Task
Verify the checksum, stored as last digit of an input.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Anagrams/Deranged_anagrams | Anagrams/Deranged anagrams | Two or more words are said to be anagrams if they have the same characters, but in a different order.
By analogy with derangements we define a deranged anagram as two words with the same characters, but in which the same character does not appear in the same position in both words.
Task[edit]
Use the word list at uni... | #Common_Lisp | Common Lisp | (defun read-words (file)
(with-open-file (stream file)
(loop with w = "" while w collect (setf w (read-line stream nil)))))
(defun deranged (a b)
(loop for ac across a for bc across b always (char/= ac bc)))
(defun longest-deranged (file)
(let ((h (make-hash-table :test #'equal))
(wordlist (sort (read-wo... | Give a code snippet in #Common_Lisp
Two or more words are said to be anagrams if they have the same characters, but in a different order.
By analogy with derangements we define a deranged anagram as two words with the same characters, but in which the same character does not appear in the same position in both words.... | 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 ... | #Fortran | Fortran | program lcstest
use iso_varying_string
implicit none
type(varying_string) :: s1, s2
s1 = "thisisatest"
s2 = "testing123testing"
print *, char(lcs(s1, s2))
s1 = "1234"
s2 = "1224533324"
print *, char(lcs(s1, s2))
contains
recursive function lcs(a, b) result(l)
type(varying_string) :: l
... | Give a code snippet in #Fortran
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 str... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Accumulator_factory | Accumulator factory | A problem posed by Paul Graham is that of creating a function that takes a single (numeric) argument and which returns another function that is an accumulator. The returned accumulator function in turn also takes a single numeric argument, and returns the sum of all the numeric values passed in so far to that accumulat... | #Wart | Wart | def (accumulator n)
(fn() ++n) | Give a code snippet in #Wart
A problem posed by Paul Graham is that of creating a function that takes a single (numeric) argument and which returns another function that is an accumulator. The returned accumulator function in turn also takes a single numeric argument, and returns the sum of all the numeric values pass... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Summarize_and_say_sequence | Summarize and say sequence | There are several ways to generate a self-referential sequence. One very common one (the Look-and-say sequence) is to start with a positive integer, then generate the next term by concatenating enumerated groups of adjacent alike digits:
0, 10, 1110, 3110, 132110, 1113122110, 311311222110 ...
The terms generat... | #REXX | REXX | /*REXX pgm generates a self─referential sequence and displays sequences with max length.*/
parse arg LO HI . /*obtain optional arguments from the CL*/
if LO=='' | LO=="," then LO= 1 /*Not specified? Then use the default.*/
if HI=='' | HI=="," then HI=1000000 - 1 ... | Give a code snippet in #REXX
There are several ways to generate a self-referential sequence. One very common one (the Look-and-say sequence) is to start with a positive integer, then generate the next term by concatenating enumerated groups of adjacent alike digits:
0, 10, 1110, 3110, 132110, 1113122110, 31131... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Function_definition | Function definition | A function is a body of code that returns a value.
The value returned may depend on arguments provided to the function.
Task
Write a definition of a function called "multiply" that takes two arguments and returns their product.
(Argument types should be chosen so as not to distract from showing how functions are ... | #Pop11 | Pop11 | define multiply(a, b);
a * b
enddefine; | Give a code snippet in #Pop11
A function is a body of code that returns a value.
The value returned may depend on arguments provided to the function.
Task
Write a definition of a function called "multiply" that takes two arguments and returns their product.
(Argument types should be chosen so as not to distract ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #Oberon-2 | Oberon-2 |
VAR
a,b,c: BOOLEAN;
...
a := TRUE;
b := FALSE;
c := 1 > 2;
| Give a code snippet in #Oberon-2
Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| christopher/rosetta-code | |
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... | #Python | Python |
from collections import namedtuple
from hashlib import sha256
from math import ceil, log
from random import randint
from typing import NamedTuple
# Bitcoin ECDSA curve
secp256k1_data = dict(
p=0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F, # Field characteristic
a=0x0, # Curve param a... | Give a code snippet in #Python
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,
whi... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Read_a_file_character_by_character/UTF8 | Read a file character by character/UTF8 | Task
Read a file one character at a time, as opposed to reading the entire file at once.
The solution may be implemented as a procedure, which returns the next character in the file on each consecutive call (returning EOF when the end of the file is reached).
The procedure should support the reading of files contain... | #NetRexx | NetRexx | /* NetRexx */
options replace format comments java crossref symbols nobinary
numeric digits 20
runSample(arg)
return
-- ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
method readCharacters(fName) public static binary returns String
slurped = String('')
slrp = StringBuilder()
fr ... | Give a code snippet in #NetRexx
Task
Read a file one character at a time, as opposed to reading the entire file at once.
The solution may be implemented as a procedure, which returns the next character in the file on each consecutive call (returning EOF when the end of the file is reached).
The procedure should sup... | christopher/rosetta-code | |
http://rosettacode.org/wiki/A%2BB | A+B | A+B ─── a classic problem in programming contests, it's given so contestants can gain familiarity with the online judging system being used.
Task
Given two integers, A and B.
Their sum needs to be calculated.
Input data
Two integers are written in the input stream, separated by space(s):
(
−
1000
≤... | #Free_Pascal | Free Pascal | program SUMA;
uses
SysUtils;
var
s1, s2:integer;
begin
ReadLn(s1);
Readln(s2);
WriteLn(IntToStr(s1 + s2));
end.
| Give a code snippet in #Free_Pascal
A+B ─── a classic problem in programming contests, it's given so contestants can gain familiarity with the online judging system being used.
Task
Given two integers, A and B.
Their sum needs to be calculated.
Input data
Two integers are written in the input stream, se... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Zero_to_the_zero_power | Zero to the zero power | Some computer programming languages are not exactly consistent (with other computer programming languages)
when raising zero to the zeroth power: 00
Task
Show the results of raising zero to the zeroth power.
If your computer language objects to 0**0 or 0^0 at compile time, ... | #Lua | Lua | print(0^0) | Give a code snippet in #Lua
Some computer programming languages are not exactly consistent (with other computer programming languages)
when raising zero to the zeroth power: 00
Task
Show the results of raising zero to the zeroth power.
If your computer language objects to 0**0 or ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/String_matching | String matching |
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 |... | #Aime | Aime | text t;
data b;
b = "Bangkok";
t = "Bang";
o_form("starts with, embeds, ends with \"~\": ~, ~, ~\n", t, b.seek(t) == 0,
b.seek(t) != -1,
b.seek(t) != -1 && b.seek(t) + ~t == ~b);
t = "ok";
o_form("starts with, embeds, ends with \"~\": ~, ~, ~\n", t, b.seek(t) == 0,
b.seek(t) != -1,
... | Give a code snippet in #Aime
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
C... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Call_a_function_in_a_shared_library | Call a function in a shared library | Show how to call a function in a shared library (without dynamically linking to it at compile-time). In particular, show how to call the shared library function if the library is available, otherwise use an internal equivalent function.
This is a special case of calling a foreign language function where the focus is c... | #Java | Java | /* TrySort.java */
import java.util.Collections;
import java.util.Random;
public class TrySort {
static boolean useC;
static {
try {
System.loadLibrary("TrySort");
useC = true;
} catch(UnsatisfiedLinkError e) {
useC = false;
}
}
static native void sortInC(int[] ary);
static... | Give a code snippet in #Java
Show how to call a function in a shared library (without dynamically linking to it at compile-time). In particular, show how to call the shared library function if the library is available, otherwise use an internal equivalent function.
This is a special case of calling a foreign language... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Call_an_object_method | Call an object method | In object-oriented programming a method is a function associated with a particular class or object. In most forms of object oriented implementations methods can be static, associated with the class itself; or instance, associated with an instance of a class.
Show how to call a static or class method, and an instance m... | #LFE | LFE | (defmodule aquarium
(export all))
(defun fish-class (species)
"
This is the constructor that will be used most often, only requiring that
one pass a 'species' string.
When the children are not defined, simply use an empty list.
"
(fish-class species ()))
(defun fish-class (species children)
"
Thi... | Give a code snippet in #LFE
In object-oriented programming a method is a function associated with a particular class or object. In most forms of object oriented implementations methods can be static, associated with the class itself; or instance, associated with an instance of a class.
Show how to call a static or cl... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Hello_world/Graphical | Hello world/Graphical |
Task
Display the string Goodbye, World! on a GUI object (alert box, plain window, text area, etc.).
Related task
Hello world/Text
| #Neko | Neko | /*
Tectonics:
gcc -shared -fPIC -o nekoagar.ndll nekoagar.c `agar-config --cflags --libs`
*/
/* Neko primitives for libAgar http://www.libagar.org */
#include <stdio.h>
#include <neko.h>
#include <agar/core.h>
#include <agar/gui.h>
#define val_widget(v) ((AG_Widget *)val_data(v))
DEFINE_KIND(k_agar_widg... | Give a code snippet in #Neko
Task
Display the string Goodbye, World! on a GUI object (alert box, plain window, text area, etc.).
Related task
Hello world/Text
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #MontiLang | MontiLang |
/# This is a comment #/
/#
comments can span multiple lines
nested comments are not supported #/
| Give a code snippet in #MontiLang
Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Append_a_record_to_the_end_of_a_text_file | Append a record to the end of a text file | Many systems offer the ability to open a file for writing, such that any data written will be appended to the end of the file. Further, the file operations will always adjust the position pointer to guarantee the end of the file, even in a multitasking environment.
This feature is most useful in the case of log files,... | #PHP | PHP | <?php
$filename = '/tmp/passwd';
$data = array(
'account:password:UID:GID:fullname,office,extension,homephone,email:directory:shell' . PHP_EOL,
'jsmith:x:1001:1000:Joe Smith,Room 1007,(234)555-8917,(234)555-0077,jsmith@rosettacode.org:/home/jsmith:/bin/bash' . PHP_EOL,
'jdoe:x:1002:1000:Jane Doe,Room 10... | Give a code snippet in #PHP
Many systems offer the ability to open a file for writing, such that any data written will be appended to the end of the file. Further, the file operations will always adjust the position pointer to guarantee the end of the file, even in a multitasking environment.
This feature is most use... | christopher/rosetta-code | |
http://rosettacode.org/wiki/100_prisoners | 100 prisoners |
The Problem
100 prisoners are individually numbered 1 to 100
A room having a cupboard of 100 opaque drawers numbered 1 to 100, that cannot be seen from outside.
Cards numbered 1 to 100 are placed randomly, one to a drawer, and the drawers all closed; at the start.
Prisoners start outside the room
They can decid... | #Swift | Swift | import Foundation
struct PrisonersGame {
let strategy: Strategy
let numPrisoners: Int
let drawers: [Int]
init(numPrisoners: Int, strategy: Strategy) {
self.numPrisoners = numPrisoners
self.strategy = strategy
self.drawers = (1...numPrisoners).shuffled()
}
@discardableResult
func play() -... | Give a code snippet in #Swift
The Problem
100 prisoners are individually numbered 1 to 100
A room having a cupboard of 100 opaque drawers numbered 1 to 100, that cannot be seen from outside.
Cards numbered 1 to 100 are placed randomly, one to a drawer, and the drawers all closed; at the start.
Prisoners start o... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Priority_queue | Priority queue | A priority queue is somewhat similar to a queue, with an important distinction: each item is added to a priority queue with a priority level, and will be later removed from the queue with the highest priority element first. That is, the items are (conceptually) stored in the queue in priority order instead of in insert... | #Batch_File | Batch File |
@echo off
setlocal enabledelayedexpansion
call :push 10 "item ten"
call :push 2 "item two"
call :push 100 "item one hundred"
call :push 5 "item five"
call :pop & echo !order! !item!
call :pop & echo !order! !item!
call :pop & echo !order! !item!
call :pop & echo !order! !item!
call :pop & echo !order! !item!... | Give a code snippet in #Batch_File
A priority queue is somewhat similar to a queue, with an important distinction: each item is added to a priority queue with a priority level, and will be later removed from the queue with the highest priority element first. That is, the items are (conceptually) stored in the queue in... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Dutch_national_flag_problem | Dutch national flag problem |
The Dutch national flag is composed of three coloured bands in the order:
red (top)
then white, and
lastly blue (at the bottom).
The problem posed by Edsger Dijkstra is:
Given a number of red, blue and white balls in random order, arrange them in the order of the colours in the Dutch national fla... | #PicoLisp | PicoLisp | (def 'Colors
(list
(def 'RED 1)
(def 'WHITE 2)
(def 'BLUE 3) ) )
(let (L (make (do 9 (link (get Colors (rand 1 3))))) S (by val sort L))
(prin "Original balls ")
(print L)
(prinl (unless (= L S) " not sorted"))
(prin "Sorted balls ")
(print S)
(prinl " are sorted") ) | Give a code snippet in #PicoLisp
The Dutch national flag is composed of three coloured bands in the order:
red (top)
then white, and
lastly blue (at the bottom).
The problem posed by Edsger Dijkstra is:
Given a number of red, blue and white balls in random order, arrange them in the order of the... | 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
... | #zkl | zkl | fcn cocktailSort(a){
swapped,begin,end:=False,-1,a.len() - 2;
do{
swapped,begin=False,begin + 1;
foreach i in ([begin .. end]){
if(a[i]>a[i+1]){ a.swap(i,i+1); swapped=True; }
}
if(not swapped) break;
swapped,end=False,end - 1;
foreach i in ([end..begin,-1]){
if(a[i]... | Give a code snippet in #zkl
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/Word_frequency | Word frequency | Task
Given a text file and an integer n, print/display the n most
common words in the file (and the number of their occurrences) in decreasing frequency.
For the purposes of this task:
A word is a sequence of one or more contiguous letters.
You are free to define what a letter is.
Undersc... | #Ada | Ada | with Ada.Command_Line;
with Ada.Text_IO;
with Ada.Integer_Text_IO;
with Ada.Strings.Maps;
with Ada.Strings.Fixed;
with Ada.Characters.Handling;
with Ada.Containers.Indefinite_Ordered_Maps;
with Ada.Containers.Indefinite_Ordered_Sets;
with Ada.Containers.Ordered_Maps;
procedure Word_Frequency is
package TIO rename... | Give a code snippet in #Ada
Task
Given a text file and an integer n, print/display the n most
common words in the file (and the number of their occurrences) in decreasing frequency.
For the purposes of this task:
A word is a sequence of one or more contiguous letters.
You are free to define what... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Combinations | Combinations | Task
Given non-negative integers m and n, generate all size m combinations of the integers from 0 (zero) to n-1 in sorted order (each combination is sorted and the entire table is sorted).
Example
3 comb 5 is:
0 1 2
0 1 3
0 1 4
0 2 3
0 2 4
0 3 4
1 2 3
1 2 4
1 3 4
2 3 4
... | #EchoLisp | EchoLisp |
;;
;; using the native (combinations) function
(lib 'list)
(combinations (iota 5) 3)
→ ((0 1 2) (0 1 3) (0 1 4) (0 2 3) (0 2 4) (0 3 4) (1 2 3) (1 2 4) (1 3 4) (2 3 4))
;;
;; using an iterator
;;
(lib 'sequences)
(take (combinator (iota 5) 3) #:all)
→ ((0 1 2) (0 1 3) (0 1 4) (0 2 3) (0 2 4) (0 3 4) (1 2 3) (1 2 4) (... | Give a code snippet in #EchoLisp
Task
Given non-negative integers m and n, generate all size m combinations of the integers from 0 (zero) to n-1 in sorted order (each combination is sorted and the entire table is sorted).
Example
3 comb 5 is:
0 1 2
0 1 3
0 1 4
0 2 3
0 ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Polymorphism | Polymorphism | Task
Create two classes Point(x,y) and Circle(x,y,r) with a polymorphic function print, accessors for (x,y,r), copy constructor, assignment and destructor and every possible default constructors
| #R | R | setClass("point",
representation(
x="numeric",
y="numeric"),
prototype(
x=0,
y=0))
# Instantiate class with some arguments
p1 <- new("point", x=3)
# Access some values
p1@x # 3
# Define a print method
setMethod("print", signature("point"),
function(x, ...)
{
cat("This i... | Give a code snippet in #R
Task
Create two classes Point(x,y) and Circle(x,y,r) with a polymorphic function print, accessors for (x,y,r), copy constructor, assignment and destructor and every possible default constructors
| christopher/rosetta-code | |
http://rosettacode.org/wiki/File_input/output | File input/output | File input/output is part of Short Circuit's Console Program Basics selection.
Task
Create a file called "output.txt", and place in it the contents of the file "input.txt", via an intermediate variable.
In other words, your program will demonstrate:
how to read from a file into a variable
how to write ... | #ARM_Assembly | ARM Assembly |
/* ARM assembly Raspberry PI */
/* program readwrtfile.s */
/*********************************************/
/*constantes */
/********************************************/
.equ STDOUT, 1 @ Linux output console
.equ EXIT, 1 @ Linux syscall
.equ READ, 3
.equ WRITE, 4
.... | Give a code snippet in #ARM_Assembly
File input/output is part of Short Circuit's Console Program Basics selection.
Task
Create a file called "output.txt", and place in it the contents of the file "input.txt", via an intermediate variable.
In other words, your program will demonstrate:
how to read from a... | 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.
| #Octave | Octave | function e = f(x, y)
e = x^2 + exp(-1/(y+1));
endfunction
% f([2,3], [1,4]) gives and error, but
arrayfun(@f, [2, 3], [1,4])
% works | Give a code snippet in #Octave
Task
Take a combined set of elements and apply a function to each element.
| christopher/rosetta-code | |
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 ... | #Metafont | Metafont | vardef halve(expr x) = floor(x/2) enddef;
vardef double(expr x) = x*2 enddef;
vardef iseven(expr x) = if (x mod 2) = 0: true else: false fi enddef;
primarydef a ethiopicmult b =
begingroup
save r_, plier_, plicand_;
plier_ := a; plicand_ := b;
r_ := 0;
forever: exitif plier_ < 1;
if not iseven... | Give a code snippet in #Metafont
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, an... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Temperature_conversion | Temperature conversion | There are quite a number of temperature scales. For this task we will concentrate on four of the perhaps best-known ones:
Kelvin, Celsius, Fahrenheit, and Rankine.
The Celsius and Kelvin scales have the same magnitude, but different null points.
0 degrees Celsius corresponds to 273.15 kelvin.
0 kelvin is absolute z... | #Ceylon | Ceylon | shared void run() {
void printKelvinConversions(Float kelvin) {
value celsius = kelvin - 273.15;
value rankine = kelvin * 9.0 / 5.0;
value fahrenheit = rankine - 459.67;
print("Kelvin: ``formatFloat(kelvin, 2, 2)``
Celsius: ``formatFloat(celsius, 2, 2)``
... | Give a code snippet in #Ceylon
There are quite a number of temperature scales. For this task we will concentrate on four of the perhaps best-known ones:
Kelvin, Celsius, Fahrenheit, and Rankine.
The Celsius and Kelvin scales have the same magnitude, but different null points.
0 degrees Celsius corresponds to 273.15... | 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.... | #ColdFusion | ColdFusion |
<Cfset theString = 'METHINKS IT IS LIKE A WEASEL'>
<cfparam name="parent" default="">
<Cfset theAlphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ ">
<Cfset fitness = 0>
<Cfset children = 3>
<Cfset counter = 0>
<Cfloop from="1" to="#children#" index="child">
<Cfparam name="child#child#" default="">
<Cfparam name="fitness#c... | Give a code snippet in #ColdFusion
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’ o... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Reverse_a_string | Reverse a string | Task
Take a string and reverse it.
For example, "asdf" becomes "fdsa".
Extra credit
Preserve Unicode combining characters.
For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa".
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
... | #MUMPS | MUMPS | REVERSE
;Take in a string and reverse it using the built in function $REVERSE
NEW S
READ:30 "Enter a string: ",S
WRITE !,$REVERSE(S)
QUIT | Give a code snippet in #MUMPS
Task
Take a string and reverse it.
For example, "asdf" becomes "fdsa".
Extra credit
Preserve Unicode combining characters.
For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa".
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Strip_comments_from_a_string | Strip comments from a string | Strip comments from a string
You are encouraged to solve this task according to the task description, using any language you may know.
The task is to remove text that follow any of a set of comment markers, (in these examples either a hash or a semicolon) from a string or input line.
Whitespace debacle: There is s... | #Rust | Rust | fn strip_comment<'a>(input: &'a str, markers: &[char]) -> &'a str {
input
.find(markers)
.map(|idx| &input[..idx])
.unwrap_or(input)
.trim()
}
fn main() {
println!("{:?}", strip_comment("apples, pears # and bananas", &['#', ';']));
println!("{:?}", strip_comment("apples, pe... | Give a code snippet in #Rust
Strip comments from a string
You are encouraged to solve this task according to the task description, using any language you may know.
The task is to remove text that follow any of a set of comment markers, (in these examples either a hash or a semicolon) from a string or input line.
Wh... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/For | Loops/For | “For” loops are used to make some block of code be iterated a number of times, setting a variable or parameter to a monotonically increasing integer value for each execution of the block of code.
Common extensions of this allow other counting patterns or iterating over abstract structures other than the integers.
... | #BCPL | BCPL | get "libhdr"
let start() be
for i = 1 to 5
$( for j = 1 to i do wrch('**')
wrch('*N')
$) | Give a code snippet in #BCPL
“For” loops are used to make some block of code be iterated a number of times, setting a variable or parameter to a monotonically increasing integer value for each execution of the block of code.
Common extensions of this allow other counting patterns or iterating over abstract structur... | 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... | #MATLAB_.2F_Octave | MATLAB / Octave | while true
fprintf('SPAM\n')
end | Give a code snippet in #MATLAB_.2F_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/For... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Multiple_distinct_objects | Multiple distinct objects | Create a sequence (array, list, whatever) consisting of n distinct, initialized items of the same type. n should be determined at runtime.
By distinct we mean that if they are mutable, changes to one do not affect all others; if there is an appropriate equality operator they are considered unequal; etc. The code need ... | #Ruby | Ruby | [Foo.new] * n # here Foo.new can be any expression that returns a new object
Array.new(n, Foo.new) | Give a code snippet in #Ruby
Create a sequence (array, list, whatever) consisting of n distinct, initialized items of the same type. n should be determined at runtime.
By distinct we mean that if they are mutable, changes to one do not affect all others; if there is an appropriate equality operator they are considere... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Align_columns | Align columns | Given a text file of many lines, where fields within a line
are delineated by a single 'dollar' character, write a program
that aligns each column of fields by ensuring that words in each
column are separated by at least one space.
Further, allow for each word in a column to be either left
justified, right justified, o... | #HicEst | HicEst |
CHARACTER Fnam = "\HicEst\Rosetta\Align columns.txt"
OPEN(FIle=Fnam, Format="12$", LENgth=rows)
! call the DLG function in MatrixExplorer mode:
DLG(Edit=Fnam, Format='12A10') ! left adjusted, 12 columns, 10 spaces each
! or the standard way:
CALL Align( "LLLLLLLLLLL ", Fnam, rows) ! left align
CAL... | Give a code snippet in #HicEst
Given a text file of many lines, where fields within a line
are delineated by a single 'dollar' character, write a program
that aligns each column of fields by ensuring that words in each
column are separated by at least one space.
Further, allow for each word in a column to be either le... | 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.
... | #Go | Go | package main
import (
"fmt"
"path/filepath"
)
func main() {
fmt.Println(filepath.Glob("*.go"))
} | Give a code snippet in #Go
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... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sort_a_list_of_object_identifiers | Sort a list of object identifiers |
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
... | #Java | Java |
package com.rosettacode;
import java.util.Comparator;
import java.util.stream.Stream;
public class OIDListSorting {
public static void main(String[] args) {
final String dot = "\\.";
final Comparator<String> oids_comparator = (o1, o2) -> {
final String[] o1Numbers = o1.split(... | 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/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 ... | #Ol | Ol |
(define (dot-product a b)
(apply + (map * a b)))
(print (dot-product '(1 3 -5) '(4 -2 -1)))
; ==> 3
| Give a code snippet in #Ol
Task
Create a function/use an in-built function, to compute the dot product, also known as the scalar product of two vectors.
If possible, make the vectors of arbitrary length.
As an example, compute the dot product of the vectors:
[1, 3, -5] and
[4, -2, -1] ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/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 ... | #ALGOL_68 | ALGOL 68 | PROC halve = (REF INT x)VOID: x := ABS(BIN x SHR 1);
PROC doublit = (REF INT x)VOID: x := ABS(BIN x SHL 1);
PROC iseven = (#CONST# INT x)BOOL: NOT ODD x;
PROC ethiopian = (INT in plier,
INT in plicand, #CONST# BOOL tutor)INT:
(
INT plier := in plier, plicand := in plicand;
INT result:=0;
IF tuto... | Give a code snippet in #ALGOL_68
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, an... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Almkvist-Giullera_formula_for_pi | Almkvist-Giullera formula for pi | The Almkvist-Giullera formula for calculating 1/π2 is based on the Calabi-Yau
differential equations of order 4 and 5, which were originally used to describe certain manifolds
in string theory.
The formula is:
1/π2 = (25/3) ∑0∞ ((6n)! / (n!6))(532n2 + 126n + 9) / 10002n+1
This formula can be used to calcul... | #Quackery | Quackery | [ $ "bigrat.qky" loadfile ] now!
[ 1 swap times [ i^ 1+ * ] ] is ! ( n --> n )
[ dup dup 2 ** 532 *
over 126 * + 9 +
swap 6 * ! * 32 *
swap ! 6 ** 3 * / ] is intterm ( n --> n )
[ dup intterm
10 rot 6 * 3 + **
reduce ] is vterm ( n --> n/d )
1... | Give a code snippet in #Quackery
The Almkvist-Giullera formula for calculating 1/π2 is based on the Calabi-Yau
differential equations of order 4 and 5, which were originally used to describe certain manifolds
in string theory.
The formula is:
1/π2 = (25/3) ∑0∞ ((6n)! / (n!6))(532n2 + 126n + 9) / 10002n+1
... | 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... | #C.23 | C# | using System;
namespace BullsnCows
{
class Program
{
static void Main(string[] args)
{
int[] nums = new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
KnuthShuffle<int>(ref nums);
int[] chosenNum = new int[4];
Array.Copy(nums, chosenNum, 4);
... | Give a code snippet in #C.23
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 g... | 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... | #Rust | Rust | fn encode(s: &str) -> String {
s.chars()
// wrap all values in Option::Some
.map(Some)
// add an Option::None onto the iterator to clean the pipeline at the end
.chain(std::iter::once(None))
.scan((0usize, '\0'), |(n, c), elem| match elem {
Some(elem) if *n == 0 |... | Give a code snippet in #Rust
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 funct... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sorting_algorithms/Pancake_sort | Sorting algorithms/Pancake 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
... | #AppleScript | AppleScript | on pancake_sort(aList)
script o
property lst : aList
property len : (count my lst)
on flip(n)
if (n < len) then
set my lst to (reverse of items 1 thru n of my lst) & (items (n + 1) thru len of my lst)
else
set my lst to reverse of my ... | Give a code snippet in #AppleScript
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Qu... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Simple_windowed_application | Simple windowed application | Task
Create a window that has:
a label that says "There have been no clicks yet"
a button that says "click me"
Upon clicking the button with the mouse, the label should change and show the number of times the button has been clicked.
| #Euphoria | Euphoria | include EuWinGUI.ew
Window("EuWinGUI - Simple windowed application",100,100,360,100)
constant Button1 = Control(Button,"Click me",250,20,80,25)
constant Label1 = Control(Label,"There have been no clicks yet",10,25,200,18)
integer clicks
clicks = 0
-- Event loop
while 1 do
WaitEvent()
if EventOwner = Butto... | Give a code snippet in #Euphoria
Task
Create a window that has:
a label that says "There have been no clicks yet"
a button that says "click me"
Upon clicking the button with the mouse, the label should change and show the number of times the button has been clicked.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/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... | #ooRexx | ooRexx | doors = .array~new(100) -- array containing all of the doors
do i = 1 to doors~size -- initialize with a collection of closed doors
doors[i] = .door~new(i)
end
do inc = 1 to doors~size
do d = inc to doors~size by inc
doors[d]~toggle
end
end
say "The open doors after 100 passes:"
do door over doors
... | Give a code snippet in #ooRexx
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/File_input/output | File input/output | File input/output is part of Short Circuit's Console Program Basics selection.
Task
Create a file called "output.txt", and place in it the contents of the file "input.txt", via an intermediate variable.
In other words, your program will demonstrate:
how to read from a file into a variable
how to write ... | #Oforth | Oforth | : fcopy(in, out)
| f g |
File newMode(in, File.BINARY) dup open(File.READ) ->f
File newMode(out, File.BINARY) dup open(File.WRITE) ->g
while(f >> dup notNull) [ g addChar ] drop
f close g close ; | Give a code snippet in #Oforth
File input/output is part of Short Circuit's Console Program Basics selection.
Task
Create a file called "output.txt", and place in it the contents of the file "input.txt", via an intermediate variable.
In other words, your program will demonstrate:
how to read from a file ... | christopher/rosetta-code |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.