task_url stringlengths 30 116 | task_name stringlengths 2 86 | task_description stringlengths 0 14.4k | language_url stringlengths 2 53 | language_name stringlengths 1 52 | code stringlengths 0 61.9k |
|---|---|---|---|---|---|
http://rosettacode.org/wiki/Average_loop_length | Average loop length | Let f be a uniformly-randomly chosen mapping from the numbers 1..N to the numbers 1..N (note: not necessarily a permutation of 1..N; the mapping could produce a number in more than one way or not at all). At some point, the sequence 1, f(1), f(f(1))... will contain a repetition, a number that occurring for the second t... | #F.23 | F# | open System
let gamma z =
let lanczosCoefficients = [76.18009172947146;-86.50532032941677;24.01409824083091;-1.231739572450155;0.1208650973866179e-2;-0.5395239384953e-5]
let rec sumCoefficients acc i coefficients =
match coefficients with
| [] -> acc
| h::t -> sumCoefficients (acc +... |
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... | #PowerShell | PowerShell |
#This version allows a user to enter numbers one at a time to figure this into the SMA calculations
$inputs = @() #Create an array to hold all inputs as they are entered.
$period1 = 3 #Define the periods you want to utilize
$period2 = 5
Write-host "Enter numbers to observe their moving averages." -ForegroundColor... |
http://rosettacode.org/wiki/Attractive_numbers | Attractive numbers | A number is an attractive number if the number of its prime factors (whether distinct or not) is also prime.
Example
The number 20, whose prime decomposition is 2 × 2 × 5, is an attractive number because the number of its prime factors (3) is also prime.
Task
Show sequence items up to 120.... | #CLU | CLU | sieve = proc (max: int) returns (array[bool])
prime: array[bool] := array[bool]$fill(1,max,true)
prime[1] := false
for p: int in int$from_to(2, max/2) do
if prime[p] then
for c: int in int$from_to_by(p*p, max, p) do
prime[c] := false
end
end
end
... |
http://rosettacode.org/wiki/Attractive_numbers | Attractive numbers | A number is an attractive number if the number of its prime factors (whether distinct or not) is also prime.
Example
The number 20, whose prime decomposition is 2 × 2 × 5, is an attractive number because the number of its prime factors (3) is also prime.
Task
Show sequence items up to 120.... | #COBOL | COBOL | IDENTIFICATION DIVISION.
PROGRAM-ID. ATTRACTIVE-NUMBERS.
DATA DIVISION.
WORKING-STORAGE SECTION.
77 MAXIMUM PIC 999 VALUE 120.
01 SIEVE-DATA VALUE SPACES.
03 MARKER PIC X OCCURS 120 TIMES.
88 PRIME VALUE SPACE.
03 SIEVE-... |
http://rosettacode.org/wiki/Averages/Mean_time_of_day | Averages/Mean time of day | Task[edit]
A particular activity of bats occurs at these times of the day:
23:00:17, 23:40:20, 00:12:45, 00:17:19
Using the idea that there are twenty-four hours in a day,
which is analogous to there being 360 degrees in a circle,
map times of day to and from angles;
and using the ideas of Averages/Mean angle
compute ... | #Haskell | Haskell | import Data.Complex (cis, phase)
import Data.List.Split (splitOn)
import Text.Printf (printf)
timeToRadians :: String -> Float
timeToRadians time =
let hours:minutes:seconds:_ = splitOn ":" time
s = fromIntegral (read seconds :: Int)
m = fromIntegral (read minutes :: Int)
... |
http://rosettacode.org/wiki/AVL_tree | AVL tree |
This page uses content from Wikipedia. The original article was at AVL tree. 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 computer science, an AVL tree is a self-balancing binary search tree.... | #J | J | insert=: {{
X=.1 {::2{.x,x NB. middle element of x (don't fail on empty x)
Y=.1 {::2{.y,y NB. middle element of y (don't fail on empty y)
select.#y
case.0 do.x NB. y is an empty node
case.1 do. NB. y is a leaf node
select.*Y-X
case._1 do.a:,y;<x
case. 0 do.y
case. 1 do... |
http://rosettacode.org/wiki/Averages/Mean_angle | Averages/Mean angle | When calculating the average or mean of an angle one has to take into account how angles wrap around so that any angle in degrees plus any integer multiple of 360 degrees is a measure of the same angle.
If one wanted an average direction of the wind over two readings where the first reading was of 350 degrees and the ... | #FreeBASIC | FreeBASIC |
' FB 1.05.0 Win64
Const PI As Double = 3.1415926535897932
Function MeanAngle(angles() As Double) As Double
Dim As Integer length = Ubound(angles) - Lbound(angles) + 1
Dim As Double sinSum = 0.0
Dim As Double cosSum = 0.0
For i As Integer = LBound(angles) To UBound(angles)
sinSum += Sin(angles(i) * PI ... |
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 ... | #C.2B.2B | C++ | #include <algorithm>
// inputs must be random-access iterators of doubles
// Note: this function modifies the input range
template <typename Iterator>
double median(Iterator begin, Iterator end) {
// this is middle for odd-length, and "upper-middle" for even length
Iterator middle = begin + (end - begin) / 2;
... |
http://rosettacode.org/wiki/Averages/Pythagorean_means | Averages/Pythagorean means | Task[edit]
Compute all three of the Pythagorean means of the set of integers 1 through 10 (inclusive).
Show that
A
(
x
1
,
…
,
x
n
)
≥
G
(
x
1
,
…
,
x
n
)
≥
H
(
x
1
,
…
,
x
n
)
{\displaystyle A(x_{1},\ldots ,x_{n})\geq G(x_{1},\ldots ,x_{n})\geq H(x_{1},\ldots ,x_{n})}
for this set of p... | #FunL | FunL | import lists.zip
def
mean( s, 0 ) = product( s )^(1/s.length())
mean( s, p ) = (1/s.length() sum( x^p | x <- s ))^(1/p)
def
monotone( [_], _ ) = true
monotone( a1:a2:as, p ) = p( a1, a2 ) and monotone( a2:as, p )
means = [mean( 1..10, m ) | m <- [1, 0, -1]]
for (m, l) <- zip( means, ['Arithmetic', 'Geom... |
http://rosettacode.org/wiki/Balanced_ternary | Balanced ternary | Balanced ternary is a way of representing numbers. Unlike the prevailing binary representation, a balanced ternary integer is in base 3, and each digit can have the values 1, 0, or −1.
Examples
Decimal 11 = 32 + 31 − 30, thus it can be written as "++−"
Decimal 6 = 32 − 31 + 0 × 30, thus it can be written as "+−0"
... | #Julia | Julia | struct BalancedTernary <: Signed
digits::Vector{Int8}
end
BalancedTernary() = zero(BalancedTernary)
BalancedTernary(n) = convert(BalancedTernary, n)
const sgn2chr = Dict{Int8,Char}(-1 => '-', 0 => '0', +1 => '+')
Base.show(io::IO, bt::BalancedTernary) = print(io, join(sgn2chr[x] for x in reverse(bt.digits)))
Base... |
http://rosettacode.org/wiki/Babbage_problem | Babbage problem |
Charles Babbage, looking ahead to the sorts of problems his Analytical Engine would be able to solve, gave this example:
What is the smallest positive integer whose square ends in the digits 269,696?
— Babbage, letter to Lord Bowden, 1837; see Hollingdale and Tootill, Electronic Computers, second edition, 1970, p.... | #Phix | Phix | with javascript_semantics
for i=2 to 99736 by 2 do
if remainder(i*i,1000000)=269696 then ?i exit end if
end for
|
http://rosettacode.org/wiki/Approximate_equality | Approximate equality | Sometimes, when testing whether the solution to a task (for example, here on Rosetta Code) is correct, the
difference in floating point calculations between different language implementations becomes significant.
For example, a difference between 32 bit and 64 bit floating point calculations may appear by
about the 8t... | #C | C | #include <math.h>
#include <stdbool.h>
#include <stdio.h>
bool approxEquals(double value, double other, double epsilon) {
return fabs(value - other) < epsilon;
}
void test(double a, double b) {
double epsilon = 1e-18;
printf("%f, %f => %d\n", a, b, approxEquals(a, b, epsilon));
}
int main() {
test... |
http://rosettacode.org/wiki/Approximate_equality | Approximate equality | Sometimes, when testing whether the solution to a task (for example, here on Rosetta Code) is correct, the
difference in floating point calculations between different language implementations becomes significant.
For example, a difference between 32 bit and 64 bit floating point calculations may appear by
about the 8t... | #C.23 | C# | using System;
public static class Program
{
public static void Main() {
Test(100000000000000.01, 100000000000000.011);
Test(100.01, 100.011);
Test(10000000000000.001 / 10000.0, 1000000000.0000001000);
Test(0.001, 0.0010000001);
Test(0.000000000000000000000101, 0.0);
... |
http://rosettacode.org/wiki/Balanced_brackets | Balanced brackets | Task:
Generate a string with N opening brackets [ and with N closing brackets ], in some arbitrary order.
Determine whether the generated string is balanced; that is, whether it consists entirely of pairs of opening/closing brackets (in that order), none of which mis-nest.
Examples
(empty) ... | #Brat | Brat | string.prototype.balanced? = {
brackets = []
balanced = true
my.dice.each_while { c |
true? c == "["
{ brackets << c }
{ true? c == "]"
{ last = brackets.pop
false? last == "["
{ balanced = false }
}
}
balanced
}
true? brackets.empty?
{ b... |
http://rosettacode.org/wiki/Atomic_updates | Atomic updates |
Task
Define a data type consisting of a fixed number of 'buckets', each containing a nonnegative integer value, which supports operations to:
get the current value of any bucket
remove a specified amount from one specified bucket and add it to another, preserving the total of all bucket values, and clamping the t... | #C.23 | C# | - Changed to using object locks and Montor.Enter rather than Mutexes. This allows use of the cleaner "lock" statement, and also has lower runtime overhead for in process locks
- The previous implementation tracked a "swapped" state - which seems a harder way to tackle the problem. You need to acquire the locks in th... |
http://rosettacode.org/wiki/Atomic_updates | Atomic updates |
Task
Define a data type consisting of a fixed number of 'buckets', each containing a nonnegative integer value, which supports operations to:
get the current value of any bucket
remove a specified amount from one specified bucket and add it to another, preserving the total of all bucket values, and clamping the t... | #C.2B.2B | C++ | #include <algorithm>
#include <array>
#include <chrono>
#include <iomanip>
#include <iostream>
#include <mutex>
#include <random>
#include <thread>
using namespace std;
constexpr int bucket_count = 15;
void equalizer(array<int, bucket_count>& buckets,
array<mutex, bucket_count>& bucket_mutex) {
... |
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.
| #Axe | Axe | A=42??Returnʳ |
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.
| #BaCon | BaCon | ' Assertions
answer = assertion(42)
PRINT "The ultimate answer is indeed ", answer
PRINT "Now, expect a failure, unless NDEBUG defined at compile time"
answer = assertion(41)
PRINT answer
END
' Ensure the given number is the ultimate answer
FUNCTION assertion(NUMBER i)
' BaCon can easily be intimately integra... |
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.
| #BASIC256 | BASIC256 |
subroutine assert (condition, message)
if not condition then print "ASSERTION FAIED: ";message: throwerror 1
end subroutine
call assert(1+1=2, "but I don't expect this assertion to fail"): rem Does not throw an error
rem call assert(1+1=3, "and rightly so"): rem Throws an error
|
http://rosettacode.org/wiki/Averages/Mode | Averages/Mode | Task[edit]
Write a program to find the mode value of a collection.
The case where the collection is empty may be ignored. Care must be taken to handle the case where the mode is non-unique.
If it is not appropriate or possible to support a general collection, use a vector (array), if possible. If it is not appropriat... | #J | J | mode=: ~. #~ ( = >./ )@( #/.~ ) |
http://rosettacode.org/wiki/Averages/Mode | Averages/Mode | Task[edit]
Write a program to find the mode value of a collection.
The case where the collection is empty may be ignored. Care must be taken to handle the case where the mode is non-unique.
If it is not appropriate or possible to support a general collection, use a vector (array), if possible. If it is not appropriat... | #Java | Java | import java.util.*;
public class Mode {
public static <T> List<T> mode(List<? extends T> coll) {
Map<T, Integer> seen = new HashMap<T, Integer>();
int max = 0;
List<T> maxElems = new ArrayList<T>();
for (T value : coll) {
if (seen.containsKey(value))
see... |
http://rosettacode.org/wiki/Associative_array/Iteration | Associative array/Iteration | Show how to iterate over the key-value pairs of an associative array, and print each pair out.
Also show how to iterate just over the keys, or the values, if there is a separate way to do that in your language.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked ... | #8th | 8th |
{"one": 1, "two": "bad"}
( swap . space . cr )
m:each
|
http://rosettacode.org/wiki/Associative_array/Iteration | Associative array/Iteration | Show how to iterate over the key-value pairs of an associative array, and print each pair out.
Also show how to iterate just over the keys, or the values, if there is a separate way to do that in your language.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked ... | #Ada | Ada | with Ada.Text_IO; use Ada.Text_IO;
with Ada.Containers.Indefinite_Ordered_Maps;
procedure Test_Iteration is
package String_Maps is
new Ada.Containers.Indefinite_Ordered_Maps (String, Integer);
use String_Maps;
A : Map;
Index : Cursor;
begin
A.Insert ("hello", 1);
A.Insert ("world", 2);
... |
http://rosettacode.org/wiki/Apply_a_digital_filter_(direct_form_II_transposed) | Apply a digital filter (direct form II transposed) | Digital filters are used to apply a mathematical operation to a sampled signal. One of the common formulations is the "direct form II transposed" which can represent both infinite impulse response (IIR) and finite impulse response (FIR) filters, as well as being more numerically stable than other forms. [1]
Task
Filt... | #Ada | Ada | with Ada.Text_IO;
procedure Apply_Filter is
generic
type Num is digits <>;
type Num_Array is array (Natural range <>) of Num;
A : Num_Array;
B : Num_Array;
package Direct_Form_II_Transposed is
pragma Assert (A'First = 0 and B'First = 0);
pragma Assert (A'Last = B'Last);
... |
http://rosettacode.org/wiki/Averages/Arithmetic_mean | Averages/Arithmetic mean | Task[edit]
Write a program to find the mean (arithmetic average) of a numeric vector.
In case of a zero-length input, since the mean of an empty set of numbers is ill-defined, the program may choose to behave in any way it deems appropriate, though if the programming language has an established convention for conveyin... | #Arturo | Arturo | arr: [1 2 3 4 5 6 7]
print average arr |
http://rosettacode.org/wiki/Averages/Arithmetic_mean | Averages/Arithmetic mean | Task[edit]
Write a program to find the mean (arithmetic average) of a numeric vector.
In case of a zero-length input, since the mean of an empty set of numbers is ill-defined, the program may choose to behave in any way it deems appropriate, though if the programming language has an established convention for conveyin... | #Astro | Astro | mean([1, 2, 3])
mean(1..10)
mean([])
|
http://rosettacode.org/wiki/Associative_array/Merging | Associative array/Merging | Task
Define two associative arrays, where one represents the following "base" data:
Key
Value
"name"
"Rocket Skates"
"price"
12.75
"color"
"yellow"
And the other represents "update" data:
Key
Value
"price"
15.25
"color"
"red"
"year"
1974
Merge these into a new associativ... | #Dart | Dart |
main() {
var base = {
'name': 'Rocket Skates',
'price': 12.75,
'color': 'yellow'
};
var newData = {
'price': 15.25,
'color': 'red',
'year': 1974
};
var updated = Map.from( base ) // create new Map from base
..addAll( newData ); // use cascade operator to add all new data
assert( base.to... |
http://rosettacode.org/wiki/Associative_array/Merging | Associative array/Merging | Task
Define two associative arrays, where one represents the following "base" data:
Key
Value
"name"
"Rocket Skates"
"price"
12.75
"color"
"yellow"
And the other represents "update" data:
Key
Value
"price"
15.25
"color"
"red"
"year"
1974
Merge these into a new associativ... | #Delphi | Delphi |
program Associative_arrayMerging;
{$APPTYPE CONSOLE}
uses
System.Generics.Collections;
type
TData = TDictionary<string, Variant>;
var
baseData, updateData, mergedData: TData;
entry: string;
begin
baseData := TData.Create();
baseData.Add('name', 'Rocket Skates');
baseData.Add('price', 12.75);
... |
http://rosettacode.org/wiki/Average_loop_length | Average loop length | Let f be a uniformly-randomly chosen mapping from the numbers 1..N to the numbers 1..N (note: not necessarily a permutation of 1..N; the mapping could produce a number in more than one way or not at all). At some point, the sequence 1, f(1), f(f(1))... will contain a repetition, a number that occurring for the second t... | #Factor | Factor | USING: formatting fry io kernel locals math math.factorials
math.functions math.ranges random sequences ;
: (analytical) ( m n -- x )
[ drop factorial ] [ ^ /f ] [ - factorial / ] 2tri ;
: analytical ( n -- x )
dup [1,b] [ (analytical) ] with map-sum ;
: loop-length ( n -- x )
[ 0 0 1 [ 2dup bitand ze... |
http://rosettacode.org/wiki/Average_loop_length | Average loop length | Let f be a uniformly-randomly chosen mapping from the numbers 1..N to the numbers 1..N (note: not necessarily a permutation of 1..N; the mapping could produce a number in more than one way or not at all). At some point, the sequence 1, f(1), f(f(1))... will contain a repetition, a number that occurring for the second t... | #FreeBASIC | FreeBASIC | Const max_N = 20, max_ciclos = 1000000
Function Factorial(Byval N As Integer) As Double
Dim As Double d: d = 1
If N = 0 Then Factorial = 1: Exit Function
While (N > 1)
d *= N
N -= 1
Wend
Factorial = d
End Function
Function Analytical(N As Integer) As Double
Dim As Double i, s... |
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... | #PureBasic | PureBasic | Procedure.d SMA(Number, Period=0)
Static P
Static NewList L()
Protected Sum=0
If Period<>0
P=Period
EndIf
LastElement(L())
AddElement(L())
L()=Number
While ListSize(L())>P
FirstElement(L())
DeleteElement(L(),1)
Wend
ForEach L()
sum+L()
Next
ProcedureReturn sum/ListSize(L())
En... |
http://rosettacode.org/wiki/Attractive_numbers | Attractive numbers | A number is an attractive number if the number of its prime factors (whether distinct or not) is also prime.
Example
The number 20, whose prime decomposition is 2 × 2 × 5, is an attractive number because the number of its prime factors (3) is also prime.
Task
Show sequence items up to 120.... | #Comal | Comal | 0010 FUNC factors#(n#) CLOSED
0020 count#:=0
0030 WHILE n# MOD 2=0 DO n#:=n# DIV 2;count#:+1
0040 fac#:=3
0050 WHILE fac#<=n# DO
0060 WHILE n# MOD fac#=0 DO n#:=n# DIV fac#;count#:+1
0070 fac#:+2
0080 ENDWHILE
0090 RETURN count#
0100 ENDFUNC factors#
0110 //
0120 ZONE 4
0130 seen#:=0
0140 FOR i#:=2 ... |
http://rosettacode.org/wiki/Attractive_numbers | Attractive numbers | A number is an attractive number if the number of its prime factors (whether distinct or not) is also prime.
Example
The number 20, whose prime decomposition is 2 × 2 × 5, is an attractive number because the number of its prime factors (3) is also prime.
Task
Show sequence items up to 120.... | #Common_Lisp | Common Lisp |
(defun attractivep (n)
(primep (length (factors n))) )
; For primality testing we can use different methods, but since we have to define factors that's what we'll use
(defun primep (n)
(= (length (factors n)) 1) )
(defun factors (n)
"Return a list of factors of N."
(when (> n 1)
(loop with max-d = (is... |
http://rosettacode.org/wiki/Averages/Mean_time_of_day | Averages/Mean time of day | Task[edit]
A particular activity of bats occurs at these times of the day:
23:00:17, 23:40:20, 00:12:45, 00:17:19
Using the idea that there are twenty-four hours in a day,
which is analogous to there being 360 degrees in a circle,
map times of day to and from angles;
and using the ideas of Averages/Mean angle
compute ... | #Icon_and_Unicon | Icon and Unicon | procedure main(A)
every put(B := [], ct2a(!A))
write(ca2t(meanAngle(B)))
end
procedure ct2a(t)
t ? {s := ((1(move(2),move(1))*60 + 1(move(2),move(1)))*60 + move(2))}
return (360.0/86400.0) * s
end
procedure ca2t(a)
while a < 0 do a +:= 360.0
t := integer((86400.0/360.0)*a + 0.5)
s := lef... |
http://rosettacode.org/wiki/Averages/Mean_time_of_day | Averages/Mean time of day | Task[edit]
A particular activity of bats occurs at these times of the day:
23:00:17, 23:40:20, 00:12:45, 00:17:19
Using the idea that there are twenty-four hours in a day,
which is analogous to there being 360 degrees in a circle,
map times of day to and from angles;
and using the ideas of Averages/Mean angle
compute ... | #J | J | require 'types/datetime'
parseTimes=: ([: _&".;._2 ,&':');._2
secsFromTime=: 24 60 60 #. ] NB. convert from time to seconds
rft=: 2r86400p1 * secsFromTime NB. convert from time to radians
meanTime=: 'hh:mm:ss' fmtTime [: secsFromTime [: avgAngleR&.rft parseTimes |
http://rosettacode.org/wiki/AVL_tree | AVL tree |
This page uses content from Wikipedia. The original article was at AVL tree. 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 computer science, an AVL tree is a self-balancing binary search tree.... | #Java | Java | public class AVLtree {
private Node root;
private static class Node {
private int key;
private int balance;
private int height;
private Node left;
private Node right;
private Node parent;
Node(int key, Node parent) {
this.key = key;
... |
http://rosettacode.org/wiki/Averages/Mean_angle | Averages/Mean angle | When calculating the average or mean of an angle one has to take into account how angles wrap around so that any angle in degrees plus any integer multiple of 360 degrees is a measure of the same angle.
If one wanted an average direction of the wind over two readings where the first reading was of 350 degrees and the ... | #Go | Go | package main
import (
"fmt"
"math"
"math/cmplx"
)
func deg2rad(d float64) float64 { return d * math.Pi / 180 }
func rad2deg(r float64) float64 { return r * 180 / math.Pi }
func mean_angle(deg []float64) float64 {
sum := 0i
for _, x := range deg {
sum += cmplx.Rect(1, deg2rad(x))
}
return rad2deg(cmplx.Ph... |
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 ... | #Clojure | Clojure | (defn median [ns]
(let [ns (sort ns)
cnt (count ns)
mid (bit-shift-right cnt 1)]
(if (odd? cnt)
(nth ns mid)
(/ (+ (nth ns mid) (nth ns (dec mid))) 2)))) |
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 ... | #COBOL | COBOL | FUNCTION MEDIAN(some-table (ALL)) |
http://rosettacode.org/wiki/Averages/Pythagorean_means | Averages/Pythagorean means | Task[edit]
Compute all three of the Pythagorean means of the set of integers 1 through 10 (inclusive).
Show that
A
(
x
1
,
…
,
x
n
)
≥
G
(
x
1
,
…
,
x
n
)
≥
H
(
x
1
,
…
,
x
n
)
{\displaystyle A(x_{1},\ldots ,x_{n})\geq G(x_{1},\ldots ,x_{n})\geq H(x_{1},\ldots ,x_{n})}
for this set of p... | #Futhark | Futhark |
fun arithmetic_mean(as: [n]f64): f64 =
reduce (+) 0.0 (map (/f64(n)) as)
fun geometric_mean(as: [n]f64): f64 =
reduce (*) 1.0 (map (**(1.0/f64(n))) as)
fun harmonic_mean(as: [n]f64): f64 =
f64(n) / reduce (+) 0.0 (map (1.0/) as)
fun main(as: [n]f64): (f64,f64,f64) =
(arithmetic_mean as,
geometric_mea... |
http://rosettacode.org/wiki/Balanced_ternary | Balanced ternary | Balanced ternary is a way of representing numbers. Unlike the prevailing binary representation, a balanced ternary integer is in base 3, and each digit can have the values 1, 0, or −1.
Examples
Decimal 11 = 32 + 31 − 30, thus it can be written as "++−"
Decimal 6 = 32 − 31 + 0 × 30, thus it can be written as "+−0"
... | #Kotlin | Kotlin | // version 1.1.3
import java.math.BigInteger
val bigZero = BigInteger.ZERO
val bigOne = BigInteger.ONE
val bigThree = BigInteger.valueOf(3L)
data class BTernary(private var value: String) : Comparable<BTernary> {
init {
require(value.all { it in "0+-" })
value = value.trimStart('0')
}
... |
http://rosettacode.org/wiki/Babbage_problem | Babbage problem |
Charles Babbage, looking ahead to the sorts of problems his Analytical Engine would be able to solve, gave this example:
What is the smallest positive integer whose square ends in the digits 269,696?
— Babbage, letter to Lord Bowden, 1837; see Hollingdale and Tootill, Electronic Computers, second edition, 1970, p.... | #PHP | PHP | <?php
for (
$i = 1 ; // Initial positive integer to check
($i * $i) % 1000000 !== 269696 ; // While i*i does not end with the digits 269,696
$i++ // ... go to next integer
);
echo $i, ' * ', $i, ' = ', ($i * $i), PHP_EO... |
http://rosettacode.org/wiki/Approximate_equality | Approximate equality | Sometimes, when testing whether the solution to a task (for example, here on Rosetta Code) is correct, the
difference in floating point calculations between different language implementations becomes significant.
For example, a difference between 32 bit and 64 bit floating point calculations may appear by
about the 8t... | #C.2B.2B | C++ | #include <iomanip>
#include <iostream>
#include <cmath>
bool approxEquals(double a, double b, double e) {
return fabs(a - b) < e;
}
void test(double a, double b) {
constexpr double epsilon = 1e-18;
std::cout << std::setprecision(21) << a;
std::cout << ", ";
std::cout << std::setprecision(21) << ... |
http://rosettacode.org/wiki/Balanced_brackets | Balanced brackets | Task:
Generate a string with N opening brackets [ and with N closing brackets ], in some arbitrary order.
Determine whether the generated string is balanced; that is, whether it consists entirely of pairs of opening/closing brackets (in that order), none of which mis-nest.
Examples
(empty) ... | #C | C | #include<stdio.h>
#include<stdlib.h>
#include<string.h>
int isBal(const char*s,int l){
signed c=0;
while(l--)
if(s[l]==']') ++c;
else if(s[l]=='[') if(--c<0) break;
return !c;
}
void shuffle(char*s,int h){
int x,t,i=h;
while(i--){
t=s[x=rand()%h];
s[x]=s[i];
s[i]=t;
}
}
void genSeq(ch... |
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... | #11l | 11l | V dict = [‘key1’ = 1, ‘key2’ = 2]
V value2 = dict[‘key2’] |
http://rosettacode.org/wiki/Atomic_updates | Atomic updates |
Task
Define a data type consisting of a fixed number of 'buckets', each containing a nonnegative integer value, which supports operations to:
get the current value of any bucket
remove a specified amount from one specified bucket and add it to another, preserving the total of all bucket values, and clamping the t... | #Clojure | Clojure | (defn xfer [m from to amt]
(let [{f-bal from t-bal to} m
f-bal (- f-bal amt)
t-bal (+ t-bal amt)]
(if (or (neg? f-bal) (neg? t-bal))
(throw (IllegalArgumentException. "Call results in negative balance."))
(assoc m from f-bal to t-bal)))) |
http://rosettacode.org/wiki/Atomic_updates | Atomic updates |
Task
Define a data type consisting of a fixed number of 'buckets', each containing a nonnegative integer value, which supports operations to:
get the current value of any bucket
remove a specified amount from one specified bucket and add it to another, preserving the total of all bucket values, and clamping the t... | #Common_Lisp | Common Lisp | (ql:quickload '(:alexandria :stmx :bordeaux-threads))
(defpackage :atomic-updates
(:use :cl))
(in-package :atomic-updates)
(defvar *buckets* nil)
(defvar *running* nil)
(defun distribute (ratio a b)
"Atomically redistribute the values of buckets A and B by RATIO."
(stmx:atomic
(let* ((sum (+ (stmx:$ a)... |
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.
| #BBC_BASIC | BBC BASIC | PROCassert(a% = 42)
END
DEF PROCassert(bool%)
IF NOT bool% THEN ERROR 100, "Assertion failed"
ENDPROC |
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.
| #BQN | BQN | ! 2=3 # Failed
Error: Assertion error
at ! 2=3 # Failed
^
"hello" ! 2=3 # Failed
Error: hello
at "hello" ! 2=3 # Failed |
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.
| #Brat | Brat | squish import :assert :assertions
assert_equal 42 42
assert_equal 13 42 #Raises an exception |
http://rosettacode.org/wiki/Averages/Mode | Averages/Mode | Task[edit]
Write a program to find the mode value of a collection.
The case where the collection is empty may be ignored. Care must be taken to handle the case where the mode is non-unique.
If it is not appropriate or possible to support a general collection, use a vector (array), if possible. If it is not appropriat... | #JavaScript | JavaScript | function mode(ary) {
var counter = {};
var mode = [];
var max = 0;
for (var i in ary) {
if (!(ary[i] in counter))
counter[ary[i]] = 0;
counter[ary[i]]++;
if (counter[ary[i]] == max)
mode.push(ary[i]);
else if (counter[ary[i]] > max) {
... |
http://rosettacode.org/wiki/Associative_array/Iteration | Associative array/Iteration | Show how to iterate over the key-value pairs of an associative array, and print each pair out.
Also show how to iterate just over the keys, or the values, if there is a separate way to do that in your language.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked ... | #Aime | Aime | record r;
text s;
r_put(r, "A", 33); # an integer value
r_put(r, "C", 2.5); # a real value
r_put(r, "B", "associative"); # a string value
if (r_first(r, s)) {
do {
o_form("key ~, value ~ (~)\n", s, r[s], r_type(r, s));
} while (rsk_greater(r, s, s));
} |
http://rosettacode.org/wiki/Associative_array/Iteration | Associative array/Iteration | Show how to iterate over the key-value pairs of an associative array, and print each pair out.
Also show how to iterate just over the keys, or the values, if there is a separate way to do that in your language.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked ... | #ALGOL_68 | ALGOL 68 | # associative array handling using hashing #
# the modes allowed as associative array element values - change to suit #
MODE AAVALUE = STRING;
# the modes allowed as associative array element keys - change to suit #
MODE AAKEY = STRING;
# nil element value ... |
http://rosettacode.org/wiki/Apply_a_digital_filter_(direct_form_II_transposed) | Apply a digital filter (direct form II transposed) | Digital filters are used to apply a mathematical operation to a sampled signal. One of the common formulations is the "direct form II transposed" which can represent both infinite impulse response (IIR) and finite impulse response (FIR) filters, as well as being more numerically stable than other forms. [1]
Task
Filt... | #ALGOL_68 | ALGOL 68 | BEGIN # apply a digital filter #
PROC filter = ( []REAL a, b, signal, REF[]REAL result )VOID:
BEGIN
FOR i FROM LWB result TO UPB result DO result[ i ] := 0 OD;
FOR i FROM LWB signal TO UPB signal DO
REAL tmp := 0;
FOR j FROM LWB b TO UPB b DO
... |
http://rosettacode.org/wiki/Averages/Arithmetic_mean | Averages/Arithmetic mean | Task[edit]
Write a program to find the mean (arithmetic average) of a numeric vector.
In case of a zero-length input, since the mean of an empty set of numbers is ill-defined, the program may choose to behave in any way it deems appropriate, though if the programming language has an established convention for conveyin... | #AutoHotkey | AutoHotkey | i = 10
Loop, % i {
Random, v, -3.141592, 3.141592
list .= v "`n"
sum += v
}
MsgBox, % i ? list "`nmean: " sum/i:0 |
http://rosettacode.org/wiki/Averages/Arithmetic_mean | Averages/Arithmetic mean | Task[edit]
Write a program to find the mean (arithmetic average) of a numeric vector.
In case of a zero-length input, since the mean of an empty set of numbers is ill-defined, the program may choose to behave in any way it deems appropriate, though if the programming language has an established convention for conveyin... | #AWK | AWK | cat mean.awk
#!/usr/local/bin/gawk -f
# User defined function
function mean(v, i,n,sum) {
for (i in v) {
n++
sum += v[i]
}
if (n>0) {
return(sum/n)
} else {
return("zero-length input !")
}
}
BEGIN {
# fill a vector with random numbers
for(i=0; i < 10; i++) {
vett[i] = rand()*1... |
http://rosettacode.org/wiki/Associative_array/Merging | Associative array/Merging | Task
Define two associative arrays, where one represents the following "base" data:
Key
Value
"name"
"Rocket Skates"
"price"
12.75
"color"
"yellow"
And the other represents "update" data:
Key
Value
"price"
15.25
"color"
"red"
"year"
1974
Merge these into a new associativ... | #Elixir | Elixir | base = %{name: "Rocket Skates", price: 12.75, color: "yellow"}
update = %{price: 15.25, color: "red", year: 1974}
result = Map.merge(base, update)
IO.inspect(result) |
http://rosettacode.org/wiki/Associative_array/Merging | Associative array/Merging | Task
Define two associative arrays, where one represents the following "base" data:
Key
Value
"name"
"Rocket Skates"
"price"
12.75
"color"
"yellow"
And the other represents "update" data:
Key
Value
"price"
15.25
"color"
"red"
"year"
1974
Merge these into a new associativ... | #F.23 | F# |
type N = |Price of float|Name of string|Year of int|Colour of string
let n=Map<string,N>[("name",Name("Rocket Skates"));("price",Price(12.75));("colour",Colour("yellow"))]
let g=Map<string,N>[("price",Price(15.25));("colour",Colour("red"));("year",Year(1974))]
let ng=(Map.toList n)@(Map.toList g)|>Map.ofList
printfn ... |
http://rosettacode.org/wiki/Associative_array/Merging | Associative array/Merging | Task
Define two associative arrays, where one represents the following "base" data:
Key
Value
"name"
"Rocket Skates"
"price"
12.75
"color"
"yellow"
And the other represents "update" data:
Key
Value
"price"
15.25
"color"
"red"
"year"
1974
Merge these into a new associativ... | #Factor | Factor | USING: assocs prettyprint ;
{ { "name" "Rocket Skates" } { "price" 12.75 } { "color" "yellow" } }
{ { "price" 15.25 } { "color" "red" } { "year" 1974 } }
assoc-union . |
http://rosettacode.org/wiki/Average_loop_length | Average loop length | Let f be a uniformly-randomly chosen mapping from the numbers 1..N to the numbers 1..N (note: not necessarily a permutation of 1..N; the mapping could produce a number in more than one way or not at all). At some point, the sequence 1, f(1), f(f(1))... will contain a repetition, a number that occurring for the second t... | #FutureBasic | FutureBasic |
_nmax = 20
_times = 1000000
local fn Average( n as long, times as long ) as double
long i, x
double b, c = 0
for i = 0 to times
x = 1 : b = 0
while ( b and x ) == 0
c++
b = b || x
x = 1 << ( rnd(n) - 1 )
wend
next
end fn = c / times
local fn Analyltic( n as long ) as doub... |
http://rosettacode.org/wiki/Average_loop_length | Average loop length | Let f be a uniformly-randomly chosen mapping from the numbers 1..N to the numbers 1..N (note: not necessarily a permutation of 1..N; the mapping could produce a number in more than one way or not at all). At some point, the sequence 1, f(1), f(f(1))... will contain a repetition, a number that occurring for the second t... | #Go | Go | package main
import (
"fmt"
"math"
"math/rand"
)
const nmax = 20
func main() {
fmt.Println(" N average analytical (error)")
fmt.Println("=== ========= ============ =========")
for n := 1; n <= nmax; n++ {
a := avg(n)
b := ana(n)
fmt.Printf("%3d %9.4f %... |
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... | #Python | Python | from collections import deque
def simplemovingaverage(period):
assert period == int(period) and period > 0, "Period must be an integer >0"
summ = n = 0.0
values = deque([0.0] * period) # old value queue
def sma(x):
nonlocal summ, n
values.append(x)
summ += x - values.... |
http://rosettacode.org/wiki/Attractive_numbers | Attractive numbers | A number is an attractive number if the number of its prime factors (whether distinct or not) is also prime.
Example
The number 20, whose prime decomposition is 2 × 2 × 5, is an attractive number because the number of its prime factors (3) is also prime.
Task
Show sequence items up to 120.... | #Cowgol | Cowgol | include "cowgol.coh";
const MAXIMUM := 120;
typedef N is int(0, MAXIMUM + 1);
var prime: uint8[MAXIMUM + 1];
sub Sieve() is
MemSet(&prime[0], 1, @bytesof prime);
prime[0] := 0;
prime[1] := 0;
var cand: N := 2;
while cand <= MAXIMUM >> 1 loop
if prime[cand] != 0 then
var com... |
http://rosettacode.org/wiki/Attractive_numbers | Attractive numbers | A number is an attractive number if the number of its prime factors (whether distinct or not) is also prime.
Example
The number 20, whose prime decomposition is 2 × 2 × 5, is an attractive number because the number of its prime factors (3) is also prime.
Task
Show sequence items up to 120.... | #D | D | import std.stdio;
enum MAX = 120;
bool isPrime(int n) {
if (n < 2) return false;
if (n % 2 == 0) return n == 2;
if (n % 3 == 0) return n == 3;
int d = 5;
while (d * d <= n) {
if (n % d == 0) return false;
d += 2;
if (n % d == 0) return false;
d += 4;
}
ret... |
http://rosettacode.org/wiki/Averages/Mean_time_of_day | Averages/Mean time of day | Task[edit]
A particular activity of bats occurs at these times of the day:
23:00:17, 23:40:20, 00:12:45, 00:17:19
Using the idea that there are twenty-four hours in a day,
which is analogous to there being 360 degrees in a circle,
map times of day to and from angles;
and using the ideas of Averages/Mean angle
compute ... | #Java | Java | public class MeanTimeOfDay {
static double meanAngle(double[] angles) {
int len = angles.length;
double sinSum = 0.0;
for (int i = 0; i < len; i++) {
sinSum += Math.sin(angles[i] * Math.PI / 180.0);
}
double cosSum = 0.0;
for (int i = 0; i < len; i++) ... |
http://rosettacode.org/wiki/AVL_tree | AVL tree |
This page uses content from Wikipedia. The original article was at AVL tree. 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 computer science, an AVL tree is a self-balancing binary search tree.... | #JavaScript | JavaScript | function tree(less, val, more) {
return {
depth: 1+Math.max(less.depth, more.depth),
less: less,
val: val,
more: more,
};
}
function node(val) {
return tree({depth: 0}, val, {depth: 0});
}
function insert(x,y) {
if (0 == y.depth) return x;
if (0 == x.depth) return y;
if (1 == x.depth && ... |
http://rosettacode.org/wiki/Averages/Mean_angle | Averages/Mean angle | When calculating the average or mean of an angle one has to take into account how angles wrap around so that any angle in degrees plus any integer multiple of 360 degrees is a measure of the same angle.
If one wanted an average direction of the wind over two readings where the first reading was of 350 degrees and the ... | #Groovy | Groovy | import static java.lang.Math.*
def meanAngle = {
atan2( it.sum { sin(it * PI / 180) } / it.size(), it.sum { cos(it * PI / 180) } / it.size()) * 180 / PI
} |
http://rosettacode.org/wiki/Averages/Mean_angle | Averages/Mean angle | When calculating the average or mean of an angle one has to take into account how angles wrap around so that any angle in degrees plus any integer multiple of 360 degrees is a measure of the same angle.
If one wanted an average direction of the wind over two readings where the first reading was of 350 degrees and the ... | #Haskell | Haskell | import Data.Complex (cis, phase)
meanAngle
:: RealFloat c
=> [c] -> c
meanAngle = (/ pi) . (* 180) . phase . sum . map (cis . (/ 180) . (* pi))
main :: IO ()
main =
mapM_
(\angles ->
putStrLn $
"The mean angle of " ++
show angles ++ " is: " ++ show (meanAngle angles) ++ " degrees")... |
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 ... | #Common_Lisp | Common Lisp | ((defun select-nth (n list predicate)
"Select nth element in list, ordered by predicate, modifying list."
(do ((pivot (pop list))
(ln 0) (left '())
(rn 0) (right '()))
((endp list)
(cond
((< n ln) (select-nth n left predicate))
((eql n ln) pivot)
((< n (+ ln rn 1))... |
http://rosettacode.org/wiki/Averages/Pythagorean_means | Averages/Pythagorean means | Task[edit]
Compute all three of the Pythagorean means of the set of integers 1 through 10 (inclusive).
Show that
A
(
x
1
,
…
,
x
n
)
≥
G
(
x
1
,
…
,
x
n
)
≥
H
(
x
1
,
…
,
x
n
)
{\displaystyle A(x_{1},\ldots ,x_{n})\geq G(x_{1},\ldots ,x_{n})\geq H(x_{1},\ldots ,x_{n})}
for this set of p... | #GAP | GAP | # The first two work with rationals or with floats
# (but bear in mind that support of floating point is very poor in GAP)
mean := v -> Sum(v) / Length(v);
harmean := v -> Length(v) / Sum(v, Inverse);
geomean := v -> EXP_FLOAT(Sum(v, LOG_FLOAT) / Length(v));
mean([1 .. 10]);
# 11/2
harmean([1 .. 10]);
# 25200/7381
... |
http://rosettacode.org/wiki/Balanced_ternary | Balanced ternary | Balanced ternary is a way of representing numbers. Unlike the prevailing binary representation, a balanced ternary integer is in base 3, and each digit can have the values 1, 0, or −1.
Examples
Decimal 11 = 32 + 31 − 30, thus it can be written as "++−"
Decimal 6 = 32 − 31 + 0 × 30, thus it can be written as "+−0"
... | #Liberty_BASIC | Liberty BASIC |
global tt$
tt$="-0+" '-1 0 1; +2 -> 1 2 3, instr
'Test case:
'With balanced ternaries a from string "+-0++0+", b from native integer -436, c "+-++-":
'* write out a, b and c in decimal notation;
'* calculate a * (b - c), write out the result in both ternary and decimal notations.
a$="+-0++0+"
a=deci(a$)
print "... |
http://rosettacode.org/wiki/Babbage_problem | Babbage problem |
Charles Babbage, looking ahead to the sorts of problems his Analytical Engine would be able to solve, gave this example:
What is the smallest positive integer whose square ends in the digits 269,696?
— Babbage, letter to Lord Bowden, 1837; see Hollingdale and Tootill, Electronic Computers, second edition, 1970, p.... | #Picat | Picat | main =>
N = 1,
while (N**2 mod 1000000 != 269696)
N := N + 1
end,
println(N). |
http://rosettacode.org/wiki/Babbage_problem | Babbage problem |
Charles Babbage, looking ahead to the sorts of problems his Analytical Engine would be able to solve, gave this example:
What is the smallest positive integer whose square ends in the digits 269,696?
— Babbage, letter to Lord Bowden, 1837; see Hollingdale and Tootill, Electronic Computers, second edition, 1970, p.... | #PicoLisp | PicoLisp | : (for N 99736 # Iterate N from 1 to 99736
(T (= 269696 (% (* N N) 1000000)) N) ) # Stop if remainder is 269696
-> 25264 |
http://rosettacode.org/wiki/Approximate_equality | Approximate equality | Sometimes, when testing whether the solution to a task (for example, here on Rosetta Code) is correct, the
difference in floating point calculations between different language implementations becomes significant.
For example, a difference between 32 bit and 64 bit floating point calculations may appear by
about the 8t... | #Common_Lisp | Common Lisp |
(defun approx-equal (float1 float2 &optional (threshold 0.000001))
"Determine whether float1 and float2 are equal; THRESHOLD is the
maximum allowable difference between normalized significands of floats
with the same exponent. The significands are scaled appropriately
before comparison for floats with different exp... |
http://rosettacode.org/wiki/Approximate_equality | Approximate equality | Sometimes, when testing whether the solution to a task (for example, here on Rosetta Code) is correct, the
difference in floating point calculations between different language implementations becomes significant.
For example, a difference between 32 bit and 64 bit floating point calculations may appear by
about the 8t... | #D | D | import std.math;
import std.stdio;
auto approxEquals = (double a, double b, double epsilon) => abs(a - b) < epsilon;
void main() {
void test(double a, double b) {
double epsilon = 1e-18;
writefln("%.18f, %.18f => %s", a, b, a.approxEquals(b, epsilon));
}
test(100000000000000.01, 100000... |
http://rosettacode.org/wiki/Balanced_brackets | Balanced brackets | Task:
Generate a string with N opening brackets [ and with N closing brackets ], in some arbitrary order.
Determine whether the generated string is balanced; that is, whether it consists entirely of pairs of opening/closing brackets (in that order), none of which mis-nest.
Examples
(empty) ... | #C.23 | C# | using System;
using System.Linq;
class Program
{
static bool IsBalanced(string text, char open = '[', char close = ']')
{
var level = 0;
foreach (var character in text)
{
if (character == close)
{
if (level == 0)
{
... |
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... | #8th | 8th |
{ "one" : 1, "two" : "bad" }
|
http://rosettacode.org/wiki/Atomic_updates | Atomic updates |
Task
Define a data type consisting of a fixed number of 'buckets', each containing a nonnegative integer value, which supports operations to:
get the current value of any bucket
remove a specified amount from one specified bucket and add it to another, preserving the total of all bucket values, and clamping the t... | #D | D | import std.stdio: writeln;
import std.conv: text;
import std.random: uniform, Xorshift;
import std.algorithm: min, max;
import std.parallelism: task;
import core.thread: Thread;
import core.sync.mutex: Mutex;
import core.time: seconds;
__gshared uint transfersCount;
final class Buckets(size_t nBuckets) if (nBuckets... |
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.
| #C | C | #include <assert.h>
int main(){
int a;
/* ...input or change a here */
assert(a == 42); /* aborts program when a is not 42, unless the NDEBUG macro was defined */
return 0;
} |
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.
| #C.23_and_Visual_Basic_.NET | C# and Visual Basic .NET | using System.Diagnostics; // Debug and Trace are in this namespace.
static class Program
{
static void Main()
{
int a = 0;
Console.WriteLine("Before");
// Always hit.
Trace.Assert(a == 42, "Trace assertion failed");
Console.WriteLine("After Trace.Assert");
... |
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.
| #11l | 11l | V array = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
V arrsq = array.map(i -> i * i)
print(arrsq) |
http://rosettacode.org/wiki/Averages/Mode | Averages/Mode | Task[edit]
Write a program to find the mode value of a collection.
The case where the collection is empty may be ignored. Care must be taken to handle the case where the mode is non-unique.
If it is not appropriate or possible to support a general collection, use a vector (array), if possible. If it is not appropriat... | #jq | jq | # modes/0 produces an array of [value, count]
# in increasing order of count:
def modes:
sort | reduce .[] as $i ([];
# state variable is an array of [value, count]
if length == 0 then [ [$i, 1] ]
elif .[-1][0] == $i then setpath([-1,1]; .[-1][1] + 1)
else . + [[$i,1]]
end )
| sort_by( .[1] );... |
http://rosettacode.org/wiki/Averages/Mode | Averages/Mode | Task[edit]
Write a program to find the mode value of a collection.
The case where the collection is empty may be ignored. Care must be taken to handle the case where the mode is non-unique.
If it is not appropriate or possible to support a general collection, use a vector (array), if possible. If it is not appropriat... | #Julia | Julia | function modes(values)
dict = Dict() # Values => Number of repetitions
modesArray = typeof(values[1])[] # Array of the modes so far
max = 0 # Max of repetitions so far
for v in values
# Add one to the dict[v] entry (create one if none)
if v in keys(dict)
dict[v] += 1
... |
http://rosettacode.org/wiki/Associative_array/Iteration | Associative array/Iteration | Show how to iterate over the key-value pairs of an associative array, and print each pair out.
Also show how to iterate just over the keys, or the values, if there is a separate way to do that in your language.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked ... | #App_Inventor | App Inventor | ; create a dictionary
d: #[
name: "john"
surname: "doe"
age: 34
]
; Iterate over key/value pairs
loop d [key,value][
print ["key =" key ", value =" value]
]
print "----"
; Iterate over keys
loop keys d [k][
print ["key =" k]
]
print "----"
; Iterate over values
loop values d [v][
print ["value =" v... |
http://rosettacode.org/wiki/Associative_array/Iteration | Associative array/Iteration | Show how to iterate over the key-value pairs of an associative array, and print each pair out.
Also show how to iterate just over the keys, or the values, if there is a separate way to do that in your language.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked ... | #Arturo | Arturo | ; create a dictionary
d: #[
name: "john"
surname: "doe"
age: 34
]
; Iterate over key/value pairs
loop d [key,value][
print ["key =" key ", value =" value]
]
print "----"
; Iterate over keys
loop keys d [k][
print ["key =" k]
]
print "----"
; Iterate over values
loop values d [v][
print ["value =" v... |
http://rosettacode.org/wiki/Apply_a_digital_filter_(direct_form_II_transposed) | Apply a digital filter (direct form II transposed) | Digital filters are used to apply a mathematical operation to a sampled signal. One of the common formulations is the "direct form II transposed" which can represent both infinite impulse response (IIR) and finite impulse response (FIR) filters, as well as being more numerically stable than other forms. [1]
Task
Filt... | #AppleScript | AppleScript | on min(a, b)
if (b < a) then return b
return a
end min
on DF2TFilter(a, b, sig)
set aCount to (count a)
set bCount to (count b)
set sigCount to (count sig)
set rst to {}
repeat with i from 1 to sigCount
set tmp to 0
set iPlus1 to i + 1
repeat with j from 1 to min(... |
http://rosettacode.org/wiki/Averages/Arithmetic_mean | Averages/Arithmetic mean | Task[edit]
Write a program to find the mean (arithmetic average) of a numeric vector.
In case of a zero-length input, since the mean of an empty set of numbers is ill-defined, the program may choose to behave in any way it deems appropriate, though if the programming language has an established convention for conveyin... | #Babel | Babel | (3 24 18 427 483 49 14 4294 2 41) dup len <- sum ! -> / itod << |
http://rosettacode.org/wiki/Averages/Arithmetic_mean | Averages/Arithmetic mean | Task[edit]
Write a program to find the mean (arithmetic average) of a numeric vector.
In case of a zero-length input, since the mean of an empty set of numbers is ill-defined, the program may choose to behave in any way it deems appropriate, though if the programming language has an established convention for conveyin... | #BASIC | BASIC | mean = 0
sum = 0;
FOR i = LBOUND(nums) TO UBOUND(nums)
sum = sum + nums(i);
NEXT i
size = UBOUND(nums) - LBOUND(nums) + 1
PRINT "The mean is: ";
IF size <> 0 THEN
PRINT (sum / size)
ELSE
PRINT 0
END IF |
http://rosettacode.org/wiki/Associative_array/Merging | Associative array/Merging | Task
Define two associative arrays, where one represents the following "base" data:
Key
Value
"name"
"Rocket Skates"
"price"
12.75
"color"
"yellow"
And the other represents "update" data:
Key
Value
"price"
15.25
"color"
"red"
"year"
1974
Merge these into a new associativ... | #Go | Go | package main
import "fmt"
type assoc map[string]interface{}
func merge(base, update assoc) assoc {
result := make(assoc)
for k, v := range base {
result[k] = v
}
for k, v := range update {
result[k] = v
}
return result
}
func main() {
base := assoc{"name": "Rocket Ska... |
http://rosettacode.org/wiki/Associative_array/Merging | Associative array/Merging | Task
Define two associative arrays, where one represents the following "base" data:
Key
Value
"name"
"Rocket Skates"
"price"
12.75
"color"
"yellow"
And the other represents "update" data:
Key
Value
"price"
15.25
"color"
"red"
"year"
1974
Merge these into a new associativ... | #Haskell | Haskell | data Item = Item
{ name :: Maybe String
, price :: Maybe Float
, color :: Maybe String
, year :: Maybe Int
} deriving (Show)
itemFromMerge :: Item -> Item -> Item
itemFromMerge (Item n p c y) (Item n1 p1 c1 y1) =
Item (maybe n pure n1) (maybe p pure p1) (maybe c pure c1) (maybe y pure y1)
main :: IO ()
... |
http://rosettacode.org/wiki/Average_loop_length | Average loop length | Let f be a uniformly-randomly chosen mapping from the numbers 1..N to the numbers 1..N (note: not necessarily a permutation of 1..N; the mapping could produce a number in more than one way or not at all). At some point, the sequence 1, f(1), f(f(1))... will contain a repetition, a number that occurring for the second t... | #Haskell | Haskell | import System.Random
import qualified Data.Set as S
import Text.Printf
findRep :: (Random a, Integral a, RandomGen b) => a -> b -> (a, b)
findRep n gen = findRep' (S.singleton 1) 1 gen
where
findRep' seen len gen'
| S.member fx seen = (len, gen'')
| otherwise = findRep' (S.insert ... |
http://rosettacode.org/wiki/Average_loop_length | Average loop length | Let f be a uniformly-randomly chosen mapping from the numbers 1..N to the numbers 1..N (note: not necessarily a permutation of 1..N; the mapping could produce a number in more than one way or not at all). At some point, the sequence 1, f(1), f(f(1))... will contain a repetition, a number that occurring for the second t... | #J | J | (~.@, {&0 0@{:)^:_] 0
0
(~.@, {&0 0@{:)^:_] 1
1 0 |
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... | #Quackery | Quackery | [ $ "bigrat.qky" loadfile ] now!
[ over size -
space swap of
join ] is pad ( $ n --> $ )
[ ' [ stack [ ] ]
copy nested
' [ tuck take swap join
dup size ] join
swap join
' [ > if
[ 1 split nip ]
tuck swap put
0 over witheach +
... |
http://rosettacode.org/wiki/Attractive_numbers | Attractive numbers | A number is an attractive number if the number of its prime factors (whether distinct or not) is also prime.
Example
The number 20, whose prime decomposition is 2 × 2 × 5, is an attractive number because the number of its prime factors (3) is also prime.
Task
Show sequence items up to 120.... | #Delphi | Delphi | /* Sieve of Eratosthenes */
proc nonrec sieve([*] bool prime) void:
word p, c, max;
max := (dim(prime,1)-1)>>1;
prime[0] := false;
prime[1] := false;
for p from 2 upto max do prime[p] := true od;
for p from 2 upto max>>1 do
if prime[p] then
for c from p*2 by p upto max do
... |
http://rosettacode.org/wiki/Attractive_numbers | Attractive numbers | A number is an attractive number if the number of its prime factors (whether distinct or not) is also prime.
Example
The number 20, whose prime decomposition is 2 × 2 × 5, is an attractive number because the number of its prime factors (3) is also prime.
Task
Show sequence items up to 120.... | #Draco | Draco | /* Sieve of Eratosthenes */
proc nonrec sieve([*] bool prime) void:
word p, c, max;
max := (dim(prime,1)-1)>>1;
prime[0] := false;
prime[1] := false;
for p from 2 upto max do prime[p] := true od;
for p from 2 upto max>>1 do
if prime[p] then
for c from p*2 by p upto max do
... |
http://rosettacode.org/wiki/Averages/Mean_time_of_day | Averages/Mean time of day | Task[edit]
A particular activity of bats occurs at these times of the day:
23:00:17, 23:40:20, 00:12:45, 00:17:19
Using the idea that there are twenty-four hours in a day,
which is analogous to there being 360 degrees in a circle,
map times of day to and from angles;
and using the ideas of Averages/Mean angle
compute ... | #JavaScript | JavaScript | var args = process.argv.slice(2);
function time_to_seconds( hms ) {
var parts = hms.split(':');
var h = parseInt(parts[0]);
var m = parseInt(parts[1]);
var s = parseInt(parts[2]);
if ( h < 12 ) {
h += 24;
}
var seconds = parseInt(parts[0]) * 60 * 60 + parseInt(parts[1]) * 60 + par... |
http://rosettacode.org/wiki/AVL_tree | AVL tree |
This page uses content from Wikipedia. The original article was at AVL tree. 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 computer science, an AVL tree is a self-balancing binary search tree.... | #Julia | Julia | module AVLTrees
import Base.print
export AVLNode, AVLTree, insert, deletekey, deletevalue, findnodebykey, findnodebyvalue, allnodes
@enum Direction LEFT RIGHT
avlhash(x) = Int32(hash(x) & 0xfffffff)
const MIDHASH = Int32(div(0xfffffff, 2))
mutable struct AVLNode{T}
value::T
key::Int32
balance::Int32
... |
http://rosettacode.org/wiki/Averages/Mean_angle | Averages/Mean angle | When calculating the average or mean of an angle one has to take into account how angles wrap around so that any angle in degrees plus any integer multiple of 360 degrees is a measure of the same angle.
If one wanted an average direction of the wind over two readings where the first reading was of 350 degrees and the ... | #Icon_and_Unicon | Icon and Unicon | procedure main(A)
write("Mean angle is ",meanAngle(A))
end
procedure meanAngle(A)
every (sumSines := 0.0) +:= sin(dtor(!A))
every (sumCosines := 0.0) +:= cos(dtor(!A))
return rtod(atan(sumSines/*A,sumCosines/*A))
end |
http://rosettacode.org/wiki/Averages/Mean_angle | Averages/Mean angle | When calculating the average or mean of an angle one has to take into account how angles wrap around so that any angle in degrees plus any integer multiple of 360 degrees is a measure of the same angle.
If one wanted an average direction of the wind over two readings where the first reading was of 350 degrees and the ... | #IDL | IDL | function mean_angle, phi
z = total(exp(complex(0,phi*!dtor)))
return, atan(imaginary(z),real_part(z))*!radeg
end |
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 ... | #Crystal | Crystal | def median(ary)
srtd = ary.sort
alen = srtd.size
0.5*(srtd[(alen-1)//2] + srtd[alen//2])
end
a = [4.1, 5.6, 7.2, 1.7, 9.3, 4.4, 3.2]
puts median a
a = [4.1, 5.6, 7.2, 1.7, 9.3, 4.4, 3.2, 5.0]
puts median a
a = [5.0]
puts median a
|
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