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/Lah_numbers | Lah numbers | Lah numbers, sometimes referred to as Stirling numbers of the third kind, are coefficients of polynomial expansions expressing rising factorials in terms of falling factorials.
Unsigned Lah numbers count the number of ways a set of n elements can be partitioned into k non-empty linearly ordered subsets.
Lah numbers a... | #Nim | Nim | import math, strutils
import bignum
func lah[T: int | Int](n, k: T; signed = false): T =
if n == 0 or k == 0 or k > n: return when T is int: 0 else: newInt(0)
if n == k: return when T is int: 1 else: newInt(1)
if k == 1: return fac(n)
result = binom(n, k) * binom(n - 1, k - 1) * fac(n - k)
if signed and (n ... | Give a code snippet in #Nim
Lah numbers, sometimes referred to as Stirling numbers of the third kind, are coefficients of polynomial expansions expressing rising factorials in terms of falling factorials.
Unsigned Lah numbers count the number of ways a set of n elements can be partitioned into k non-empty linearly or... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Pentagram | Pentagram |
A pentagram is a star polygon, consisting of a central pentagon of which each side forms the base of an isosceles triangle. The vertex of each triangle, a point of the star, is 36 degrees.
Task
Draw (or print) a regular pentagram, in any orientation. Use a different color (or token) for stroke and fill, and backg... | #ooRexx | ooRexx | /* REXX ***************************************************************
* Create a BMP file showing a pentagram
**********************************************************************/
pentagram='pentagram.bmp'
'erase' pentagram
s='424d4600000000000000360000002800000038000000280000000100180000000000'X
s=s'10000000000000... | Give a code snippet in #ooRexx
A pentagram is a star polygon, consisting of a central pentagon of which each side forms the base of an isosceles triangle. The vertex of each triangle, a point of the star, is 36 degrees.
Task
Draw (or print) a regular pentagram, in any orientation. Use a different color (or token... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Order_two_numerical_lists | Order two numerical lists | sorting
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
She... | #Picat | Picat | go =>
Tests = [
[[1,2,3], [1,2,3]],
[[1,2,3], [1,2,3,4]],
[[1,2,2], [1,2,3]],
[[1,2,4], [1,2,3]],
[1..10 , 1..8],
[[] , []],
[[] , [1]],
[[1] , [] ],
[[-1,2,3,6,5],[-1,2,3,5,6]],
[[-1,2,3,-5,6],[-1,2,3,-6,5]]
],
foreach([L1,L2] in Tests)
printf("%... | Give a code snippet in #Picat
sorting
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 |
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Remove_duplicate_elements | Remove duplicate elements |
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
... | #Rust | Rust | use std::collections::HashSet;
use std::hash::Hash;
fn remove_duplicate_elements_hashing<T: Hash + Eq>(elements: &mut Vec<T>) {
let set: HashSet<_> = elements.drain(..).collect();
elements.extend(set.into_iter());
}
fn remove_duplicate_elements_sorting<T: Ord>(elements: &mut Vec<T>) {
elements.sort_unst... | Give a code snippet in #Rust
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/Five_weekends | Five weekends | The month of October in 2010 has five Fridays, five Saturdays, and five Sundays.
Task
Write a program to show all months that have this same characteristic of five full weekends from the year 1900 through 2100 (Gregorian calendar).
Show the number of months with this property (there should be 201).
Show at leas... | #Racket | Racket |
#lang racket
(require srfi/19)
(define long-months '(1 3 5 7 8 10 12))
(define days #(sun mon tue wed thu fri sat))
(define (week-day date)
(vector-ref days (date-week-day date)))
(define (five-weekends-a-month start end)
(for*/list ([year (in-range start (+ end 1))]
[month long-months]
... | Give a code snippet in #Racket
The month of October in 2010 has five Fridays, five Saturdays, and five Sundays.
Task
Write a program to show all months that have this same characteristic of five full weekends from the year 1900 through 2100 (Gregorian calendar).
Show the number of months with this property (the... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Towers_of_Hanoi | Towers of Hanoi | Task
Solve the Towers of Hanoi problem with recursion.
| #Vedit_macro_language | Vedit macro language | #1=1; #2=2; #3=3; #4=4 // move 4 disks from 1 to 2
Call("MOVE_DISKS")
Return
// Move disks
// #1 = from, #2 = to, #3 = via, #4 = number of disks
//
:MOVE_DISKS:
if (#4 > 0) {
Num_Push(1,4)
#9=#2; #2=#3; #3=#9; #4-- // #1 to #3 via #2
Call("MOVE_DISKS")
Num_Pop(1,4)
Ins_Tex... | Give a code snippet in #Vedit_macro_language
Task
Solve the Towers of Hanoi problem with recursion.
| 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
... | #Bracmat | Bracmat | (comb=
bvar combination combinations list m n pat pvar var
. !arg:(?m.?n)
& ( pat
= ?
& !combinations (.!combination):?combinations
& ~
)
& :?list:?combination:?combinations
& whl
' ( !m+-1:~<0:?m
& chu$(utf$a+!m):?var
& glf$('(%@?.$var)):(=?pvar)
... | Give a code snippet in #Bracmat
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... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Four_bit_adder | Four bit adder | Task
"Simulate" a four-bit adder.
This design can be realized using four 1-bit full adders.
Each of these 1-bit full adders can be built with two half adders and an or gate. ;
Finally a half adder can be made using an xor gate and an and gate.
The xor gate can be made using two nots, two ands ... | #MUMPS | MUMPS | XOR(Y,Z) ;Uses logicals - i.e., 0 is false, anything else is true (1 is used if setting a value)
QUIT (Y&'Z)!('Y&Z)
HALF(W,X)
QUIT $$XOR(W,X)_"^"_(W&X)
FULL(U,V,CF)
NEW F1,F2
S F1=$$HALF(U,V)
S F2=$$HALF($P(F1,"^",1),CF)
QUIT $P(F2,"^",1)_"^"_($P(F1,"^",2)!($P(F2,"^",2)))
FOUR(Y,Z,C4)
NEW S,I,T
FOR I=4:-1:1 SET... | Give a code snippet in #MUMPS
Task
"Simulate" a four-bit adder.
This design can be realized using four 1-bit full adders.
Each of these 1-bit full adders can be built with two half adders and an or gate. ;
Finally a half adder can be made using an xor gate and an and gate.
The xor gate can be made ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Real_constants_and_functions | Real constants and functions | Task
Show how to use the following math constants and functions in your language (if not available, note it):
e (base of the natural logarithm)
π
{\displaystyle \pi }
square root
logarithm (any base allowed)
exponential (ex )
absolute value (a.k.a. "magnitude")
floor (largest ... | #AutoHotkey | AutoHotkey | Sqrt(Number) ; square root
Log(Number) ; logarithm (base 10)
Ln(Number) ; natural logarithm (base e)
Exp(N) ; e to the power N
Abs(Number) ; absolute value
Floor(Number) ; floor
Ceil(Number) ; ceiling
x**y ; x to the power y | Give a code snippet in #AutoHotkey
Task
Show how to use the following math constants and functions in your language (if not available, note it):
e (base of the natural logarithm)
π
{\displaystyle \pi }
square root
logarithm (any base allowed)
exponential (ex )
absolute value (a.k.... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Read_a_file_line_by_line | Read a file line by line | Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
| #RapidQ | RapidQ |
$Include "Rapidq.inc"
dim file as qfilestream
if file.open("c:\A Test.txt", fmOpenRead) then
while not File.eof
print File.readline
wend
else
print "Cannot read file"
end if
input "Press enter to exit: ";a$
| Give a code snippet in #RapidQ
Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
| 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... | #FOCAL | FOCAL | 1.1 F N=1,100;S D(N)=0
1.2 F M=1,100;F N=M,M,100;S D(N)=1-D(N)
1.3 F N=1,100;D 2.0
1.4 Q
2.1 I (D(N)),,2.2;R
2.2 T "OPEN DOOR ",%3.0,N,! | Give a code snippet in #FOCAL
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/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... | #CLU | CLU | % Generate the De Bruijn sequence consisiting of N-digit numbers
de_bruijn = cluster is generate
rep = null
own k: int := 0
own n: int := 0
own a: array[int] := array[int]$[]
own seq: array[int] := array[int]$[]
generate = proc (k_, n_: int) returns (string)
k := k_
n := n_
... | Give a code snippet in #CLU
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/Happy_numbers | Happy numbers | From Wikipedia, the free encyclopedia:
A happy number is defined by the following process:
Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not inclu... | #ACL2 | ACL2 | (include-book "arithmetic-3/top" :dir :system)
(defun sum-of-digit-squares (n)
(if (zp n)
0
(+ (expt (mod n 10) 2)
(sum-of-digit-squares (floor n 10)))))
(defun is-happy-r (n seen)
(let ((next (sum-of-digit-squares n)))
(cond ((= next 1) t)
((member next seen) nil... | Give a code snippet in #ACL2
From Wikipedia, the free encyclopedia:
A happy number is defined by the following process:
Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals 1 (where it will stay), or it loops endlessly i... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Generic_swap | Generic swap | Task
Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types.
If your solution language is statically typed please describe the way your language provides genericity.
If variables are typed in t... | #MATLAB_.2F_Octave | MATLAB / Octave | >> a = [30 40 50 60 70]
a =
30 40 50 60 70
>> a([1 3]) = a([3 1]) %Single swap
a =
50 40 30 60 70
>> a([1 2 4 3]) = a([2 3 1 4]) %Multiple swap, a.k.a permutation.
a =
40 30 60 50 70 | Give a code snippet in #MATLAB_.2F_Octave
Task
Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types.
If your solution language is statically typed please describe the way your language provid... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Four_bit_adder | Four bit adder | Task
"Simulate" a four-bit adder.
This design can be realized using four 1-bit full adders.
Each of these 1-bit full adders can be built with two half adders and an or gate. ;
Finally a half adder can be made using an xor gate and an and gate.
The xor gate can be made using two nots, two ands ... | #C.23 | C# |
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace RosettaCodeTasks.FourBitAdder
{
public struct BitAdderOutput
{
public bool S { get; set; }
public bool C { get; set; }
public override string ToString ( )
{
return "S" + ( S ? "1" : "0" ) + "C" + ( C ? "1" :... | Give a code snippet in #C.23
Task
"Simulate" a four-bit adder.
This design can be realized using four 1-bit full adders.
Each of these 1-bit full adders can be built with two half adders and an or gate. ;
Finally a half adder can be made using an xor gate and an and gate.
The xor gate can be made u... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loop_over_multiple_arrays_simultaneously | Loop over multiple arrays simultaneously | Task
Loop over multiple arrays (or lists or tuples or whatever they're called in
your language) and display the i th element of each.
Use your language's "for each" loop if it has one, otherwise iterate
through the collection in order with some other loop.
For this example, loop over the arrays:
... | #Golfscript | Golfscript | ["a" "b" "c"]:a;
["A" "B" "C"]:b;
["1" "2" "3"]:c;
[a b c]zip{puts}/ | Give a code snippet in #Golfscript
Task
Loop over multiple arrays (or lists or tuples or whatever they're called in
your language) and display the i th element of each.
Use your language's "for each" loop if it has one, otherwise iterate
through the collection in order with some other loop.
For this... | christopher/rosetta-code | |
http://rosettacode.org/wiki/HTTPS | HTTPS | Task
Send a GET request to obtain the resource located at the URL "https://www.w3.org/", then print it to the console.
Checking the host certificate for validity is recommended.
Do not authenticate. That is the subject of other tasks.
Readers may wish to contrast with the HTTP Request task, and also the task on HTT... | #TUSCRIPT | TUSCRIPT |
$$ MODE TUSCRIPT
SET DATEN = REQUEST ("https://sourceforge.net")
*{daten}
| Give a code snippet in #TUSCRIPT
Task
Send a GET request to obtain the resource located at the URL "https://www.w3.org/", then print it to the console.
Checking the host certificate for validity is recommended.
Do not authenticate. That is the subject of other tasks.
Readers may wish to contrast with the HTTP Requ... | 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 ... | #Prolog | Prolog | median(L, Z) :-
length(L, Length),
I is Length div 2,
Rem is Length rem 2,
msort(L, S),
maplist(sumlist, [[I, Rem], [I, 1]], Mid),
maplist(nth1, Mid, [S, S], X),
sumlist(X, Y),
Z is Y/2. | Give a code snippet in #Prolog
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/Parallel_calculations | Parallel calculations | Many programming languages allow you to specify computations to be run in parallel.
While Concurrent computing is focused on concurrency,
the purpose of this task is to distribute time-consuming calculations
on as many CPUs as possible.
Assume we have a collection of numbers, and want to find the one
with the largest ... | #Mathematica.2FWolfram_Language | Mathematica/Wolfram Language | hasSmallestFactor[data_List]:=Sort[Transpose[{ParallelTable[FactorInteger[x][[1, 1]], {x, data}],data}]][[1, 2]] | Give a code snippet in #Mathematica.2FWolfram_Language
Many programming languages allow you to specify computations to be run in parallel.
While Concurrent computing is focused on concurrency,
the purpose of this task is to distribute time-consuming calculations
on as many CPUs as possible.
Assume we have a collectio... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Closures/Value_capture | Closures/Value capture | Task
Create a list of ten functions, in the simplest manner possible (anonymous functions are encouraged), such that the function at index i (you may choose to start i from either 0 or 1), when run, should return the square of the index, that is, i 2.
Display the result of runnin... | #Phix | Phix | with javascript_semantics
-- First some generic handling stuff, handles partial_args
-- of any mixture of any length and element types.
sequence closures = {}
function add_closure(integer rid, sequence partial_args)
closures = append(closures,{rid,partial_args})
return length(closures) -- (return an integer id)... | Give a code snippet in #Phix
Task
Create a list of ten functions, in the simplest manner possible (anonymous functions are encouraged), such that the function at index i (you may choose to start i from either 0 or 1), when run, should return the square of the index, that is, i 2.... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Parametric_polymorphism | Parametric polymorphism | Parametric Polymorphism
type variables
Task
Write a small example for a type declaration that is parametric over another type, together with a short bit of code (and its type signature) that uses it.
A good example is a container type, let's say a binary tree, together with some function that traverses the tree, ... | #Racket | Racket |
#lang typed/racket
(define-type (Tree A) (U False (Node A)))
(struct: (A) Node
([val : A] [left : (Tree A)] [right : (Tree A)])
#:transparent)
(: tree-map (All (A B) (A -> B) (Tree A) -> (Tree B)))
(define (tree-map f tree)
(match tree
[#f #f]
[(Node val left right)
(Node (f val) (tree-map f ... | Give a code snippet in #Racket
Parametric Polymorphism
type variables
Task
Write a small example for a type declaration that is parametric over another type, together with a short bit of code (and its type signature) that uses it.
A good example is a container type, let's say a binary tree, together with some fu... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Define_a_primitive_data_type | Define a primitive data type | Demonstrate how to define a type that behaves like an integer but has a lowest valid value of 1 and a highest valid value of 10. Include all bounds checking you need to write, or explain how the compiler or interpreter creates those bounds checks for you.
| #OCaml | OCaml | exception Out_of_bounds
type 'a bounds = { min: 'a; max: 'a }
type 'a bounded = { value: 'a; bounds: 'a bounds }
let mk_bounds ~min ~max = { min=min; max=max } ;;
(** val mk_bounds : min:'a -> max:'a -> 'a bounds *)
let check_bounds ~value ~bounds =
if value < bounds.min || value > bounds.max then
raise O... | Give a code snippet in #OCaml
Demonstrate how to define a type that behaves like an integer but has a lowest valid value of 1 and a highest valid value of 10. Include all bounds checking you need to write, or explain how the compiler or interpreter creates those bounds checks for you.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Matrix_transposition | Matrix transposition | Transpose an arbitrarily sized rectangular Matrix.
| #MATLAB | MATLAB | >> transpose([1 2;3 4])
ans =
1 3
2 4
>> [1 2;3 4].'
ans =
1 3
2 4 | Give a code snippet in #MATLAB
Transpose an arbitrarily sized rectangular Matrix.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/String_case | String case | Task
Take the string alphaBETA and demonstrate how to convert it to:
upper-case and
lower-case
Use the default encoding of a string literal or plain ASCII if there is no string literal in your language.
Note: In some languages alphabets toLower and toUpper is not reversable.
Show any additional... | #Sed | Sed | echo "alphaBETA" | sed 'y/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/'
echo "alphaBETA" | sed 'y/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/' | Give a code snippet in #Sed
Task
Take the string alphaBETA and demonstrate how to convert it to:
upper-case and
lower-case
Use the default encoding of a string literal or plain ASCII if there is no string literal in your language.
Note: In some languages alphabets toLower and toUpper is not rev... | 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.
| #8080_Assembly | 8080 Assembly | org 100h
jmp demo
;;; Given an 0-terminated ASCII string containing digits in [DE],
;;; see if it matches its check digit. Returns with zero flag set
;;; if the string matches.
damm: mvi c,0 ; Interim digit in C, starts off at 0.
ldax d ; Get current byte from string
inx d ; Advance the pointer
ana a ; Is the ... | Give a code snippet in #8080_Assembly
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/String_length | String length | Task
Find the character and byte length of a string.
This means encodings like UTF-8 need to be handled properly, as there is not necessarily a one-to-one relationship between bytes and characters.
By character, we mean an individual Unicode code point, not a user-visible grapheme containing combining characters.
F... | #Oberon-2 | Oberon-2 | MODULE Size;
IMPORT Out;
VAR s: LONGINT;
string: ARRAY 5 OF CHAR;
BEGIN
string := "Foo";
s := LEN(string);
Out.String("Size: ");
Out.LongInt(s,0);
Out.Ln;
END Size. | Give a code snippet in #Oberon-2
Task
Find the character and byte length of a string.
This means encodings like UTF-8 need to be handled properly, as there is not necessarily a one-to-one relationship between bytes and characters.
By character, we mean an individual Unicode code point, not a user-visible grapheme c... | 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... | #Julia | Julia | using Formatting
setprecision(BigFloat, 300)
function integerterm(n)
p = BigInt(532) * n * n + BigInt(126) * n + 9
return (p * BigInt(2)^5 * factorial(BigInt(6) * n)) ÷ (3 * factorial(BigInt(n))^6)
end
exponentterm(n) = -(6n + 3)
nthterm(n) = integerterm(n) * big"10.0"^exponentterm(n)
println(" N ... | Give a code snippet in #Julia
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
Thi... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Singly-linked_list/Element_definition | Singly-linked list/Element definition | singly-linked list
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked list: Element definition, Element insertion, Lis... | #J | J | list=: 0 2$0
list | Give a code snippet in #J
singly-linked list
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked list: Element definit... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sylvester%27s_sequence | Sylvester's sequence |
This page uses content from Wikipedia. The original article was at Sylvester's sequence. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
In number theory, Sylvester's sequence is an integer sequenc... | #Haskell | Haskell | sylvester :: [Integer]
sylvester = map s [0 ..]
where
s 0 = 2
s n = succ $ foldr ((*) . s) 1 [0 .. pred n]
main :: IO ()
main = do
putStrLn "First 10 elements of Sylvester's sequence:"
putStr $ unlines $ map show $ take 10 sylvester
putStr "\nSum of reciprocals by sum over map: "
print $ sum $ map... | Give a code snippet in #Haskell
This page uses content from Wikipedia. The original article was at Sylvester's sequence. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
In number theory, Sylvester... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Assertions | Assertions | Assertions are a way of breaking out of code when there is an error or an unexpected input.
Some languages throw exceptions and some treat it as a break point.
Task
Show an assertion in your language by asserting that an integer variable is equal to 42.
| #Go | Go | package main
func main() {
x := 43
if x != 42 {
panic(42)
}
} | Give a code snippet in #Go
Assertions are a way of breaking out of code when there is an error or an unexpected input.
Some languages throw exceptions and some treat it as a break point.
Task
Show an assertion in your language by asserting that an integer variable is equal to 42.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/String_case | String case | Task
Take the string alphaBETA and demonstrate how to convert it to:
upper-case and
lower-case
Use the default encoding of a string literal or plain ASCII if there is no string literal in your language.
Note: In some languages alphabets toLower and toUpper is not reversable.
Show any additional... | #Java | Java | String str = "alphaBETA";
System.out.println(str.toUpperCase());
System.out.println(str.toLowerCase());
//Also works with non-English characters with no modification
System.out.println("äàâáçñßæεбế".toUpperCase());
System.out.println("ÄÀÂÁÇÑSSÆΕБẾ".toLowerCase()); //does not transalate "SS" to "ß" | Give a code snippet in #Java
Task
Take the string alphaBETA and demonstrate how to convert it to:
upper-case and
lower-case
Use the default encoding of a string literal or plain ASCII if there is no string literal in your language.
Note: In some languages alphabets toLower and toUpper is not re... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Miller%E2%80%93Rabin_primality_test | Miller–Rabin primality test |
This page uses content from Wikipedia. The original article was at Miller–Rabin primality test. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
The Miller–Rabin primality test or Rabin–Miller prima... | #Python | Python |
import random
def is_Prime(n):
"""
Miller-Rabin primality test.
A return value of False means n is certainly not prime. A return value of
True means n is very likely a prime.
"""
if n!=int(n):
return False
n=int(n)
#Miller-Rabin test for prime
if n==0 or n==1 or n==4 ... | Give a code snippet in #Python
This page uses content from Wikipedia. The original article was at Miller–Rabin primality test. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
The Miller–Rabin prim... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Echo_server | Echo server | Create a network service that sits on TCP port 12321, which accepts connections on that port, and which echoes complete lines (using a carriage-return/line-feed sequence as line separator) back to clients. No error handling is required. For the purposes of testing, it is only necessary to support connections from local... | #PureBasic | PureBasic | NewMap RecData.s()
OpenWindow(0, 100, 200, 200, 100, "Echo Server", #PB_Window_SystemMenu | #PB_Window_MinimizeGadget )
InitNetwork()
CreateNetworkServer(1, 12321)
Repeat
Event = NetworkServerEvent()
ClientID = EventClient()
If Event = #PB_NetworkEvent_Connect ; When a new client has been connected...
... | Give a code snippet in #PureBasic
Create a network service that sits on TCP port 12321, which accepts connections on that port, and which echoes complete lines (using a carriage-return/line-feed sequence as line separator) back to clients. No error handling is required. For the purposes of testing, it is only necessar... | christopher/rosetta-code | |
http://rosettacode.org/wiki/HTTPS | HTTPS | Task
Send a GET request to obtain the resource located at the URL "https://www.w3.org/", then print it to the console.
Checking the host certificate for validity is recommended.
Do not authenticate. That is the subject of other tasks.
Readers may wish to contrast with the HTTP Request task, and also the task on HTT... | #Common_Lisp | Common Lisp |
(defun wget-drakma-string (url &optional (out *standard-output*))
"Grab the body as a string, and write it to out."
(write-string (drakma:http-request url) out))
(defun wget-drakma-stream (url &optional (out *standard-output*))
"Grab the body as a stream, and write it to out."
(loop with body = (drakma:http... | Give a code snippet in #Common_Lisp
Task
Send a GET request to obtain the resource located at the URL "https://www.w3.org/", then print it to the console.
Checking the host certificate for validity is recommended.
Do not authenticate. That is the subject of other tasks.
Readers may wish to contrast with the HTTP R... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Dragon_curve | Dragon curve |
Create and display a dragon curve fractal.
(You may either display the curve directly or write it to an image file.)
Algorithms
Here are some brief notes the algorithms used and how they might suit various languages.
Recursively a right curling dragon is a right dragon followed by a left dragon, at 90-degree an... | #Tcl | Tcl | package require Tk
set pi [expr acos(-1)]
set r2 [expr sqrt(2)]
proc turn {degrees} {
global a pi
set a [expr {$a + $degrees*$pi/180}]
}
proc forward {len} {
global a coords
lassign [lrange $coords end-1 end] x y
lappend coords [expr {$x + cos($a)*$len}] [expr {$y + sin($a)*$len}]
}
proc dragon ... | Give a code snippet in #Tcl
Create and display a dragon curve fractal.
(You may either display the curve directly or write it to an image file.)
Algorithms
Here are some brief notes the algorithms used and how they might suit various languages.
Recursively a right curling dragon is a right dragon followed by a... | christopher/rosetta-code | |
http://rosettacode.org/wiki/IBAN | IBAN |
This page uses content from Wikipedia. The original article was at IBAN. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
The International Bank Account Number (IBAN) is an internationally agree... | #Common_Lisp | Common Lisp |
;;
;; List of the IBAN code lengths per country.
;;
(defvar *IBAN-code-length* '((15 . ("NO"))
(16 . ("BE"))
(18 . ("DK" "FO" "FI" "GL" "NL"))
(19 . ("MK" "SI"))
(20 . ("AT" "BA" "EE" "KZ" "LT" "LU"))... | Give a code snippet in #Common_Lisp
This page uses content from Wikipedia. The original article was at IBAN. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
The International Bank Account Number... | christopher/rosetta-code | |
http://rosettacode.org/wiki/MD5 | MD5 | Task
Encode a string using an MD5 algorithm. The algorithm can be found on Wikipedia.
Optionally, validate your implementation by running all of the test values in IETF RFC (1321) for MD5.
Additionally, RFC 1321 provides more precise information on the algorithm than the Wikipedia article.
Warning:... | #Common_Lisp | Common Lisp | (ql:quickload 'ironclad)
(defun md5 (str)
(ironclad:byte-array-to-hex-string
(ironclad:digest-sequence :md5
(ironclad:ascii-string-to-byte-array str))))
(defvar *tests* '(""
"a"
"abc"
"message digest"
"abcdefgh... | Give a code snippet in #Common_Lisp
Task
Encode a string using an MD5 algorithm. The algorithm can be found on Wikipedia.
Optionally, validate your implementation by running all of the test values in IETF RFC (1321) for MD5.
Additionally, RFC 1321 provides more precise information on the algorithm tha... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Stack | Stack |
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
A stack is a container of elements with last in, first out access policy. Sometimes it also called LIFO.
The stack is accessed through its top.
The ba... | #ATS | ATS | (* Stacks implemented as linked lists. *)
(* A nonlinear stack type of size n, which is good for when you are
using a garbage collector or can let the memory leak. *)
typedef stack_t (t : t@ype+, n : int) = list (t, n)
typedef stack_t (t : t@ype+) = [n : int] stack_t (t, n)
(* A linear stack type of size n, whic... | Give a code snippet in #ATS
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
A stack is a container of elements with last in, first out access policy. Sometimes it also called LIFO.
The stack is acce... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Execute_a_system_command | Execute a system command | Task
Run either the ls system command (dir on Windows), or the pause system command.
Related task
Get system command output
| #UNIX_Shell | UNIX Shell | ls | Give a code snippet in #UNIX_Shell
Task
Run either the ls system command (dir on Windows), or the pause system command.
Related task
Get system command output
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Primality_by_trial_division | Primality by trial division | Task
Write a boolean function that tells whether a given integer is prime.
Remember that 1 and all non-positive numbers are not prime.
Use trial division.
Even numbers greater than 2 may be eliminated right away.
A loop from 3 to √ n will suffice, but other loops are allowed.
Related tasks
... | #Standard_ML | Standard ML | fun is_prime n =
if n = 2 then true
else if n < 2 orelse n mod 2 = 0 then false
else let
fun loop k =
if k * k > n then true
else if n mod k = 0 then false
else loop (k+2)
in loop 3
end | Give a code snippet in #Standard_ML
Task
Write a boolean function that tells whether a given integer is prime.
Remember that 1 and all non-positive numbers are not prime.
Use trial division.
Even numbers greater than 2 may be eliminated right away.
A loop from 3 to √ n will suffice, but other... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Move-to-front_algorithm | Move-to-front algorithm | Given a symbol table of a zero-indexed array of all possible input symbols
this algorithm reversibly transforms a sequence
of input symbols into an array of output numbers (indices).
The transform in many cases acts to give frequently repeated input symbols
lower indices which is useful in some compression algorithms... | #Mathematica.2FWolfram_Language | Mathematica/Wolfram Language | mtf[word_]:=Module[{f,f2,p,q},
f[{output_,symList_},next_]:=Module[{index},index=Position[symList,next][[1,1]]-1;
{output~Append~index,Prepend[Delete[symList,index+1],next]}];
p=Fold[f,{{},CharacterRange["a","z"]},Characters[ToString[word]]][[1]];
f2[{output_,symList_},next_]:=Module[{index},index=symLi... | Give a code snippet in #Mathematica.2FWolfram_Language
Given a symbol table of a zero-indexed array of all possible input symbols
this algorithm reversibly transforms a sequence
of input symbols into an array of output numbers (indices).
The transform in many cases acts to give frequently repeated input symbols
lower... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Runge-Kutta_method | Runge-Kutta method | Given the example Differential equation:
y
′
(
t
)
=
t
×
y
(
t
)
{\displaystyle y'(t)=t\times {\sqrt {y(t)}}}
With initial condition:
t
0
=
0
{\displaystyle t_{0}=0}
and
y
0
=
y
(
t
0
)
=
y
(
0
)
=
1
{\displaystyle y_{0}=y(t_{0})=y(0)=1}
This equation has an exact solution:
... | #Maxima | Maxima | /* Here is how to solve a differential equation */
'diff(y, x) = x * sqrt(y);
ode2(%, y, x);
ic1(%, x = 0, y = 1);
factor(solve(%, y)); /* [y = (x^2 + 4)^2 / 16] */
/* The Runge-Kutta solver is builtin */
load(dynamics)$
sol: rk(t * sqrt(y), y, 1, [t, 0, 10, 1.0])$
plot2d([discrete, sol])$
/* An implementation of... | Give a code snippet in #Maxima
Given the example Differential equation:
y
′
(
t
)
=
t
×
y
(
t
)
{\displaystyle y'(t)=t\times {\sqrt {y(t)}}}
With initial condition:
t
0
=
0
{\displaystyle t_{0}=0}
and
y
0
=
y
(
t
0
)
=
y
(
0
)
=
1
{\displaystyle y_{0}=y(t_{0})=y(0)=1}
This e... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Arrays | Arrays | This task is about arrays.
For hashes or associative arrays, please see Creating an Associative Array.
For a definition and in-depth discussion of what an array is, see Array.
Task
Show basic array syntax in your language.
Basically, create an array, assign a value to it, and retrieve an element (if available,... | #Gambas | Gambas |
DIM mynumbers AS INTEGER[]
myfruits AS STRING[]
mynumbers[0] = 1.5
mynumbers[1] = 2.3
myfruits[0] = "apple"
myfruits[1] = "banana"
| Give a code snippet in #Gambas
This task is about arrays.
For hashes or associative arrays, please see Creating an Associative Array.
For a definition and in-depth discussion of what an array is, see Array.
Task
Show basic array syntax in your language.
Basically, create an array, assign a value to it, and retr... | christopher/rosetta-code | |
http://rosettacode.org/wiki/List_comprehensions | List comprehensions | A list comprehension is a special syntax in some programming languages to describe lists. It is similar to the way mathematicians describe sets, with a set comprehension, hence the name.
Some attributes of a list comprehension are:
They should be distinct from (nested) for loops and the use of map and filter functio... | #C.23 | C# | using System.Linq;
static class Program
{
static void Main()
{
var ts =
from a in Enumerable.Range(1, 20)
from b in Enumerable.Range(a, 21 - a)
from c in Enumerable.Range(b, 21 - b)
where a * a + b * b == c * c
select new { a, b, c };
foreach (var t in ts)
System.... | Give a code snippet in #C.23
A list comprehension is a special syntax in some programming languages to describe lists. It is similar to the way mathematicians describe sets, with a set comprehension, hence the name.
Some attributes of a list comprehension are:
They should be distinct from (nested) for loops and the... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Jump_anywhere | Jump anywhere | Imperative programs
conditional structures
loops
local jumps
This task is to demonstrate a local jump and a global jump and the various other types of jumps that the language supports.
For the purpose of this task, the jumps need not be used for a single purpose and you have the freedom to use these jumps for different... | #PARI.2FGP | PARI/GP | sub outer {
print "In outer, calling inner:\n";
inner();
OUTER:
print "at label OUTER\n";
}
sub inner {
print "In inner\n";
goto SKIP; # goto same block level
print "This should be skipped\n";
SKIP:
print "at label SKIP\n";
goto OUTER; # goto whatever OUTER label there... | Give a code snippet in #PARI.2FGP
Imperative programs
conditional structures
loops
local jumps
This task is to demonstrate a local jump and a global jump and the various other types of jumps that the language supports.
For the purpose of this task, the jumps need not be used for a single purpose and you have the freed... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sum_of_elements_below_main_diagonal_of_matrix | Sum of elements below main diagonal of matrix | Task
Find and display the sum of elements that are below the main diagonal of a matrix.
The matrix should be a square matrix.
─── Matrix to be used: ───
[[1,3,7,8,10],
[2,4,16,14,4],
[3,1,9,18,11],
[12,14,17,18,20],
[7,1,3,9,5]]
| #Phix | Phix | constant M = {{ 1, 3, 7, 8, 10},
{ 2, 4, 16, 14, 4},
{ 3, 1, 9, 18, 11},
{12, 14, 17, 18, 20},
{ 7, 1, 3, 9, 5}}
atom res = 0
integer height = length(M)
for row=1 to height do
integer width = length(M[row])
if width!=height then crash("not squar... | Give a code snippet in #Phix
Task
Find and display the sum of elements that are below the main diagonal of a matrix.
The matrix should be a square matrix.
─── Matrix to be used: ───
[[1,3,7,8,10],
[2,4,16,14,4],
[3,1,9,18,11],
[12,14,17,18,20],
[7,1,3,9,5]]
| 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... | #VBA | VBA |
Option Explicit
Sub Main_Conv_Temp()
Dim K As Single, Result As Single
K = 21
Debug.Print "Input in Kelvin : " & Format(K, "0.00")
Debug.Print "Output in Celsius : " & IIf(ConvTemp(Result, K, "C"), Format(Result, "0.00"), False)
Debug.Print "Output in Fahrenheit : " & IIf(ConvTemp(Result, K,... | Give a code snippet in #VBA
There are quite a number of temperature scales. For this task we will concentrate on four of the perhaps best-known ones:
Kelvin, Celsius, Fahrenheit, and Rankine.
The Celsius and Kelvin scales have the same magnitude, but different null points.
0 degrees Celsius corresponds to 273.15 ke... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Euler%27s_sum_of_powers_conjecture | Euler's sum of powers conjecture | There is a conjecture in mathematics that held for over two hundred years before it was disproved by the finding of a counterexample in 1966 by Lander and Parkin.
Euler's (disproved) sum of powers conjecture
At least k positive kth powers are required to sum to a kth power,
except for the trivial case... | #Raku | Raku | constant MAX = 250;
my %po5{Int};
my %sum2{Int};
(1..MAX).map: -> $i {
%po5{$i**5} = $i;
for 1..MAX -> $j {
%sum2{$i**5 + $j**5} = ($i, $j);
}
}
my @sk = %sum2.keys.sort;
%po5.keys.sort.race.map: -> $p {
for @sk -> $s {
next if $p <= $s;
if %sum2{$p - $s} {
say ... | Give a code snippet in #Raku
There is a conjecture in mathematics that held for over two hundred years before it was disproved by the finding of a counterexample in 1966 by Lander and Parkin.
Euler's (disproved) sum of powers conjecture
At least k positive kth powers are required to sum to a kth power, ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sum_to_100 | Sum to 100 | Task
Find solutions to the sum to one hundred puzzle.
Add (insert) the mathematical
operators + or - (plus
or minus) before any of the digits in the
decimal numeric string 123456789 such that the
resulting mathematical expression adds up to a
particular sum (in this iconic case, ... | #zkl | zkl | var all = // ( (1,12,123...-1,-12,...), (2,23,...) ...)
(9).pump(List,fcn(n){ split("123456789"[n,*]) }) // 45
.apply(fcn(ns){ ns.extend(ns.copy().apply('*(-1))) }); // 90
fcn calcAllSums{ // calculate all 6572 sums (1715 unique)
fcn(n,sum,soFar,r){
if(n==9) return();
foreach b in (all[n]){... | Give a code snippet in #zkl
Task
Find solutions to the sum to one hundred puzzle.
Add (insert) the mathematical
operators + or - (plus
or minus) before any of the digits in the
decimal numeric string 123456789 such that the
resulting mathematical expression adds up to a
particular s... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Maze_generation | Maze generation |
This page uses content from Wikipedia. The original article was at Maze generation algorithm. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
Task
Generate and show a maze, using the simple Depth... | #Julia | Julia | using Random
check(bound::Vector) = cell -> all([1, 1] .≤ cell .≤ bound)
neighbors(cell::Vector, bound::Vector, step::Int=2) =
filter(check(bound), map(dir -> cell + step * dir, [[0, 1], [-1, 0], [0, -1], [1, 0]]))
function walk(maze::Matrix, nxtcell::Vector, visited::Vector=[])
push!(visited, nxtcell)
fo... | Give a code snippet in #Julia
This page uses content from Wikipedia. The original article was at Maze generation algorithm. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
Task
Generate and show... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Function_composition | Function composition | Task
Create a function, compose, whose two arguments f and g, are both functions with one argument.
The result of compose is to be a function of one argument, (lets call the argument x), which works like applying function f to the result of applying function g to x.
Example
compose... | #Phix | Phix | sequence ctable = {}
function compose(integer f, integer g)
ctable = append(ctable,{f,g})
return length(ctable)
end function
function call_composite(integer f, atom x)
integer g
{f,g} = ctable[f]
return call_func(f,{call_func(g,{x})})
end function
function plus1(atom x)
return x+1
end funct... | Give a code snippet in #Phix
Task
Create a function, compose, whose two arguments f and g, are both functions with one argument.
The result of compose is to be a function of one argument, (lets call the argument x), which works like applying function f to the result of applying function g ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Increment_a_numerical_string | Increment a numerical string | Task
Increment a numerical string.
| #JavaScript | JavaScript | let s = '9999';
let splusplus = (+s+1)+""
console.log([splusplus, typeof splusplus]) // 10000,string | Give a code snippet in #JavaScript
Task
Increment a numerical string.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Forth | Forth | \ args.f: print each command line argument on a separate line
: main
argc @ 0 do i arg type cr loop ;
main bye | Give a code snippet in #Forth
Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| christopher/rosetta-code | |
http://rosettacode.org/wiki/First-class_functions | First-class functions | A language has first-class functions if it can do each of the following without recursively invoking a compiler or interpreter or otherwise metaprogramming:
Create new functions from preexisting functions at run-time
Store functions in collections
Use functions as arguments to other functions
Use functions as retu... | #Axiom | Axiom | fns := [sin$Float, cos$Float, (x:Float):Float +-> x^3]
inv := [asin$Float, acos$Float, (x:Float):Float +-> x^(1/3)]
[(f*g) 0.5 for f in fns for g in inv] | Give a code snippet in #Axiom
A language has first-class functions if it can do each of the following without recursively invoking a compiler or interpreter or otherwise metaprogramming:
Create new functions from preexisting functions at run-time
Store functions in collections
Use functions as arguments to other f... | 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... | #Standard_ML | Standard ML | #!/usr/bin/env sml
let
val program = CommandLine.name ()
in
print ("Program: " ^ program ^ "\n")
end; | Give a code snippet in #Standard_ML
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 s... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Find_the_intersection_of_two_lines | Find the intersection of two lines | [1]
Task
Find the point of intersection of two lines in 2D.
The 1st line passes though (4,0) and (6,10) .
The 2nd line passes though (0,3) and (10,7) .
| #F.23 | F# |
(*
Find the point of intersection of 2 lines.
Nigel Galloway May 20th., 2017
*)
type Line={a:float;b:float;c:float} member N.toS=sprintf "%.2fx + %.2fy = %.2f" N.a N.b N.c
let intersect (n:Line) g = match (n.a*g.b-g.a*n.b) with
|0.0 ->printfn "%s does not intersect %s" n.toS g.toS
... | Give a code snippet in #F.23
[1]
Task
Find the point of intersection of two lines in 2D.
The 1st line passes though (4,0) and (6,10) .
The 2nd line passes though (0,3) and (10,7) .
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Sequence_of_primes_by_trial_division | Sequence of primes by trial division | Sequence of primes by trial division
You are encouraged to solve this task according to the task description, using any language you may know.
Task
Generate a sequence of primes by means of trial division.
Trial division is an algorithm where a candidate number is tested for being a prime by trying to divide it by... | #Ruby | Ruby | require "prime"
pg = Prime::TrialDivisionGenerator.new
p pg.take(10) # => [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]
p pg.next # => 31 | Give a code snippet in #Ruby
Sequence of primes by trial division
You are encouraged to solve this task according to the task description, using any language you may know.
Task
Generate a sequence of primes by means of trial division.
Trial division is an algorithm where a candidate number is tested for being a p... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Integer_sequence | Integer sequence | Task
Create a program that, when run, would display all integers from 1 to ∞ (or any relevant implementation limit), in sequence (i.e. 1, 2, 3, 4, etc) if given enough time.
An example may not be able to reach arbitrarily-large numbers based on implementations limits. For example, if integer... | #ChucK | ChucK |
for(1 => int i; i < Math.INT_MAX; i ++)
{
<<< i >>>;
}
| Give a code snippet in #ChucK
Task
Create a program that, when run, would display all integers from 1 to ∞ (or any relevant implementation limit), in sequence (i.e. 1, 2, 3, 4, etc) if given enough time.
An example may not be able to reach arbitrarily-large numbers based on implementations li... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Truncate_a_file | Truncate a file | Task
Truncate a file to a specific length. This should be implemented as a routine that takes two parameters: the filename and the required file length (in bytes).
Truncation can be achieved using system or library calls intended for such a task, if such methods exist, or by creating a temporary file of a reduced... | #Ring | Ring |
file = "C:\Ring\ReadMe.txt"
fp = read(file)
fpstr = left(fp, 100)
see fpstr + nl
write(file, fpstr)
| Give a code snippet in #Ring
Task
Truncate a file to a specific length. This should be implemented as a routine that takes two parameters: the filename and the required file length (in bytes).
Truncation can be achieved using system or library calls intended for such a task, if such methods exist, or by creating... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Averages/Simple_moving_average | Averages/Simple moving average | Computing the simple moving average of a series of numbers.
Task[edit]
Create a stateful function/class/instance that takes a period and returns a routine that takes a number as argument and returns a simple moving average of its arguments so far.
Description
A simple moving average is a method for computing an avera... | #ooRexx | ooRexx |
testdata = .array~of(1, 2, 3, 4, 5, 5, 4, 3, 2, 1)
-- run with different period sizes
loop period over .array~of(3, 5)
say "Period size =" period
say
movingaverage = .movingaverage~new(period)
loop number over testdata
average = movingaverage~addnumber(number)
say " Next number =" ... | Give a code snippet in #ooRexx
Computing the simple moving average of a series of numbers.
Task[edit]
Create a stateful function/class/instance that takes a period and returns a routine that takes a number as argument and returns a simple moving average of its arguments so far.
Description
A simple moving average is... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Safe_primes_and_unsafe_primes | Safe primes and unsafe primes | Definitions
A safe prime is a prime p and where (p-1)/2 is also prime.
The corresponding prime (p-1)/2 is known as a Sophie Germain prime.
An unsafe prime is a prime p and where (p-1)/2 isn't a prime.
An unsafe prime is a prime that isn't a safe prime.
Task
... | #Visual_Basic_.NET | Visual Basic .NET | Imports System.Console
Namespace safety
Module SafePrimes
Dim pri_HS As HashSet(Of Integer) = Primes(10_000_000).ToHashSet()
Sub Main()
For Each UnSafe In {False, True} : Dim n As Integer = If(UnSafe, 40, 35)
WriteLine($"The first {n} {If(UnSafe, "un", "")}safe primes... | Give a code snippet in #Visual_Basic_.NET
Definitions
A safe prime is a prime p and where (p-1)/2 is also prime.
The corresponding prime (p-1)/2 is known as a Sophie Germain prime.
An unsafe prime is a prime p and where (p-1)/2 isn't a prime.
An unsafe prime is a prime... | 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.)
| #ProDOS | ProDOS | IGNORELINE your text here | Give a code snippet in #ProDOS
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/Towers_of_Hanoi | Towers of Hanoi | Task
Solve the Towers of Hanoi problem with recursion.
| #Batch_File | Batch File | @echo off
setlocal enabledelayedexpansion
%==The main thing==%
%==First param - Number of disks==%
%==Second param - Start pole==%
%==Third param - End pole==%
%==Fourth param - Helper pole==%
call :move 4 START END HELPER
echo.
pause
exit /b 0
%==The "function"==%
:move
setlocal
set n=%1
set from=%2
set ... | Give a code snippet in #Batch_File
Task
Solve the Towers of Hanoi problem with recursion.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Find_the_missing_permutation | Find the missing permutation | ABCD
CABD
ACDB
DACB
BCDA
ACBD
ADCB
CDAB
DABC
BCAD
CADB
CDBA
... | #C | C | #include <stdio.h>
#define N 4
const char *perms[] = {
"ABCD", "CABD", "ACDB", "DACB", "BCDA", "ACBD", "ADCB", "CDAB",
"DABC", "BCAD", "CADB", "CDBA", "CBAD", "ABDC", "ADBC", "BDCA",
"DCBA", "BACD", "BADC", "BDAC", "CBDA", "DBCA", "DCAB",
};
int main()
{
int i, j, n, cnt[N];
char miss[N];
for (n = i = 1; i ... | Give a code snippet in #C
ABCD
CABD
ACDB
DACB
BCDA
ACBD
ADCB
CDAB
DABC
BCAD
CADB
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Nth_root | Nth root | Task
Implement the algorithm to compute the principal nth root
A
n
{\displaystyle {\sqrt[{n}]{A}}}
of a positive real number A, as explained at the Wikipedia page.
| #JavaScript | JavaScript | function nthRoot(num, nArg, precArg) {
var n = nArg || 2;
var prec = precArg || 12;
var x = 1; // Initial guess.
for (var i=0; i<prec; i++) {
x = 1/n * ((n-1)*x + (num / Math.pow(x, n-1)));
}
return x;
} | Give a code snippet in #JavaScript
Task
Implement the algorithm to compute the principal nth root
A
n
{\displaystyle {\sqrt[{n}]{A}}}
of a positive real number A, as explained at the Wikipedia page.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Disarium_numbers | Disarium numbers | A Disarium number is an integer where the sum of each digit raised to the power of its position in the number, is equal to the number.
E.G.
135 is a Disarium number:
11 + 32 + 53 == 1 + 9 + 125 == 135
There are a finite number of Disarium numbers.
Task
Find and display the first 18 Disarium numbers.
Stretch... | #Sidef | Sidef | func is_disarium(n) {
n.digits.flip.sum_kv{|k,d| d**(k+1) } == n
}
say 18.by(is_disarium) | Give a code snippet in #Sidef
A Disarium number is an integer where the sum of each digit raised to the power of its position in the number, is equal to the number.
E.G.
135 is a Disarium number:
11 + 32 + 53 == 1 + 9 + 125 == 135
There are a finite number of Disarium numbers.
Task
Find and display the first... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Iterated_digits_squaring | Iterated digits squaring | If you add the square of the digits of a Natural number (an integer bigger than zero), you always end with either 1 or 89:
15 -> 26 -> 40 -> 16 -> 37 -> 58 -> 89
7 -> 49 -> 97 -> 130 -> 10 -> 1
An example in Python:
>>> step = lambda x: sum(int(d) ** 2 for d in str(x))
>>> iterate = lambda x: x if x in [1, 89] else i... | #Factor | Factor | USING: kernel math math.ranges math.text.utils memoize
prettyprint sequences tools.time ;
IN: rosetta-code.iterated-digits-squaring
: sum-digit-sq ( n -- m ) 1 digit-groups [ sq ] map-sum ;
MEMO: 1or89 ( n -- m )
[ dup [ 1 = ] [ 89 = ] bi or ] [ sum-digit-sq ] until ;
[
0 1
[
dup sum-digit-sq ... | Give a code snippet in #Factor
If you add the square of the digits of a Natural number (an integer bigger than zero), you always end with either 1 or 89:
15 -> 26 -> 40 -> 16 -> 37 -> 58 -> 89
7 -> 49 -> 97 -> 130 -> 10 -> 1
An example in Python:
>>> step = lambda x: sum(int(d) ** 2 for d in str(x))
>>> iterate = la... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Abbreviations,_automatic | Abbreviations, automatic | The use of abbreviations (also sometimes called synonyms, nicknames, AKAs, or aliases) can be an
easy way to add flexibility when specifying or using commands, sub─commands, options, etc.
It would make a list of words easier to maintain (as words are added, changed, and/or deleted) if
the minimum abbrevia... | #Perl | Perl | use strict;
use utf8;
binmode STDOUT, ":utf8";
sub auto_abbreviate {
my($string) = @_;
my @words = split ' ', $string;
my $max = 0;
return '' unless @words;
map { $max = length($_) if length($_) > $max } @words;
for $i (1..$max) {
my %seen;
return $i if @words == grep {!$seen{s... | Give a code snippet in #Perl
The use of abbreviations (also sometimes called synonyms, nicknames, AKAs, or aliases) can be an
easy way to add flexibility when specifying or using commands, sub─commands, options, etc.
It would make a list of words easier to maintain (as words are added, changed, and/or dele... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Stack | Stack |
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
A stack is a container of elements with last in, first out access policy. Sometimes it also called LIFO.
The stack is accessed through its top.
The ba... | #Common_Lisp | Common Lisp | (defstruct stack
elements)
(defun stack-push (element stack)
(push element (stack-elements stack)))
(defun stack-pop (stack)(deftype Stack [elements])
(defun stack-empty (stack)
(endp (stack-elements stack)))
(defun stack-top (stack)
(first (stack-elements stack)))
(defun stack-peek (stack)
(stack-t... | Give a code snippet in #Common_Lisp
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
A stack is a container of elements with last in, first out access policy. Sometimes it also called LIFO.
The stack... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Case-sensitivity_of_identifiers | Case-sensitivity of identifiers | Three dogs (Are there three dogs or one dog?) is a code snippet used to illustrate the lettercase sensitivity of the programming language. For a case-sensitive language, the identifiers dog, Dog and DOG are all different and we should get the output:
The three dogs are named Benjamin, Samba and Bernie.
For a language... | #Arturo | Arturo | dog: "Benjamin"
Dog: "Samba"
DOG: "Bernie"
dogs: @[dog Dog DOG]
print ["The" size dogs "dog(s) are named" join.with:", " dogs] | Give a code snippet in #Arturo
Three dogs (Are there three dogs or one dog?) is a code snippet used to illustrate the lettercase sensitivity of the programming language. For a case-sensitive language, the identifiers dog, Dog and DOG are all different and we should get the output:
The three dogs are named Benjamin, S... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Dice_game_probabilities | Dice game probabilities | Two players have a set of dice each. The first player has nine dice with four faces each, with numbers one to four. The second player has six normal dice with six faces each, each face has the usual numbers from one to six.
They roll their dice and sum the totals of the faces. The player with the highest total wins (i... | #ooRexx | ooRexx | Numeric Digits 30
Call test '9 4 6 6'
Call test '5 10 6 7'
Exit
test:
Parse Arg w1 s1 w2 s2
p1.=0
p2.=0
Call pp 1,w1,s1,p1.,p2.
Call pp 2,w2,s2,p1.,p2.
p2low.=0
Do x=w1 To w1*s1
Do y=0 To x-1
p2low.x+=p2.y
End
End
pwin1=0
Do x=w1 To w1*s1
pwin1+=p1.x*p2low.x
End
Say 'Player 1 has' w1 'dice with' s1 'sid... | Give a code snippet in #ooRexx
Two players have a set of dice each. The first player has nine dice with four faces each, with numbers one to four. The second player has six normal dice with six faces each, each face has the usual numbers from one to six.
They roll their dice and sum the totals of the faces. The playe... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Minimum_positive_multiple_in_base_10_using_only_0_and_1 | Minimum positive multiple in base 10 using only 0 and 1 | Every positive integer has infinitely many base-10 multiples that only use the digits 0 and 1. The goal of this task is to find and display the minimum multiple that has this property.
This is simple to do, but can be challenging to do efficiently.
To avoid repeating long, unwieldy phrases, the operation "minimum pos... | #Kotlin | Kotlin | import java.math.BigInteger
fun main() {
for (n in testCases) {
val result = getA004290(n)
println("A004290($n) = $result = $n * ${result / n.toBigInteger()}")
}
}
private val testCases: List<Int>
get() {
val testCases: MutableList<Int> = ArrayList()
for (i in 1..10) {
... | Give a code snippet in #Kotlin
Every positive integer has infinitely many base-10 multiples that only use the digits 0 and 1. The goal of this task is to find and display the minimum multiple that has this property.
This is simple to do, but can be challenging to do efficiently.
To avoid repeating long, unwieldy phr... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Show_the_epoch | Show the epoch | Task
Choose popular date libraries used by your language and show the epoch those libraries use.
A demonstration is preferable (e.g. setting the internal representation of the date to 0 ms/ns/etc., or another way that will still show the epoch even if it is changed behind the scenes by the implementers), b... | #REXX | REXX | /*REXX program displays the number of days since the epoch for the DATE function (BIF). */
say ' today is: ' date() /*today's is format: mm MON YYYY */
days=date('Basedate') /*only the first char of option is used*/
say right(days, 40) " days since th... | Give a code snippet in #REXX
Task
Choose popular date libraries used by your language and show the epoch those libraries use.
A demonstration is preferable (e.g. setting the internal representation of the date to 0 ms/ns/etc., or another way that will still show the epoch even if it is changed behind the sc... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Increment_a_numerical_string | Increment a numerical string | Task
Increment a numerical string.
| #PHP | PHP | $s = "12345";
$s++; | Give a code snippet in #PHP
Task
Increment a numerical string.
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Set_consolidation | Set consolidation | Given two sets of items then if any item is common to any set then the result of applying consolidation to those sets is a set of sets whose contents is:
The two input sets if no common item exists between the two input sets of items.
The single set that is the union of the two input sets if they share a common item... | #JavaScript | JavaScript | (() => {
'use strict';
// consolidated :: Ord a => [Set a] -> [Set a]
const consolidated = xs => {
const go = (s, xs) =>
0 !== xs.length ? (() => {
const h = xs[0];
return 0 === intersection(h, s).size ? (
[h].concat(go(s, tail(xs)))
... | Give a code snippet in #JavaScript
Given two sets of items then if any item is common to any set then the result of applying consolidation to those sets is a set of sets whose contents is:
The two input sets if no common item exists between the two input sets of items.
The single set that is the union of the two in... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Letter_frequency | Letter frequency | Task
Open a text file and count the occurrences of each letter.
Some of these programs count all characters (including punctuation),
but some only count letters A to Z.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequen... | #Lambdatalk | Lambdatalk |
{script
// W.frequency is added to the lambdatalk dictionary via the {script ...} special form
LAMBDATALK.DICT['W.frequency'] = function() {
// 1) simply copied from the rosetta.org #Javascript entry
var frequency = function(txt) {
var cs = txt.split(''),
i = cs.length,
dct = {},... | Give a code snippet in #Lambdatalk
Task
Open a text file and count the occurrences of each letter.
Some of these programs count all characters (including punctuation),
but some only count letters A to Z.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Kernighans_large_earthquake_problem | Kernighans large earthquake problem | Brian Kernighan, in a lecture at the University of Nottingham, described a problem on which this task is based.
Problem
You are given a a data file of thousands of lines; each of three `whitespace` separated fields: a date, a one word name and the magnitude of the event.
Example lines from the file would be lines li... | #AWK | AWK | awk '$3 > 6' data.txt | Give a code snippet in #AWK
Brian Kernighan, in a lecture at the University of Nottingham, described a problem on which this task is based.
Problem
You are given a a data file of thousands of lines; each of three `whitespace` separated fields: a date, a one word name and the magnitude of the event.
Example lines fr... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Visualize_a_tree | Visualize a tree | A tree structure (i.e. a rooted, connected acyclic graph) is often used in programming.
It's often helpful to visually examine such a structure.
There are many ways to represent trees to a reader, such as:
indented text (à la unix tree command)
nested HTML tables
hierarchical GUI widgets
2D or ... | #Maple | Maple | T := GraphTheory:-Graph([1, 2, 3, 4, 5], {{1, 2}, {2, 3}, {2, 4}, {4, 5}}):
GraphTheory:-DrawGraph(T, style = tree); | Give a code snippet in #Maple
A tree structure (i.e. a rooted, connected acyclic graph) is often used in programming.
It's often helpful to visually examine such a structure.
There are many ways to represent trees to a reader, such as:
indented text (à la unix tree command)
nested HTML tables
hiera... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Euler_method | Euler method | Euler's method numerically approximates solutions of first-order ordinary differential equations (ODEs) with a given initial value. It is an explicit method for solving initial value problems (IVPs), as described in the wikipedia page.
The ODE has to be provided in the following form:
d
y
(
t
)
d
t
=
f... | #Haskell | Haskell | -- the solver
dsolveBy _ _ [] _ = error "empty solution interval"
dsolveBy method f mesh x0 = zip mesh results
where results = scanl (method f) x0 intervals
intervals = zip mesh (tail mesh) | Give a code snippet in #Haskell
Euler's method numerically approximates solutions of first-order ordinary differential equations (ODEs) with a given initial value. It is an explicit method for solving initial value problems (IVPs), as described in the wikipedia page.
The ODE has to be provided in the following form... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Loops/For_with_a_specified_step | Loops/For with a specified step |
Task
Demonstrate a for-loop where the step-value is greater than one.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downward for
Loops/For
Loops/For with a specified step
Loops/Foreach
Loops/Increment loop index within loop b... | #jq | jq | # If your version of jq does not have range/3, use this:
def range(m;n;step): range(0; ((n-m)/step) ) | m + (. * step);
range(2;9;2) | Give a code snippet in #jq
Task
Demonstrate a for-loop where the step-value is greater than one.
Related tasks
Loop over multiple arrays simultaneously
Loops/Break
Loops/Continue
Loops/Do-while
Loops/Downward for
Loops/For
Loops/For with a specified step
Loops/Foreach
Loops/Increm... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Mandelbrot_set | Mandelbrot set | Mandelbrot set
You are encouraged to solve this task according to the task description, using any language you may know.
Task
Generate and draw the Mandelbrot set.
Note that there are many algorithms to draw Mandelbrot set and there are many functions which generate it .
| #COBOL | COBOL | IDENTIFICATION DIVISION.
PROGRAM-ID. MANDELBROT-SET-PROGRAM.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 COMPLEX-ARITHMETIC.
05 X PIC S9V9(9).
05 Y PIC S9V9(9).
05 X-A PIC S9V9(6).
05 X-B PIC S9V9(6).
05 Y-A PIC S9V9(6).
05 X-A-SQUA... | Give a code snippet in #COBOL
Mandelbrot set
You are encouraged to solve this task according to the task description, using any language you may know.
Task
Generate and draw the Mandelbrot set.
Note that there are many algorithms to draw Mandelbrot set and there are many functions which generate it .
| christopher/rosetta-code | |
http://rosettacode.org/wiki/Empty_string | Empty string | Languages may have features for dealing specifically with empty strings
(those containing no characters).
Task
Demonstrate how to assign an empty string to a variable.
Demonstrate how to check that a string is empty.
Demonstrate how to check that a string is not empty.
Other tasks related to string oper... | #APL | APL |
⍝⍝ Assign empty string to A
A ← ''
0 = ⍴∊ A
1
~0 = ⍴∊ A
0
| Give a code snippet in #APL
Languages may have features for dealing specifically with empty strings
(those containing no characters).
Task
Demonstrate how to assign an empty string to a variable.
Demonstrate how to check that a string is empty.
Demonstrate how to check that a string is not empty.
Other... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Doubly-linked_list/Traversal | Doubly-linked list/Traversal | Traverse from the beginning of a doubly-linked list to the end, and from the end to the beginning.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Def... | #FreeBASIC | FreeBASIC | Dim As Integer i, MiLista()
For i = 0 To Int(Rnd * 100)+25
Redim Preserve MiLista(i)
MiLista(i) = Rnd * 314
Next
'Tour from the beginning
For i = Lbound(MiLista) To Ubound(MiLista)
Print MiLista(i)
Next i
Print
'Travel from the end
For i = Ubound(MiLista) To Lbound(MiLista) Step -1
Print MiLista... | Give a code snippet in #FreeBASIC
Traverse from the beginning of a doubly-linked list to the end, and from the end to the beginning.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Eleme... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Arithmetic/Integer | Arithmetic/Integer |
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
Concatenation |
Interpolation |... | #COBOL | COBOL | IDENTIFICATION DIVISION.
PROGRAM-ID. Int-Arithmetic.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 A PIC S9(10).
01 B PIC S9(10).
01 Result PIC S9(10).
PROCEDURE DIVISION.
DISPLAY "First number: " WITH NO ADVANCING
ACCEPT A
... | Give a code snippet in #COBOL
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
... | christopher/rosetta-code | |
http://rosettacode.org/wiki/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 ... | #Clojure | Clojure | (defn dot-product [& matrix]
{:pre [(apply == (map count matrix))]}
(apply + (apply map * matrix)))
(defn dot-product2 [x y]
(->> (interleave x y)
(partition 2 2)
(map #(apply * %))
(reduce +)))
(defn dot-product3
"Dot product of vectors. Tested on version 1.8.0."
[v1 v2]
{:pre [(= (cou... | Give a code snippet in #Clojure
Task
Create a function/use an in-built function, to compute the dot product, also known as the scalar product of two vectors.
If possible, make the vectors of arbitrary length.
As an example, compute the dot product of the vectors:
[1, 3, -5] and
[4, -2, ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Nonoblock | Nonoblock | Nonoblock is a chip off the old Nonogram puzzle.
Given
The number of cells in a row.
The size of each, (space separated), connected block of cells to fit in the row, in left-to right order.
Task
show all possible positions.
show the number of positions of the blocks for the following cases within the row. ... | #M2000_Interpreter | M2000 Interpreter |
Module NonoBlock {
Form 80,40
Flush
Print "Nonoblock"
Data 5, (2, 1)
Data 5, (,)
Data 10, (8,)
Data 15, (2,3,2,3)
Data 5, (2,3)
Def BLen(a$)=(Len(a$)-1)/2
Function UseLetter(arr) {
Dim Base 0, Res$(Len(arr))
Link Res$() to Res()
... | Give a code snippet in #M2000_Interpreter
Nonoblock is a chip off the old Nonogram puzzle.
Given
The number of cells in a row.
The size of each, (space separated), connected block of cells to fit in the row, in left-to right order.
Task
show all possible positions.
show the number of positions of the bloc... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Fivenum | Fivenum | Many big data or scientific programs use boxplots to show distributions of data. In addition, sometimes saving large arrays for boxplots can be impractical and use extreme amounts of RAM. It can be useful to save large arrays as arrays with five numbers to save memory.
For example, the R programming language i... | #Stata | Stata | clear
set seed 17760704
qui set obs 10000
gen x=rnormal() | Give a code snippet in #Stata
Many big data or scientific programs use boxplots to show distributions of data. In addition, sometimes saving large arrays for boxplots can be impractical and use extreme amounts of RAM. It can be useful to save large arrays as arrays with five numbers to save memory.
For example, t... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Matrix_chain_multiplication | Matrix chain multiplication | Problem
Using the most straightfoward algorithm (which we assume here), computing the product of two matrices of dimensions (n1,n2) and (n2,n3) requires n1*n2*n3 FMA operations. The number of operations required to compute the product of matrices A1, A2... An depends on the order of matrix multiplications, hence on whe... | #Go | Go | package main
import "fmt"
// PrintMatrixChainOrder prints the optimal order for chain
// multiplying matrices.
// Matrix A[i] has dimensions dims[i-1]×dims[i].
func PrintMatrixChainOrder(dims []int) {
n := len(dims) - 1
m, s := newSquareMatrices(n)
// m[i,j] will be minimum number of scalar multiplactions
// ... | Give a code snippet in #Go
Problem
Using the most straightfoward algorithm (which we assume here), computing the product of two matrices of dimensions (n1,n2) and (n2,n3) requires n1*n2*n3 FMA operations. The number of operations required to compute the product of matrices A1, A2... An depends on the order of matrix m... | christopher/rosetta-code | |
http://rosettacode.org/wiki/SEDOLs | SEDOLs | Task
For each number list of 6-digit SEDOLs, calculate and append the checksum digit.
That is, given this input:
710889
B0YBKJ
406566
B0YBLH
228276
B0YBKL
557910
B0YBKR
585284
B0YBKT
B00030
Produce this output:
7108899
B0YBKJ7
4065663
B0YBLH2
2282765
B0YBKL9
5579107
B0YBKR5
5852842
B0YBKT7
B000300
Extra credit
... | #Excel | Excel | SEDOLCHECKSUM
=LAMBDA(s,
IF(6 = LEN(s),
LET(
cs, MID(s, SEQUENCE(1, 6, 1, 1), 1),
isVowel, LAMBDA(c,
ELEM(c)({"A","E","I","O","U"})
),
sedolValue, LAMBDA(c,
LET(
ic, CODE(c),
IF(65 > ic,
... | Give a code snippet in #Excel
Task
For each number list of 6-digit SEDOLs, calculate and append the checksum digit.
That is, given this input:
710889
B0YBKJ
406566
B0YBLH
228276
B0YBKL
557910
B0YBKR
585284
B0YBKT
B00030
Produce this output:
7108899
B0YBKJ7
4065663
B0YBLH2
2282765
B0YBKL9
5579107
B0YBKR5
5852842... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Zebra_puzzle | Zebra puzzle | Zebra puzzle
You are encouraged to solve this task according to the task description, using any language you may know.
The Zebra puzzle, a.k.a. Einstein's Riddle,
is a logic puzzle which is to be solved programmatically.
It has several variants, one of them this:
There are five houses.
The English man lives ... | #Vlang | Vlang | type HouseSet = []House
struct House {
n Nationality
c Colour
a Animal
d Drink
s Smoke
}
// Define the possible values
enum Nationality {
english = 0
swede
dane
norwegian
german
}
enum Colour {
red = 0
green
white
yellow
blue
}
enum Animal {
dog = 0
... | Give a code snippet in #Vlang
Zebra puzzle
You are encouraged to solve this task according to the task description, using any language you may know.
The Zebra puzzle, a.k.a. Einstein's Riddle,
is a logic puzzle which is to be solved programmatically.
It has several variants, one of them this:
There are five ho... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Wilson_primes_of_order_n | Wilson primes of order n | Definition
A Wilson prime of order n is a prime number p such that p2 exactly divides:
(n − 1)! × (p − n)! − (− 1)n
If n is 1, the latter formula reduces to the more familiar: (p - n)! + 1 where the only known examples for p are 5, 13, and 563.
Task
Calculate and show on thi... | #FreeBASIC | FreeBASIC | #include "isprime.bas"
function is_wilson( n as uinteger, p as uinteger ) as boolean
'tests if p^2 divides (n-1)!(p-n)! - (-1)^n
'does NOT test the primality of p; do that first before you call this!
'using mods no big nums are required
if p<n then return false
dim as uinteger prod = 1, i, p2 = p^... | Give a code snippet in #FreeBASIC
Definition
A Wilson prime of order n is a prime number p such that p2 exactly divides:
(n − 1)! × (p − n)! − (− 1)n
If n is 1, the latter formula reduces to the more familiar: (p - n)! + 1 where the only known examples for p are 5, 13, and 563... | 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 ... | #Swift | Swift | func dot(v1: [Double], v2: [Double]) -> Double {
return reduce(lazy(zip(v1, v2)).map(*), 0, +)
}
println(dot([1, 3, -5], [4, -2, -1])) | Give a code snippet in #Swift
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/Compiler/AST_interpreter | Compiler/AST interpreter | An AST interpreter interprets an Abstract Syntax Tree (AST)
produced by a Syntax Analyzer.
Task[edit]
Take the AST output from the Syntax analyzer task, and interpret it as appropriate.
Refer to the Syntax analyzer task for details of the AST.
Loading the AST from the syntax analyzer is as simple as (pseudo code)
de... | #ALGOL_W | ALGOL W | begin % AST interpreter %
% parse tree nodes %
record node( integer type
; reference(node) left, right
; integer iValue % nString/nIndentifier number or nInteger value %
);
integer nIdentifier, nString, nInteger, nSequence, nIf, nPrtc, nPrts... | Give a code snippet in #ALGOL_W
An AST interpreter interprets an Abstract Syntax Tree (AST)
produced by a Syntax Analyzer.
Task[edit]
Take the AST output from the Syntax analyzer task, and interpret it as appropriate.
Refer to the Syntax analyzer task for details of the AST.
Loading the AST from the syntax analyzer ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Vigen%C3%A8re_cipher | Vigenère cipher | Task
Implement a Vigenère cypher, both encryption and decryption.
The program should handle keys and text of unequal length,
and should capitalize everything and discard non-alphabetic characters.
(If your program handles non-alphabetic characters in another way,
make a note of it.)
Related tasks
Caesar ... | #Clojure | Clojure | (ns org.rosettacode.clojure.vigenere
(:require [clojure.string :as string]))
; convert letter to offset from \A
(defn to-num [char] (- (int char) (int \A)))
; convert number to letter, treating it as modulo 26 offset from \A
(defn from-num [num] (char (+ (mod num 26) (int \A))))
; Convert a string to a sequence... | Give a code snippet in #Clojure
Task
Implement a Vigenère cypher, both encryption and decryption.
The program should handle keys and text of unequal length,
and should capitalize everything and discard non-alphabetic characters.
(If your program handles non-alphabetic characters in another way,
make a note of ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Count_in_octal | Count in octal | Task
Produce a sequential count in octal, starting at zero, and using an increment of a one for each consecutive number.
Each number should appear on a single line, and the program should count until terminated, or until the maximum value of the numeric type in use is reached.
Related task
Integer sequ... | #Emacs_Lisp | Emacs Lisp | (dotimes (i most-positive-fixnum) ;; starting from 0
(message "%o" i)) | Give a code snippet in #Emacs_Lisp
Task
Produce a sequential count in octal, starting at zero, and using an increment of a one for each consecutive number.
Each number should appear on a single line, and the program should count until terminated, or until the maximum value of the numeric type in use is reach... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Array_length | Array length | Task
Determine the amount of elements in an array.
As an example use an array holding the strings 'apple' and 'orange'.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I befo... | #Phix | Phix | constant fruits = {"apple","orange"}
?length(fruits)
| Give a code snippet in #Phix
Task
Determine the amount of elements in an array.
As an example use an array holding the strings 'apple' and 'orange'.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter freque... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Forward_difference | Forward difference | Task
Provide code that produces a list of numbers which is the nth order forward difference, given a non-negative integer (specifying the order) and a list of numbers.
The first-order forward difference of a list of numbers A is a new list B, where Bn = An+1 - An.
List B should have one fewer elem... | #Logo | Logo | to fwd.diff :l
if empty? :l [output []]
if empty? bf :l [output []]
output fput (first bf :l)-(first :l) fwd.diff bf :l
end
to nth.fwd.diff :n :l
if :n = 0 [output :l]
output nth.fwd.diff :n-1 fwd.diff :l
end
show nth.fwd.diff 9 [90 47 58 29 22 32 55 5 55 73]
[-2921] | Give a code snippet in #Logo
Task
Provide code that produces a list of numbers which is the nth order forward difference, given a non-negative integer (specifying the order) and a list of numbers.
The first-order forward difference of a list of numbers A is a new list B, where Bn = An+1 - An.
List ... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Compiler/AST_interpreter | Compiler/AST interpreter | An AST interpreter interprets an Abstract Syntax Tree (AST)
produced by a Syntax Analyzer.
Task[edit]
Take the AST output from the Syntax analyzer task, and interpret it as appropriate.
Refer to the Syntax analyzer task for details of the AST.
Loading the AST from the syntax analyzer is as simple as (pseudo code)
de... | #Go | Go | package main
import (
"bufio"
"fmt"
"log"
"os"
"strconv"
"strings"
)
type NodeType int
const (
ndIdent NodeType = iota
ndString
ndInteger
ndSequence
ndIf
ndPrtc
ndPrts
ndPrti
ndWhile
ndAssign
ndNegate
ndNot
ndMul
ndDiv
ndMod
n... | Give a code snippet in #Go
An AST interpreter interprets an Abstract Syntax Tree (AST)
produced by a Syntax Analyzer.
Task[edit]
Take the AST output from the Syntax analyzer task, and interpret it as appropriate.
Refer to the Syntax analyzer task for details of the AST.
Loading the AST from the syntax analyzer is as... | christopher/rosetta-code | |
http://rosettacode.org/wiki/Sorting_algorithms/Stooge_sort | Sorting algorithms/Stooge sort |
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
... | #Java | Java | import java.util.Arrays;
public class Stooge {
public static void main(String[] args) {
int[] nums = {1, 4, 5, 3, -6, 3, 7, 10, -2, -5};
stoogeSort(nums);
System.out.println(Arrays.toString(nums));
}
public static void stoogeSort(int[] L) {
stoogeSort(L, 0, L.length - 1);... | 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/Draw_a_sphere | Draw a sphere | Task
Draw a sphere.
The sphere can be represented graphically, or in ASCII art, depending on the language capabilities.
Either static or rotational projection is acceptable for this task.
Related tasks
draw a cuboid
draw a rotating cube
write language name in 3D ASCII
draw a Deathstar
| #Mathematica_.2F_Wolfram_Language | Mathematica / Wolfram Language | Graphics3D[Sphere[{0,0,0},1]] | Give a code snippet in #Mathematica_.2F_Wolfram_Language
Task
Draw a sphere.
The sphere can be represented graphically, or in ASCII art, depending on the language capabilities.
Either static or rotational projection is acceptable for this task.
Related tasks
draw a cuboid
draw a rotating cube
write language ... | christopher/rosetta-code |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.