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http://rosettacode.org/wiki/Ethiopian_multiplication
Ethiopian multiplication
Ethiopian multiplication is a method of multiplying integers using only addition, doubling, and halving. Method: Take two numbers to be multiplied and write them down at the top of two columns. In the left-hand column repeatedly halve the last number, discarding any remainders, and write the result below the last ...
#Metafont
Metafont
vardef halve(expr x) = floor(x/2) enddef; vardef double(expr x) = x*2 enddef; vardef iseven(expr x) = if (x mod 2) = 0: true else: false fi enddef;   primarydef a ethiopicmult b = begingroup save r_, plier_, plicand_; plier_ := a; plicand_ := b; r_ := 0; forever: exitif plier_ < 1; if not iseven...
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...
#Wren
Wren
var start = System.clock var n = 250 var m = 30   var p5 = List.filled(n+m+1, 0) var s = 0 while (s < n) { var sq = s * s p5[s] = sq * sq * s s = s + 1 } var max = p5[n-1] while (s < p5.count) { p5[s] = max + 1 s = s + 1 } for (a in 1...n-3) { for (b in a + 1...n-2) { for (c in b + 1...n...
http://rosettacode.org/wiki/Factorial
Factorial
Definitions   The factorial of   0   (zero)   is defined as being   1   (unity).   The   Factorial Function   of a positive integer,   n,   is defined as the product of the sequence: n,   n-1,   n-2,   ...   1 Task Write a function to return the factorial of a number. Solutions can be iterat...
#Retro
Retro
: <factorial> dup 1 = if; dup 1- <factorial> * ; : factorial dup 0 = [ 1+ ] [ <factorial> ] if ;
http://rosettacode.org/wiki/Even_or_odd
Even or odd
Task Test whether an integer is even or odd. There is more than one way to solve this task: Use the even and odd predicates, if the language provides them. Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd. Divide i by 2. The remainder equals...
#Never
Never
  func isOdd(n : int) -> int { n % 2 == 1 }   func isEven(n : int) -> int { n % 2 == 0 }  
http://rosettacode.org/wiki/Even_or_odd
Even or odd
Task Test whether an integer is even or odd. There is more than one way to solve this task: Use the even and odd predicates, if the language provides them. Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd. Divide i by 2. The remainder equals...
#NewLISP
NewLISP
(odd? 1) (even? 2)
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...
#Nyquist
Nyquist
  (setf emptystring "") ;binds variable'emptystring' to the empty string ""   (let ((emptystring "")) ;; Binds local variable 'emptystring' to the empty string "" (when (string-equal emptystring "") ;;case insensitive string comparison (print "Is an empty string")) ;;bad argument error if not a string (when (...
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...
#oberon-2
oberon-2
  MODULE EmptyString; IMPORT Out; VAR str: ARRAY 64 OF CHAR; BEGIN str := ""; Out.String("for str := ");Out.Char('"');Out.Char('"');Out.Char(';');Out.Ln; Out.String("checking str = ");Out.Char('"');Out.Char('"');Out.String(" Is Empty? ");Out.Bool(str = "");Out.Ln; Out.String("checking str[0] = 0X. Is Empty? "...
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#Little_Man_Computer
Little Man Computer
 
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#Logo
Logo
 
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#LSE
LSE
 
http://rosettacode.org/wiki/Entropy
Entropy
Task Calculate the Shannon entropy   H   of a given input string. Given the discrete random variable X {\displaystyle X} that is a string of N {\displaystyle N} "symbols" (total characters) consisting of n {\displaystyle n} different characters (n=2 for binary), the Shannon entropy of X in bit...
#Sidef
Sidef
func entropy(s) { var counts = Hash.new; s.each { |c| counts{c} := 0 ++ }; var len = s.len; [0, counts.values.map {|count| var freq = count/len; freq * freq.log2 }... ]«-»; }   say entropy("1223334444");
http://rosettacode.org/wiki/Entropy
Entropy
Task Calculate the Shannon entropy   H   of a given input string. Given the discrete random variable X {\displaystyle X} that is a string of N {\displaystyle N} "symbols" (total characters) consisting of n {\displaystyle n} different characters (n=2 for binary), the Shannon entropy of X in bit...
#Standard_ML
Standard ML
val Entropy = fn input => let val N = Real.fromInt (String.size input) ; val term = fn a => Math.ln (a/N) * a / ( Math.ln 2.0 * N ) ; val v0 = Vector.tabulate (255,fn i=>0)  ; val freq = Vector.map Real.fromInt (* List.foldr: count occurrences *...
http://rosettacode.org/wiki/Ethiopian_multiplication
Ethiopian multiplication
Ethiopian multiplication is a method of multiplying integers using only addition, doubling, and halving. Method: Take two numbers to be multiplied and write them down at the top of two columns. In the left-hand column repeatedly halve the last number, discarding any remainders, and write the result below the last ...
#.D0.9C.D0.9A-61.2F52
МК-61/52
П1 П2 <-> П0 ИП0 1 - x#0 29 ИП1 2 * П1 ИП0 2 / [x] П0 2 / {x} x#0 04 ИП2 ИП1 + П2 БП 04 ИП2 С/П
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...
#XPL0
XPL0
func real Pow5(N); int N; real X, P; [X:= float(N); P:= X*X; P:= P*P; return P*X; ];   int X0, X1, X2, X3, Y; real SP; [for X0:= 1 to 250 do for X1:= 1 to X0-1 do for X2:= 1 to X1-1 do for X3:= 1 to X2-1 do [SP:= Pow5(X0) + Pow5(X1) + Pow5(X2) + Pow5(X3); for Y:= X0+1 to 250 do i...
http://rosettacode.org/wiki/Factorial
Factorial
Definitions   The factorial of   0   (zero)   is defined as being   1   (unity).   The   Factorial Function   of a positive integer,   n,   is defined as the product of the sequence: n,   n-1,   n-2,   ...   1 Task Write a function to return the factorial of a number. Solutions can be iterat...
#REXX
REXX
/*REXX pgm computes & shows the factorial of a non─negative integer, and also its length*/ numeric digits 100000 /*100k digits: handles N up to 25k.*/ parse arg n /*obtain optional argument from the CL.*/ if n='' then call er 'no arg...
http://rosettacode.org/wiki/Even_or_odd
Even or odd
Task Test whether an integer is even or odd. There is more than one way to solve this task: Use the even and odd predicates, if the language provides them. Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd. Divide i by 2. The remainder equals...
#Nim
Nim
# Least signficant bit: proc isOdd(i: int): bool = (i and 1) != 0 proc isEven(i: int): bool = (i and 1) == 0   # Modulo: proc isOdd2(i: int): bool = (i mod 2) != 0 proc isEven2(i: int): bool = (i mod 2) == 0   # Bit Shifting: proc isOdd3(n: int): bool = n != ((n shr 1) shl 1) proc isEven3(n: int): bool = n == ((n shr 1...
http://rosettacode.org/wiki/Even_or_odd
Even or odd
Task Test whether an integer is even or odd. There is more than one way to solve this task: Use the even and odd predicates, if the language provides them. Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd. Divide i by 2. The remainder equals...
#Oberon-2
Oberon-2
  MODULE EvenOrOdd; IMPORT S := SYSTEM, Out; VAR x: INTEGER; s: SET;   BEGIN x := 10;Out.Int(x,0); IF ODD(x) THEN Out.String(" odd") ELSE Out.String(" even") END; Out.Ln;   x := 11;s := S.VAL(SET,LONG(x));Out.Int(x,0); IF 0 IN s THEN Out.String(" odd") ELSE Out.String(" even") END; Out.Ln;   x...
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...
#Objeck
Objeck
  s := ""; if(s->IsEmpty()) { "s is empty"->PrintLine(); } else{ "s is not empty"->PrintLine(); };  
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...
#OCaml
OCaml
let is_string_empty s = (s = "")   let () = let s1 = "" and s2 = "not empty" in Printf.printf "s1 empty? %B\n" (is_string_empty s1); Printf.printf "s2 empty? %B\n" (is_string_empty s2); ;;
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#LSE64
LSE64
bye
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#Lua
Lua
 
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#M2000_Interpreter
M2000 Interpreter
  MODULE GLOBAL A { }  
http://rosettacode.org/wiki/Entropy
Entropy
Task Calculate the Shannon entropy   H   of a given input string. Given the discrete random variable X {\displaystyle X} that is a string of N {\displaystyle N} "symbols" (total characters) consisting of n {\displaystyle n} different characters (n=2 for binary), the Shannon entropy of X in bit...
#Swift
Swift
import Foundation   func entropy(of x: String) -> Double { return x .reduce(into: [String: Int](), {cur, char in cur[String(char), default: 0] += 1 }) .values .map({i in Double(i) / Double(x.count) } as (Int) -> Double) .map({p in -p * log2(p) } as (Double) -> Double) .reduce(0.0, +) }  ...
http://rosettacode.org/wiki/Entropy
Entropy
Task Calculate the Shannon entropy   H   of a given input string. Given the discrete random variable X {\displaystyle X} that is a string of N {\displaystyle N} "symbols" (total characters) consisting of n {\displaystyle n} different characters (n=2 for binary), the Shannon entropy of X in bit...
#Tcl
Tcl
proc entropy {str} { set log2 [expr log(2)] foreach char [split $str ""] {dict incr counts $char} set entropy 0.0 foreach count [dict values $counts] { set freq [expr {$count / double([string length $str])}] set entropy [expr {$entropy - $freq * log($freq)/$log2}] } return $entropy }
http://rosettacode.org/wiki/Ethiopian_multiplication
Ethiopian multiplication
Ethiopian multiplication is a method of multiplying integers using only addition, doubling, and halving. Method: Take two numbers to be multiplied and write them down at the top of two columns. In the left-hand column repeatedly halve the last number, discarding any remainders, and write the result below the last ...
#MMIX
MMIX
A IS 17 B IS 34   pliar IS $255 % designating main registers pliand GREG acc GREG str IS pliar % reuse reg $255 for printing   LOC Data_Segment GREG @ BUF OCTA #3030303030303030 % reserve a buffer that is big enough to hold OCTA #3030303030303030 % a max (signed) 64 bit integer: OCTA #3030300a00000000 % 2^63 ...
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...
#Zig
Zig
  const std = @import("std"); const stdout = std.io.getStdOut().outStream();   pub fn main() !void { var pow5: [250]i64 = undefined; for (pow5) |*e, i| { const n = @intCast(i64, i); e.* = n * n * n * n * n; } var x0: u16 = 4; while (x0 < pow5.len) : (x0 += 1) { var x1: u16 = ...
http://rosettacode.org/wiki/Factorial
Factorial
Definitions   The factorial of   0   (zero)   is defined as being   1   (unity).   The   Factorial Function   of a positive integer,   n,   is defined as the product of the sequence: n,   n-1,   n-2,   ...   1 Task Write a function to return the factorial of a number. Solutions can be iterat...
#Ring
Ring
  give n x = fact(n) see n + " factorial is : " + x   func fact nr if nr = 1 return 1 else return nr * fact(nr-1) ok  
http://rosettacode.org/wiki/Even_or_odd
Even or odd
Task Test whether an integer is even or odd. There is more than one way to solve this task: Use the even and odd predicates, if the language provides them. Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd. Divide i by 2. The remainder equals...
#Objeck
Objeck
a := Console->ReadString()->ToInt(); if(a % 2 = 0) { "even"->PrintLine(); } else { "odd"->PrintLine(); };
http://rosettacode.org/wiki/Even_or_odd
Even or odd
Task Test whether an integer is even or odd. There is more than one way to solve this task: Use the even and odd predicates, if the language provides them. Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd. Divide i by 2. The remainder equals...
#OCaml
OCaml
let is_even d = (d mod 2) = 0   let is_odd d = (d mod 2) <> 0
http://rosettacode.org/wiki/Empty_string
Empty string
Languages may have features for dealing specifically with empty strings (those containing no characters). Task   Demonstrate how to assign an empty string to a variable.   Demonstrate how to check that a string is empty.   Demonstrate how to check that a string is not empty. Other tasks related to string oper...
#Oforth
Oforth
"" isEmpty "" isEmpty not
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...
#Ol
Ol
  ; define the empty string (define empty-string "")   ; three simplest tests for 'the-string emptiness (if (or (string-eq? the-string "") (string=? the-string "") (eq? (string-length the-string) 0)) (print "the-string is empty")   ; four simplest tests for 'the-string not emptiness (if (or ...
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#M4
M4
 
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#Maple
Maple
 
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#Mathematica_.2F_Wolfram_Language
Mathematica / Wolfram Language
 
http://rosettacode.org/wiki/Entropy
Entropy
Task Calculate the Shannon entropy   H   of a given input string. Given the discrete random variable X {\displaystyle X} that is a string of N {\displaystyle N} "symbols" (total characters) consisting of n {\displaystyle n} different characters (n=2 for binary), the Shannon entropy of X in bit...
#Vlang
Vlang
import math import arrays   fn hist(source string) map[string]int { mut hist := map[string]int{} for e in source.split('') { if e !in hist { hist[e] = 0 } hist[e]+=1 } return hist }   fn entropy(hist map[string]int, l int) f64 { mut elist := []f64{} for _,v in...
http://rosettacode.org/wiki/Entropy
Entropy
Task Calculate the Shannon entropy   H   of a given input string. Given the discrete random variable X {\displaystyle X} that is a string of N {\displaystyle N} "symbols" (total characters) consisting of n {\displaystyle n} different characters (n=2 for binary), the Shannon entropy of X in bit...
#Wren
Wren
var s = "1223334444" var m = {} for (c in s) { var d = m[c] m[c] = (d) ? d + 1 : 1 } var hm = 0 for (k in m.keys) { var c = m[k] hm = hm + c * c.log2 } var l = s.count System.print(l.log2 - hm/l)
http://rosettacode.org/wiki/Ethiopian_multiplication
Ethiopian multiplication
Ethiopian multiplication is a method of multiplying integers using only addition, doubling, and halving. Method: Take two numbers to be multiplied and write them down at the top of two columns. In the left-hand column repeatedly halve the last number, discarding any remainders, and write the result below the last ...
#Modula-2
Modula-2
  MODULE EthiopianMultiplication;   FROM SWholeIO IMPORT WriteCard; FROM STextIO IMPORT WriteString, WriteLn;   PROCEDURE Halve(VAR A: CARDINAL); BEGIN A := A / 2; END Halve;   PROCEDURE Double(VAR A: CARDINAL); BEGIN A := 2 * A; END Double;   PROCEDURE IsEven(A: CARDINAL): BOOLEAN; BEGIN RETURN A REM 2 = 0; ...
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...
#zkl
zkl
pow5s:=[1..249].apply("pow",5); // (1^5, 2^5, 3^5 .. 249^5) pow5r:=pow5s.enumerate().apply("reverse").toDictionary(); // [144^5:144, ...] foreach x0,x1,x2,x3 in (249,x0,x1,x2){ sum:=pow5s[x0] + pow5s[x1] + pow5s[x2] + pow5s[x3]; if(pow5r.holds(sum)) println("%d^5 + %d^5 + %d^5 + %d^5 = %d^5" .fmt(...
http://rosettacode.org/wiki/Factorial
Factorial
Definitions   The factorial of   0   (zero)   is defined as being   1   (unity).   The   Factorial Function   of a positive integer,   n,   is defined as the product of the sequence: n,   n-1,   n-2,   ...   1 Task Write a function to return the factorial of a number. Solutions can be iterat...
#Robotic
Robotic
  input string "Enter a number:" set "in" to "('ABS('input')')" if "in" <= 1 then "one" set "result" to 1   : "factorial" set "result" to "('result' * 'in')" dec "in" by 1 if "in" > 1 then "factorial" * "('result')" end   : "one" * "1" end  
http://rosettacode.org/wiki/Even_or_odd
Even or odd
Task Test whether an integer is even or odd. There is more than one way to solve this task: Use the even and odd predicates, if the language provides them. Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd. Divide i by 2. The remainder equals...
#Oforth
Oforth
12 isEven 12 isOdd
http://rosettacode.org/wiki/Even_or_odd
Even or odd
Task Test whether an integer is even or odd. There is more than one way to solve this task: Use the even and odd predicates, if the language provides them. Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd. Divide i by 2. The remainder equals...
#Ol
Ol
  ; 1. Check the least significant bit. (define (even? i) (if (eq? (band i 1) 0) #t #f)) (define (odd? i) (if (eq? (band i 1) 1) #t #f))   (print (if (even? 12345678987654321) "even" "odd")) ; ==> odd (print (if (odd? 12345678987654321) "odd" "even")) ; ==> odd (print (if (even? 1234567898765432) "even" "odd")) ...
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...
#ooRexx
ooRexx
v='' w=' ' if v=='' Then Say 'v contains the empty string'< If length(w)>0 Then Say 'Variable w does not contain the empty string' If w='' Then Say 'this is not a good test'
http://rosettacode.org/wiki/Empty_string
Empty string
Languages may have features for dealing specifically with empty strings (those containing no characters). Task   Demonstrate how to assign an empty string to a variable.   Demonstrate how to check that a string is empty.   Demonstrate how to check that a string is not empty. Other tasks related to string oper...
#OpenEdge.2FProgress
OpenEdge/Progress
DEFINE VARIABLE cc AS CHARACTER.   IF cc > '' THEN MESSAGE 'not empty' VIEW-AS ALERT-BOX. ELSE IF cc = ? THEN MESSAGE 'unknown' VIEW-AS ALERT-BOX. ELSE /* IF cc = '' */ MESSAGE 'empty' VIEW-AS ALERT-BOX.  
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#MATLAB
MATLAB
function [varargout] = emptyprogram(varargin)
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#Maxima
Maxima
block()$
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#MAXScript
MAXScript
 
http://rosettacode.org/wiki/Entropy
Entropy
Task Calculate the Shannon entropy   H   of a given input string. Given the discrete random variable X {\displaystyle X} that is a string of N {\displaystyle N} "symbols" (total characters) consisting of n {\displaystyle n} different characters (n=2 for binary), the Shannon entropy of X in bit...
#XPL0
XPL0
code real RlOut=48, Ln=54; \intrinsic routines string 0; \use zero-terminated strings   func StrLen(A); \Return number of characters in an ASCIIZ string char A; int I; for I:= 0, -1>>1-1 do if A(I) = 0 then return I;   func real Entropy(Str); \Return Shannon entro...
http://rosettacode.org/wiki/Entropy
Entropy
Task Calculate the Shannon entropy   H   of a given input string. Given the discrete random variable X {\displaystyle X} that is a string of N {\displaystyle N} "symbols" (total characters) consisting of n {\displaystyle n} different characters (n=2 for binary), the Shannon entropy of X in bit...
#Zig
Zig
  const std = @import("std"); const math = std.math;   pub fn main() !void { const stdout = std.io.getStdOut().outStream(); try stdout.print("{d:.12}\n", .{H("1223334444")}); }   fn H(s: []const u8) f64 { var counts = [_]u16{0} ** 256; for (s) |ch| counts[ch] += 1;   var h: f64 = 0; for ...
http://rosettacode.org/wiki/Ethiopian_multiplication
Ethiopian multiplication
Ethiopian multiplication is a method of multiplying integers using only addition, doubling, and halving. Method: Take two numbers to be multiplied and write them down at the top of two columns. In the left-hand column repeatedly halve the last number, discarding any remainders, and write the result below the last ...
#Modula-3
Modula-3
MODULE Ethiopian EXPORTS Main;   IMPORT IO, Fmt;   PROCEDURE IsEven(n: INTEGER): BOOLEAN = BEGIN RETURN n MOD 2 = 0; END IsEven;   PROCEDURE Double(n: INTEGER): INTEGER = BEGIN RETURN n * 2; END Double;   PROCEDURE Half(n: INTEGER): INTEGER = BEGIN RETURN n DIV 2; END Half;   PROCEDURE Multiply(...
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...
#ZX_Spectrum_Basic
ZX Spectrum Basic
  1 CLS 2 DIM k(29): DIM q(249) 5 FOR i=4 TO 249: LET q(i)=LN i : NEXT i 6 REM enhancements for the much expanded Spectrum Next: DIM p(248,249) 7 REM FOR j=4TO 248:FOR i=j TO 249:LET p(j,i)=EXP (q(j)-q(i))*5:NEXT i:NEXT j 9 PRINT "slide rule ready" 15 FOR i=0 TO 9: LET k(i)=240+ i : NEXT i 17 FOR i=10 TO 29: LET k(i)=...
http://rosettacode.org/wiki/Factorial
Factorial
Definitions   The factorial of   0   (zero)   is defined as being   1   (unity).   The   Factorial Function   of a positive integer,   n,   is defined as the product of the sequence: n,   n-1,   n-2,   ...   1 Task Write a function to return the factorial of a number. Solutions can be iterat...
#Rockstar
Rockstar
  Factorial takes a number If a number is 0 Give back 1.   Put a number into the first Knock a number down Give back the first times Factorial taking a number  
http://rosettacode.org/wiki/Even_or_odd
Even or odd
Task Test whether an integer is even or odd. There is more than one way to solve this task: Use the even and odd predicates, if the language provides them. Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd. Divide i by 2. The remainder equals...
#OOC
OOC
  // Using the modulo operator even: func (n: Int) -> Bool { (n % 2) == 0 }   // Using bitwise and odd: func (n: Int) -> Bool { (n & 1) == 1 }  
http://rosettacode.org/wiki/Even_or_odd
Even or odd
Task Test whether an integer is even or odd. There is more than one way to solve this task: Use the even and odd predicates, if the language provides them. Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd. Divide i by 2. The remainder equals...
#PARI.2FGP
PARI/GP
odd(n)=n%2;
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...
#PARI.2FGP
PARI/GP
a=""; isEmpty(s)=s=="" \\ Alternately: isEmpty(s)=#s==0 isNonempty(s)=s!="" \\ Alternatively: isNonempty(s)=#s
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...
#Pascal
Pascal
if ($s eq "") { # Test for empty string print "The string is empty"; } if ($s ne "") { # Test for non empty string print "The string is not empty"; }
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#MelonBasic
MelonBasic
 
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#Metafont
Metafont
end
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#Microsoft_Small_Basic
Microsoft Small Basic
 
http://rosettacode.org/wiki/Entropy
Entropy
Task Calculate the Shannon entropy   H   of a given input string. Given the discrete random variable X {\displaystyle X} that is a string of N {\displaystyle N} "symbols" (total characters) consisting of n {\displaystyle n} different characters (n=2 for binary), the Shannon entropy of X in bit...
#zkl
zkl
fcn entropy(text){ text.pump(Void,fcn(c,freq){ c=c.toAsc(); freq[c]+=1; freq } .fp1( (0).pump(256,List,0.0).copy() )) // array[256] of 0.0 .filter() // remove all zero entries from array .apply('/(text.len())) // (num of char)/len .apply(fcn(p){-p*p.log()}) // |p*ln(p)| .sum(0.0)/(2.0)....
http://rosettacode.org/wiki/Entropy
Entropy
Task Calculate the Shannon entropy   H   of a given input string. Given the discrete random variable X {\displaystyle X} that is a string of N {\displaystyle N} "symbols" (total characters) consisting of n {\displaystyle n} different characters (n=2 for binary), the Shannon entropy of X in bit...
#ZX_Spectrum_Basic
ZX Spectrum Basic
10 LET s$="1223334444": LET base=2: LET entropy=0 20 LET sourcelen=LEN s$ 30 DIM t(255) 40 FOR i=1 TO sourcelen 50 LET number= CODE s$(i) 60 LET t(number)=t(number)+1 70 NEXT i 80 PRINT "Char";TAB (6);"Count" 90 FOR i=1 TO 255 100 IF t(i)<>0 THEN PRINT CHR$ i;TAB (6);t(i): LET prop=t(i)/sourcelen: LET entropy=entropy-(...
http://rosettacode.org/wiki/Ethiopian_multiplication
Ethiopian multiplication
Ethiopian multiplication is a method of multiplying integers using only addition, doubling, and halving. Method: Take two numbers to be multiplied and write them down at the top of two columns. In the left-hand column repeatedly halve the last number, discarding any remainders, and write the result below the last ...
#Nemerle
Nemerle
using System; using System.Console;   module Ethiopian { Multiply(x : int, y : int) : int { def halve(a) {a / 2} def doble(a) {a * 2} def isEven(a) {a % 2 == 0} def multiply(p, q) { match(p) { |p when (p < 1) => 0 ...
http://rosettacode.org/wiki/Factorial
Factorial
Definitions   The factorial of   0   (zero)   is defined as being   1   (unity).   The   Factorial Function   of a positive integer,   n,   is defined as the product of the sequence: n,   n-1,   n-2,   ...   1 Task Write a function to return the factorial of a number. Solutions can be iterat...
#Ruby
Ruby
# Recursive def factorial_recursive(n) n.zero? ? 1 : n * factorial_recursive(n - 1) end   # Tail-recursive def factorial_tail_recursive(n, prod = 1) n.zero? ? prod : factorial_tail_recursive(n - 1, prod * n) end   # Iterative with Range#each def factorial_iterative(n) (2...n).each { |i| n *= i } n.zero? ? 1 : n...
http://rosettacode.org/wiki/Even_or_odd
Even or odd
Task Test whether an integer is even or odd. There is more than one way to solve this task: Use the even and odd predicates, if the language provides them. Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd. Divide i by 2. The remainder equals...
#Pascal
Pascal
isOdd := odd(someIntegerNumber);
http://rosettacode.org/wiki/Even_or_odd
Even or odd
Task Test whether an integer is even or odd. There is more than one way to solve this task: Use the even and odd predicates, if the language provides them. Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd. Divide i by 2. The remainder equals...
#Perl
Perl
for(0..10){ print "$_ is ", qw(even odd)[$_ % 2],"\n"; }
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...
#Perl
Perl
if ($s eq "") { # Test for empty string print "The string is empty"; } if ($s ne "") { # Test for non empty string print "The string is not empty"; }
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...
#Phix
Phix
with javascript_semantics string s s = "" -- assign an empty string if length(s)=0 then -- string is empty if s="" then -- string is empty if length(s)!=0 then -- string is not empty if s!="" then -- string is not empty
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#min
min
 
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#MiniScript
MiniScript
 
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#MIPS_Assembly
MIPS Assembly
  .text main: li $v0, 10 syscall  
http://rosettacode.org/wiki/Ethiopian_multiplication
Ethiopian multiplication
Ethiopian multiplication is a method of multiplying integers using only addition, doubling, and halving. Method: Take two numbers to be multiplied and write them down at the top of two columns. In the left-hand column repeatedly halve the last number, discarding any remainders, and write the result below the last ...
#NetRexx
NetRexx
/* NetRexx */ options replace format comments java crossref savelog symbols nobinary   /*REXX program multiplies 2 integers by Ethiopian/Russian peasant method*/ numeric digits 1000 /*handle extremely large integers. */ /*handles zeroes and negative integers.*/ ...
http://rosettacode.org/wiki/Factorial
Factorial
Definitions   The factorial of   0   (zero)   is defined as being   1   (unity).   The   Factorial Function   of a positive integer,   n,   is defined as the product of the sequence: n,   n-1,   n-2,   ...   1 Task Write a function to return the factorial of a number. Solutions can be iterat...
#Run_BASIC
Run BASIC
for i = 0 to 100 print " fctrI(";right$("00";str$(i),2); ") = "; fctrI(i) print " fctrR(";right$("00";str$(i),2); ") = "; fctrR(i) next i end   function fctrI(n) fctrI = 1 if n >1 then for i = 2 To n fctrI = fctrI * i next i end if end function   function fctrR(n) fctrR = 1 if n > 1 then fctrR = n * fct...
http://rosettacode.org/wiki/Even_or_odd
Even or odd
Task Test whether an integer is even or odd. There is more than one way to solve this task: Use the even and odd predicates, if the language provides them. Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd. Divide i by 2. The remainder equals...
#Phix
Phix
with javascript_semantics include mpfr.e mpz z = mpz_init() printf(1," i odd even &&1 rmdr(2)\n") for i=-5 to 5 do mpz_set_si(z,i) printf(1,"%2d: %5t %5t %3d %5d\n",{i,odd(i),even(i),i&&1,remainder(i,2)}) end for
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...
#PHP
PHP
<?php   $str = ''; // assign an empty string to a variable   // check that a string is empty if (empty($str)) { ... }   // check that a string is not empty if (! empty($str)) { ... }   // we could also use the following if ($str == '') { ... } if ($str != '') { ... }   if (strlen($str) == 0) { ... } if (strlen($str) !=...
http://rosettacode.org/wiki/Empty_string
Empty string
Languages may have features for dealing specifically with empty strings (those containing no characters). Task   Demonstrate how to assign an empty string to a variable.   Demonstrate how to check that a string is empty.   Demonstrate how to check that a string is not empty. Other tasks related to string oper...
#Picat
Picat
main => S = "",  % assign an empty string to a variable S == "",  % check that a string is empty, "not empty" != "". % check that a string is not empty
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#.D0.9C.D0.9A-61.2F52
МК-61/52
С/П
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#ML.2FI
ML/I
 
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#MMIX
MMIX
LOC #100 Main TRAP 0,Halt,0 // main (argc, argv) {}
http://rosettacode.org/wiki/Ethiopian_multiplication
Ethiopian multiplication
Ethiopian multiplication is a method of multiplying integers using only addition, doubling, and halving. Method: Take two numbers to be multiplied and write them down at the top of two columns. In the left-hand column repeatedly halve the last number, discarding any remainders, and write the result below the last ...
#Nim
Nim
proc halve(x: int): int = x div 2 proc double(x: int): int = x * 2 proc odd(x: int): bool = x mod 2 != 0   proc ethiopian(x, y: int): int = var x = x var y = y   while x >= 1: if odd(x): result += y x = halve x y = double y   echo ethiopian(17, 34)
http://rosettacode.org/wiki/Factorial
Factorial
Definitions   The factorial of   0   (zero)   is defined as being   1   (unity).   The   Factorial Function   of a positive integer,   n,   is defined as the product of the sequence: n,   n-1,   n-2,   ...   1 Task Write a function to return the factorial of a number. Solutions can be iterat...
#Rust
Rust
fn factorial_recursive (n: u64) -> u64 { match n { 0 => 1, _ => n * factorial_recursive(n-1) } }   fn factorial_iterative(n: u64) -> u64 { (1..=n).product() }   fn main () { for i in 1..10 { println!("{}", factorial_recursive(i)) } for i in 1..10 { println!("{}", ...
http://rosettacode.org/wiki/Even_or_odd
Even or odd
Task Test whether an integer is even or odd. There is more than one way to solve this task: Use the even and odd predicates, if the language provides them. Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd. Divide i by 2. The remainder equals...
#Phixmonti
Phixmonti
-5 5 2 tolist for dup print " " print 2 mod if "Odd" else "Even" endif print nl endfor
http://rosettacode.org/wiki/Even_or_odd
Even or odd
Task Test whether an integer is even or odd. There is more than one way to solve this task: Use the even and odd predicates, if the language provides them. Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd. Divide i by 2. The remainder equals...
#PHP
PHP
  // using bitwise and to check least significant digit echo (2 & 1) ? 'odd' : 'even'; echo (3 & 1) ? 'odd' : 'even';   // using modulo echo (3 % 2) ? 'odd' : 'even'; echo (4 % 2) ? 'odd' : 'even';  
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...
#PicoLisp
PicoLisp
# To assign a variable an empty string: (off String) (setq String "") (setq String NIL)   # To check for an empty string: (or String ..) (ifn String ..) (unless String ..)   # or a non-empty string: (and String ..) (if String ..) (when String ..)
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...
#Pike
Pike
int main() { string s;   if (!s == 1 || sizeof(s) == 0 || s == "") { write("String is empty\n"); } else { write("String not empty\n"); }   return 0; }
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#Modula-2
Modula-2
MODULE Main;   BEGIN END Main.
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#Modula-3
Modula-3
MODULE Main;   BEGIN END Main.
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#MUMPS
MUMPS
http://rosettacode.org/wiki/Ethiopian_multiplication
Ethiopian multiplication
Ethiopian multiplication is a method of multiplying integers using only addition, doubling, and halving. Method: Take two numbers to be multiplied and write them down at the top of two columns. In the left-hand column repeatedly halve the last number, discarding any remainders, and write the result below the last ...
#Objeck
Objeck
  use Collection;   class EthiopianMultiplication { function : Main(args : String[]) ~ Nil { first := IO.Console->ReadString()->ToInt(); second := IO.Console->ReadString()->ToInt(); "----"->PrintLine(); Mul(first, second)->PrintLine(); }   function : native : Mul(first : Int, second : Int) ~ Int {...
http://rosettacode.org/wiki/Factorial
Factorial
Definitions   The factorial of   0   (zero)   is defined as being   1   (unity).   The   Factorial Function   of a positive integer,   n,   is defined as the product of the sequence: n,   n-1,   n-2,   ...   1 Task Write a function to return the factorial of a number. Solutions can be iterat...
#SASL
SASL
  fac 4 where fac 0 = 1 fac n = n * fac (n - 1) ?  
http://rosettacode.org/wiki/Even_or_odd
Even or odd
Task Test whether an integer is even or odd. There is more than one way to solve this task: Use the even and odd predicates, if the language provides them. Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd. Divide i by 2. The remainder equals...
#Picat
Picat
  % Bitwise and is_even_bitwise(I) = cond(I /\ 1 == 0, true, false).   % Modulo is_even_mod(I) = cond(I mod 2 == 0, true, false).   % Remainder is_even_rem(I) = cond(I rem 2 == 0, true, false).   yes_or_no(B) = YN => B = true, YN = "Yes"; B = false, YN = "No".   main :- foreach (I in 2..3) printf("%...
http://rosettacode.org/wiki/Even_or_odd
Even or odd
Task Test whether an integer is even or odd. There is more than one way to solve this task: Use the even and odd predicates, if the language provides them. Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd. Divide i by 2. The remainder equals...
#PicoLisp
PicoLisp
: (bit? 1 3) -> 1 # Odd   : (bit? 1 4) -> NIL # Even
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...
#PL.2FI
PL/I
Dcl s Char(10) Varying; s = ''; /* assign an empty string to a variable. */ if length(s) = 0 then ... /* To test whether a string is empty */ if length(s) > 0 then ... /* to test for a non-empty string */  
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...
#Plain_English
Plain English
To run: Start up. Put "" into a string. If the string is blank, write "Empty!" on the console. If the string is not blank, write "Not empty!" on the console. Wait for the escape key. Shut down.
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#N.2Ft.2Froff
N/t/roff
 
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#Nanoquery
Nanoquery
 
http://rosettacode.org/wiki/Empty_program
Empty program
Task Create the simplest possible program that is still considered "correct."
#Nemerle
Nemerle
null
http://rosettacode.org/wiki/Ethiopian_multiplication
Ethiopian multiplication
Ethiopian multiplication is a method of multiplying integers using only addition, doubling, and halving. Method: Take two numbers to be multiplied and write them down at the top of two columns. In the left-hand column repeatedly halve the last number, discarding any remainders, and write the result below the last ...
#Object_Pascal
Object Pascal
unit Multiplication; interface   function Double(Number: Integer): Integer; function Halve(Number: Integer): Integer; function Even(Number: Integer): Boolean; function Ethiopian(NumberA, NumberB: Integer): Integer;   implementation function Double(Number: Integer): Integer; begin result := Number * 2 end;   ...
http://rosettacode.org/wiki/Factorial
Factorial
Definitions   The factorial of   0   (zero)   is defined as being   1   (unity).   The   Factorial Function   of a positive integer,   n,   is defined as the product of the sequence: n,   n-1,   n-2,   ...   1 Task Write a function to return the factorial of a number. Solutions can be iterat...
#Sather
Sather
class MAIN is   -- recursive fact(a: INTI):INTI is if a < 1.inti then return 1.inti; end; return a * fact(a - 1.inti); end;   -- iterative fact_iter(a:INTI):INTI is s ::= 1.inti; loop s := s * a.downto!(1.inti); end; return s; end;   main is a :INTI := 10.inti; #OUT + fact(a) +...
http://rosettacode.org/wiki/Even_or_odd
Even or odd
Task Test whether an integer is even or odd. There is more than one way to solve this task: Use the even and odd predicates, if the language provides them. Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd. Divide i by 2. The remainder equals...
#Pike
Pike
> int i = 73; > (i&1); Result: 1 > i%2; Result: 1
http://rosettacode.org/wiki/Even_or_odd
Even or odd
Task Test whether an integer is even or odd. There is more than one way to solve this task: Use the even and odd predicates, if the language provides them. Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd. Divide i by 2. The remainder equals...
#PL.2FI
PL/I
i = iand(i,1)
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...
#PowerShell
PowerShell
  [string]$alpha = "abcdefghijklmnopqrstuvwxyz" [string]$empty = "" # or... [string]$empty = [String]::Empty