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http://rosettacode.org/wiki/Playing_cards
Playing cards
Task Create a data structure and the associated methods to define and manipulate a deck of   playing cards. The deck should contain 52 unique cards. The methods must include the ability to:   make a new deck   shuffle (randomize) the deck   deal from the deck   print the current contents of a deck Each card must have a pip value and a suit value which constitute the unique value of the card. Related tasks: Card shuffles Deal cards_for_FreeCell War Card_Game Poker hand_analyser Go Fish
#Scheme
Scheme
(define ranks (quote (ace 2 3 4 5 6 7 8 9 10 jack queen king)))   (define suits (quote (clubs diamonds hearts spades)))   (define new-deck (apply append (map (lambda (suit) (map (lambda (rank) (cons rank suit)) ranks)) suits)))   (define (shuffle deck) (define (remove-card deck index) (if (zero? index) (cdr deck) (cons (car deck) (remove-card (cdr deck) (- index 1))))) (if (null? deck) (list) (let ((index (random (length deck)))) (cons (list-ref deck index) (shuffle (remove-card deck index))))))   (define-syntax deal! (syntax-rules () ((deal! deck hand) (begin (set! hand (cons (car deck) hand)) (set! deck (cdr deck))))))
http://rosettacode.org/wiki/Pi
Pi
Create a program to continually calculate and output the next decimal digit of   π {\displaystyle \pi }   (pi). The program should continue forever (until it is aborted by the user) calculating and outputting each decimal digit in succession. The output should be a decimal sequence beginning   3.14159265 ... Note: this task is about   calculating   pi.   For information on built-in pi constants see Real constants and functions. Related Task Arithmetic-geometric mean/Calculate Pi
#Rust
Rust
use num_bigint::BigInt;   fn main() { calc_pi(); }   fn calc_pi() { let mut q = BigInt::from(1); let mut r = BigInt::from(0); let mut t = BigInt::from(1); let mut k = BigInt::from(1); let mut n = BigInt::from(3); let mut l = BigInt::from(3); let mut first = true; loop { if &q * 4 + &r - &t < &n * &t { print!("{}", n); if first { print!("."); first = false; } let nr = (&r - &n * &t) * 10; n = (&q * 3 + &r) * 10 / &t - &n * 10; q *= 10; r = nr; } else { let nr = (&q * 2 + &r) * &l; let nn = (&q * &k * 7 + 2 + &r * &l) / (&t * &l); q *= &k; t *= &l; l += 2; k += 1; n = nn; r = nr; } } }
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#MATLAB
MATLAB
function perf = isPerfect(n) total = 0; for k = 1:n-1 if ~mod(n, k) total = total+k; end end perf = total == n; end
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#Lambdatalk
Lambdatalk
  {def inject {lambda {:x :a} {if {A.empty? :a} then {A.new {A.new :x}} else {let { {:c {{lambda {:a :b} {A.cons {A.first :a} :b}} :a}} {:d {inject :x {A.rest :a}}} {:e {A.cons :x :a}} } {A.cons :e {A.map :c :d}}}}}} -> inject   {def permut {lambda {:a} {if {A.empty? :a} then {A.new :a} else {let { {:c {{lambda {:a :b} {inject {A.first :a} :b}} :a}} {:d {permut {A.rest :a}}} } {A.reduce A.concat {A.map :c :d}}}}}} -> permut   {permut {A.new 1 2 3}} -> [[1,2,3],[2,1,3],[2,3,1],[1,3,2],[3,1,2],[3,2,1]]   {permut {A.new 1 2 3 4}} -> [[1,2,3,4],[2,1,3,4],[2,3,1,4],[2,3,4,1],[1,3,2,4],[3,1,2,4],[3,2,1,4],[3,2,4,1],[1,3,4,2],[3,1,4,2],[3,4,1,2],[3,4,2,1],[1,2,4,3],[2,1,4,3],[2,4,1,3],[2,4,3,1],[1,4,2,3],[4,1,2,3],[4,2,1,3],[4,2,3,1],[1,4,3,2],[4,1,3,2],[4,3,1,2],[4,3,2,1]]  
http://rosettacode.org/wiki/Playing_cards
Playing cards
Task Create a data structure and the associated methods to define and manipulate a deck of   playing cards. The deck should contain 52 unique cards. The methods must include the ability to:   make a new deck   shuffle (randomize) the deck   deal from the deck   print the current contents of a deck Each card must have a pip value and a suit value which constitute the unique value of the card. Related tasks: Card shuffles Deal cards_for_FreeCell War Card_Game Poker hand_analyser Go Fish
#SenseTalk
SenseTalk
properties cards: [] end properties to initialize set pips to (2, 3, 4, 5, 6, 7, 8, 9, 10, "Jack", "Queen", "King", "Ace") set suits to ("Clubs", "Spades", "Diamonds", "Hearts") repeat for each suit in suits repeat for each pip in pips set card to pip && "of" && suit insert card into my cards end repeat end repeat put "New deck created, number of cards in deck:" && the number of items in my cards end initialize to shuffle sort my cards by random of a million put "Deck shuffled" end shuffle to deal pull from my cards into card put "Card dealt:" && card put "Cards in deck remaining:" && the number of items in my cards end deal to handle asText return my cards joined by return end asText
http://rosettacode.org/wiki/Pi
Pi
Create a program to continually calculate and output the next decimal digit of   π {\displaystyle \pi }   (pi). The program should continue forever (until it is aborted by the user) calculating and outputting each decimal digit in succession. The output should be a decimal sequence beginning   3.14159265 ... Note: this task is about   calculating   pi.   For information on built-in pi constants see Real constants and functions. Related Task Arithmetic-geometric mean/Calculate Pi
#Scala
Scala
object Pi { class PiIterator extends Iterable[BigInt] { var r: BigInt = 0 var q, t, k: BigInt = 1 var n, l: BigInt = 3   def iterator: Iterator[BigInt] = new Iterator[BigInt] { def hasNext = true   def next(): BigInt = { while ((4 * q + r - t) >= (n * t)) { val nr = (2 * q + r) * l val nn = (q * (7 * k) + 2 + (r * l)) / (t * l) q = q * k t = t * l l = l + 2 k = k + 1 n = nn r = nr } val ret = n val nr = 10 * (r - n * t) n = ((10 * (3 * q + r)) / t) - (10 * n) q = q * 10 r = nr ret } } }   def main(args: Array[String]): Unit = { val it = new PiIterator println("" + (it.head) + "." + (it.take(300).mkString)) }   }
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Maxima
Maxima
".."(a, b) := makelist(i, i, a, b)$ infix("..")$   perfectp(n) := is(divsum(n) = 2*n)$   sublist(1 .. 10000, perfectp); /* [6, 28, 496, 8128] */
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#MAXScript
MAXScript
fn isPerfect n = ( local sum = 0 for i in 1 to (n-1) do ( if mod n i == 0 then ( sum += i ) ) sum == n )
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#langur
langur
val .factorial = f if(.x < 2: 1; .x x self(.x - 1))   val .permute = f(.arr) { if not isArray(.arr): throw "expected array"   val .limit = 10 if len(.arr) > .limit: throw $"permutation limit exceeded (currently \.limit;)"   var .elements = .arr var .ordinals = pseries len .elements   val .n = len(.ordinals) var .i, .j   for[.p=[.arr]] of .factorial(len .arr)-1 { .i = .n - 1 .j = .n while .ordinals[.i] > .ordinals[.i+1] { .i -= 1 } while .ordinals[.j] < .ordinals[.i] { .j -= 1 }   .ordinals[.i], .ordinals[.j] = .ordinals[.j], .ordinals[.i] .elements[.i], .elements[.j] = .elements[.j], .elements[.i]   .i += 1 for .j = .n; .i < .j ; .i, .j = .i+1, .j-1 { .ordinals[.i], .ordinals[.j] = .ordinals[.j], .ordinals[.i] .elements[.i], .elements[.j] = .elements[.j], .elements[.i] } .p = more .p, .elements } }   for .e in .permute([1, 3.14, 7]) { writeln .e }
http://rosettacode.org/wiki/Playing_cards
Playing cards
Task Create a data structure and the associated methods to define and manipulate a deck of   playing cards. The deck should contain 52 unique cards. The methods must include the ability to:   make a new deck   shuffle (randomize) the deck   deal from the deck   print the current contents of a deck Each card must have a pip value and a suit value which constitute the unique value of the card. Related tasks: Card shuffles Deal cards_for_FreeCell War Card_Game Poker hand_analyser Go Fish
#Sidef
Sidef
define Pip = <A 2 3 4 5 6 7 8 9 10 J Q K>; define Suit = <♦ ♣ ♥ ♠>;   class Card(pip, suit) { method to_s { pip + suit } }   class Deck(cards=[]) {   method init { cards = gather { Pip.each { |p| Suit.each { |s| take(Card(p, s)) } } } }   method shuffle { cards.shuffle!; }   method deal { cards.shift }; method to_s { cards.join(" ") }; }   var d = Deck(); say "Deck: #{d}";   var top = d.deal; say "Top card: #{top}";   d.shuffle; say "Deck, shuffled: #{d}";
http://rosettacode.org/wiki/Pi
Pi
Create a program to continually calculate and output the next decimal digit of   π {\displaystyle \pi }   (pi). The program should continue forever (until it is aborted by the user) calculating and outputting each decimal digit in succession. The output should be a decimal sequence beginning   3.14159265 ... Note: this task is about   calculating   pi.   For information on built-in pi constants see Real constants and functions. Related Task Arithmetic-geometric mean/Calculate Pi
#Scheme
Scheme
  (import (rnrs))   (define (calc-pi yield) (let loop ((q 1) (r 0) (t 1) (k 1) (n 3) (l 3)) (if (< (- (+ (* 4 q) r) t) (* n t)) (begin (yield n) (loop (* q 10) (* 10 (- r (* n t))) t k (- (div (* 10 (+ (* 3 q) r)) t) (* 10 n)) l)) (begin (loop (* q k) (* (+ (* 2 q) r) l) (* t l) (+ k 1) (div (+ (* q (* 7 k)) 2 (* r l)) (* t l)) (+ l 2))))))   (let ((i 0)) (calc-pi (lambda (d) (display d) (set! i (+ i 1)) (if (= 40 i) (begin (newline) (set! i 0))))))  
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Microsoft_Small_Basic
Microsoft Small Basic
  For n = 2 To 10000 Step 2 VerifyIfPerfect() If isPerfect = 1 Then TextWindow.WriteLine(n) EndIf EndFor   Sub VerifyIfPerfect s = 1 sqrN = Math.SquareRoot(n) If Math.Remainder(n, 2) = 0 Then s = s + 2 + Math.Floor(n / 2) EndIf i = 3 while i <= sqrN - 1 If Math.Remainder(n, i) = 0 Then s = s + i + Math.Floor(n / i) EndIf i = i + 1 EndWhile If i * i = n Then s = s + i EndIf If n = s Then isPerfect = 1 Else isPerfect = 0 EndIf EndSub  
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Modula-2
Modula-2
  MODULE PerfectNumbers;   FROM SWholeIO IMPORT WriteCard; FROM STextIO IMPORT WriteLn; FROM RealMath IMPORT sqrt;   VAR N: CARDINAL;   PROCEDURE IsPerfect(N: CARDINAL): BOOLEAN; VAR S, I: CARDINAL; SqrtN: REAL; BEGIN S := 1; SqrtN := sqrt(FLOAT(N)); IF N REM 2 = 0 THEN S := S + 2 + N / 2; END; I := 3; WHILE FLOAT(I) <= SqrtN - 1.0 DO IF N REM I = 0 THEN S := S + I + N / I; END; I := I + 1; END; IF I * I = N THEN S := S + I; END; RETURN (N = S); END IsPerfect;   BEGIN FOR N := 2 TO 10000 BY 2 DO IF IsPerfect(N) THEN WriteCard(N, 5); WriteLn; END; END; END PerfectNumbers.  
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#LFE
LFE
  (defun permute (('()) '(())) ((l) (lc ((<- x l) (<- y (permute (-- l `(,x))))) (cons x y))))  
http://rosettacode.org/wiki/Playing_cards
Playing cards
Task Create a data structure and the associated methods to define and manipulate a deck of   playing cards. The deck should contain 52 unique cards. The methods must include the ability to:   make a new deck   shuffle (randomize) the deck   deal from the deck   print the current contents of a deck Each card must have a pip value and a suit value which constitute the unique value of the card. Related tasks: Card shuffles Deal cards_for_FreeCell War Card_Game Poker hand_analyser Go Fish
#Smalltalk
Smalltalk
Object subclass: #Card instanceVariableNames: 'thePip theSuit' classVariableNames: 'pips suits' poolDictionaries: '' category: nil !   !Card class methods! initialize suits ifNil: [ suits := 'clubs,hearts,spades,diamonds' subStrings: $, ]. pips ifNil: [ pips := '2,3,4,5,6,7,8,9,10,jack,queen,king,ace' subStrings: $, ] ! new | o | o := super new. ^o ! new: card | o | o := self new. o initWithPip: (card at: 1) andSuit: (card at: 2). ^o !!   !Card class methods ! pips Card initialize. ^pips ! suits Card initialize. ^suits !!   !Card methods! initWithPip: aPip andSuit: aSuit ( (pips includes: aPip asLowercase) & (suits includes: aSuit asLowercase) ) ifTrue: [ thePip := aPip copy. theSuit := aSuit copy ] ifFalse: [ 'Unknown pip or suit' displayOn: stderr . Character nl displayOn: stderr ]. ^self ! asString ^('(%1,%2)' % { thePip . theSuit }) ! display self asString display ! displayNl self display. Character nl display !!     Object subclass: #Deck instanceVariableNames: 'deck' classVariableNames: '' poolDictionaries: '' category: nil !   !Deck class methods ! new |d| d := super new. d init. ^d !!   !Deck methods ! init deck := OrderedCollection new. Card suits do: [ :suit | Card pips do: [ :pip | deck add: (Card new: { pip . suit }) ] ] ! deck ^deck ! shuffle 1 to: self deck size do: [ :i | |r2 o| r2 := Random between: 1 and: self deck size. o := self deck at: i. self deck at: i put: (self deck at: r2). self deck at: r2 put: o ]. ^self ! display self deck do: [ :card | card displayNl ] ! deal ^self deck removeFirst !!   "create a deck, shuffle it, remove the first card and display it" Deck new shuffle deal displayNl.
http://rosettacode.org/wiki/Pi
Pi
Create a program to continually calculate and output the next decimal digit of   π {\displaystyle \pi }   (pi). The program should continue forever (until it is aborted by the user) calculating and outputting each decimal digit in succession. The output should be a decimal sequence beginning   3.14159265 ... Note: this task is about   calculating   pi.   For information on built-in pi constants see Real constants and functions. Related Task Arithmetic-geometric mean/Calculate Pi
#Seed7
Seed7
$ include "seed7_05.s7i"; include "bigint.s7i";   const proc: main is func local var bigInteger: q is 1_; var bigInteger: r is 0_; var bigInteger: t is 1_; var bigInteger: k is 1_; var bigInteger: n is 3_; var bigInteger: l is 3_; var bigInteger: nn is 0_; var bigInteger: nr is 0_; var boolean: first is TRUE; begin while TRUE do if 4_ * q + r - t < n * t then write(n); if first then write("."); first := FALSE; end if; nr := 10_ * (r - n * t); n := 10_ * (3_ * q + r) div t - 10_ * n; q *:= 10_; r := nr; flush(OUT); else nr := (2_ * q + r) * l; nn := (q * (7_ * k + 2_) + r * l) div (t * l); q *:= k; t *:= l; l +:= 2_; incr(k); n := nn; r := nr; end if; end while; end func;
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Nanoquery
Nanoquery
def perf(n) sum = 0 for i in range(1, n - 1) if (n % i) = 0 sum += i end end return sum = n end
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Nim
Nim
import math   proc isPerfect(n: int): bool = var sum: int = 1 for d in 2 .. int(n.toFloat.sqrt): if n mod d == 0: inc sum, d let q = n div d if q != d: inc sum, q result = n == sum   for n in 2..10_000: if n.isPerfect: echo n
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#Liberty_BASIC
Liberty BASIC
  n=3 dim a(n+1) '+1 needed due to bug in LB that checks loop condition ' until (i=0) or (a(i)<a(i+1)) 'before executing i=i-1 in loop body. for i=1 to n: a(i)=i: next do for i=1 to n: print a(i);: next: print i=n do i=i-1 loop until (i=0) or (a(i)<a(i+1)) j=i+1 k=n while j<k 'swap a(j),a(k) tmp=a(j): a(j)=a(k): a(k)=tmp j=j+1 k=k-1 wend if i>0 then j=i+1 while a(j)<a(i) j=j+1 wend 'swap a(i),a(j) tmp=a(j): a(j)=a(i): a(i)=tmp end if loop until i=0  
http://rosettacode.org/wiki/Playing_cards
Playing cards
Task Create a data structure and the associated methods to define and manipulate a deck of   playing cards. The deck should contain 52 unique cards. The methods must include the ability to:   make a new deck   shuffle (randomize) the deck   deal from the deck   print the current contents of a deck Each card must have a pip value and a suit value which constitute the unique value of the card. Related tasks: Card shuffles Deal cards_for_FreeCell War Card_Game Poker hand_analyser Go Fish
#Swift
Swift
  import Foundation   // extend any Indexed collection to be able to shuffle (see http://stackoverflow.com/questions/24026510/how-do-i-shuffle-an-array-in-swift) extension CollectionType where Index == Int { /// Return a copy of `self` with its elements shuffled func shuffle() -> [Generator.Element] { var list = Array(self) list.shuffleInPlace() return list } }   extension MutableCollectionType where Index == Int { /// Shuffle the elements of `self` in-place. mutating func shuffleInPlace() { // empty and single-element collections don't shuffle if count < 2 { return }   for i in 0..<count - 1 { let j = Int(arc4random_uniform(UInt32(count - i))) + i guard i != j else { continue } swap(&self[i], &self[j]) } } }   // now the model structs enum CardColor : Int { case Red case Black } extension CardColor : CustomStringConvertible { var description : String { switch self { case .Red: return "Red" case .Black: return "Black" } } }   enum Suit : Int { case Hearts = 1 case Diamonds case Spades case Clubs   var color : CardColor { switch self { case .Hearts, .Diamonds: return .Red case .Spades, .Clubs: return .Black } } }   enum Pip : Int { case Ace = 1 case Two = 2 case Three = 3 case Four = 4 case Five = 5 case Six = 6 case Seven = 7 case Eight = 8 case Nine = 9 case Ten = 10 case Jack = 11 case Queen = 12 case King = 13 }   struct Card { let pip : Pip let suit : Suit   var isFaceCard : Bool { return pip.rawValue > 10 }   var color : CardColor { return suit.color } } extension Card : Equatable {} func == (l:Card, r:Card) -> Bool { return l.pip == r.pip && l.suit == r.suit } extension Card : CustomStringConvertible { var description : String { return "\(pip) of \(suit)" } }     struct Deck { var cards : [Card]   var count : Int { return cards.count }   init(shuffling:Bool=true) { var startcards = [Card]() for suit in (Suit.Hearts.rawValue...Suit.Clubs.rawValue) { for pip in (Pip.Ace.rawValue...Pip.King.rawValue) { startcards.append(Card(pip: Pip(rawValue: pip)!, suit: Suit(rawValue: suit)!)) } } cards = startcards   if shuffling { shuffle() } }   mutating func shuffle() { cards.shuffleInPlace() }   mutating func deal() -> Card { let out = cards.removeFirst() return out }   } extension Deck : CustomStringConvertible { var description : String { return "\(count) cards: \(cards.description)" } }       // test some cards let kh = Card(pip: .King, suit: .Hearts) let ad = Card(pip: .Ace, suit: .Diamonds) let tc = Card(pip: .Two, suit: .Clubs) let fc = Card(pip: Pip(rawValue:4)!, suit: .Spades)     // create an unshuffled deck var efg = Deck(shuffling: false)     // create a shuffled deck and print its contents var d = Deck() print(d)   // deal three cards d.deal() d.deal() d.deal() d   // deal a couple more cards and check their color let c = d.deal() c.color   let cc = d.deal() cc.color   // deal out the rest of the deck, leaving just one card while d.count > 1 { d.deal() } d   // test equality of a couple cards if kh == Card(pip: Pip.King, suit: Suit.Clubs) { let a = true } else { let a = false }   kh != Card(pip: Pip.King, suit: Suit.Clubs) kh.isFaceCard fc.isFaceCard      
http://rosettacode.org/wiki/Pi
Pi
Create a program to continually calculate and output the next decimal digit of   π {\displaystyle \pi }   (pi). The program should continue forever (until it is aborted by the user) calculating and outputting each decimal digit in succession. The output should be a decimal sequence beginning   3.14159265 ... Note: this task is about   calculating   pi.   For information on built-in pi constants see Real constants and functions. Related Task Arithmetic-geometric mean/Calculate Pi
#Sidef
Sidef
func pi(callback) { var (q, r, t, k, n, l) = (1, 0, 1, 1, 3, 3) loop { if ((4*q + r - t) < n*t) { callback(n) static _dot = callback('.') var nr = 10*(r - n*t) n = ((10*(3*q + r)) // t - 10*n) q *= 10 r = nr } else { var nr = ((2*q + r) * l) var nn = ((q*(7*k + 2) + r*l) // (t*l)) q *= k t *= l l += 2 k += 1 n = nn r = nr } } }   STDOUT.autoflush(true) pi(func(digit){ print digit })
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Objeck
Objeck
bundle Default { class Test { function : Main(args : String[]) ~ Nil { "Perfect numbers from 1 to 33550337:"->PrintLine(); for(num := 1 ; num < 33550337; num += 1;) { if(IsPerfect(num)) { num->PrintLine(); }; }; }   function : native : IsPerfect(number : Int) ~ Bool { sum := 0 ; for(i := 1; i < number; i += 1;) { if (number % i = 0) { sum += i; }; };   return sum = number; } } }
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#Lobster
Lobster
  // Lobster implementation of the (very fast) Go example // http://rosettacode.org/wiki/Permutations#Go // implementing the plain changes (bell ringers) algorithm, using a recursive function // https://en.wikipedia.org/wiki/Steinhaus–Johnson–Trotter_algorithm   def permr(s, f): if s.length == 0: f(s) return def rc(np: int): if np == 1: f(s) return let np1 = np - 1 let pp = s.length - np1 rc(np1) // recurs prior swaps var i = pp while i > 0: // swap s[i], s[i-1] let t = s[i] s[i] = s[i-1] s[i-1] = t rc(np1) // recurs swap i -= 1 let w = s[0] for(pp): s[_] = s[_+1] s[pp] = w rc(s.length)   // Heap's recursive method https://en.wikipedia.org/wiki/Heap%27s_algorithm   def permh(s, f): def rc(k: int): if k <= 1: f(s) else: // Generate permutations with kth unaltered // Initially k == length(s) rc(k-1) // Generate permutations for kth swapped with each k-1 initial for(k-1) i: // Swap choice dependent on parity of k (even or odd) // zero-indexed, the kth is at k-1 if (k & 1) == 0: let t = s[i] s[i] = s[k-1] s[k-1] = t else: let t = s[0] s[0] = s[k-1] s[k-1] = t rc(k-1) rc(s.length)   // iterative Boothroyd method   import std   def permi(xs, f): var d = 1 let c = map(xs.length): 0 f(xs) while true: while d > 1: d -= 1 c[d] = 0 while c[d] >= d: d += 1 if d >= xs.length: return let i = if (d & 1) == 1: c[d] else: 0 let t = xs[i] xs[i] = xs[d] xs[d] = t f(xs) c[d] = c[d] + 1   // next lexicographical permutation // to get all permutations the initial input `a` must be in sorted order // returns false when input `a` is in reverse sorted order   def next_lex_perm(a): def swap(i, j): let t = a[i] a[i] = a[j] a[j] = t let n = a.length /* 1. Find the largest index k such that a[k] < a[k + 1]. If no such index exists, the permutation is the last permutation. */ var k = n - 1 while k > 0 and a[k-1] >= a[k]: k-- if k == 0: return false k -= 1 /* 2. Find the largest index l such that a[k] < a[l]. Since k + 1 is such an index, l is well defined */ var l = n - 1 while a[l] <= a[k]: l-- /* 3. Swap a[k] with a[l] */ swap(k, l) /* 4. Reverse the sequence from a[k + 1] to the end */ k += 1 l = n - 1 while l > k: swap(k, l) l -= 1 k += 1 return true   var se = [0, 1, 2, 3] //, 4, 5, 6, 7, 8, 9, 10]   print "Iterative lexicographical permuter"   print se while next_lex_perm(se): print se   print "Recursive plain changes iterator"   se = [0, 1, 2, 3]   permr(se): print(_)   print "Recursive Heap\'s iterator"   se = [0, 1, 2, 3]   permh(se): print(_)   print "Iterative Boothroyd iterator"   se = [0, 1, 2, 3]   permi(se): print(_)  
http://rosettacode.org/wiki/Playing_cards
Playing cards
Task Create a data structure and the associated methods to define and manipulate a deck of   playing cards. The deck should contain 52 unique cards. The methods must include the ability to:   make a new deck   shuffle (randomize) the deck   deal from the deck   print the current contents of a deck Each card must have a pip value and a suit value which constitute the unique value of the card. Related tasks: Card shuffles Deal cards_for_FreeCell War Card_Game Poker hand_analyser Go Fish
#Tcl
Tcl
package require Tcl 8.5   namespace eval playing_cards { variable deck #variable suits {C D H S} variable suits {\u2663 \u2662 \u2661 \u2660} variable pips {2 3 4 5 6 7 8 9 10 J Q K A}   proc new_deck {} { variable deck set deck [list] for {set i 0} {$i < 52} {incr i} { lappend deck $i } }   proc shuffle {} { variable deck # shuffle in place for {set i 51} {$i > 0} {incr i -1} { set n [expr {int($i * rand())}] set card [lindex $deck $n] lset deck $n [lindex $deck $i] lset deck $i $card } }   proc deal {{num 1}} { variable deck incr num -1 set cards [lrange $deck 0 $num] set deck [lreplace $deck 0 $num] return $cards }   proc card2string {card} { variable suits variable pips set suit [expr {$card / 13}] set pip [expr {$card % 13}] return [format "%2s %s" [lindex $pips $pip] [lindex $suits $suit]] }   proc print {cards args} { array set opts [concat -sort false $args] if {$opts(-sort)} { set cards [lsort -integer $cards] } foreach card $cards { puts [card2string $card] } }   proc print_deck {} { variable deck print $deck } }   playing_cards::new_deck playing_cards::shuffle set hand [playing_cards::deal 5] puts "my hand:" playing_cards::print $hand -sort true puts "\nthe deck:" playing_cards::print_deck
http://rosettacode.org/wiki/Pi
Pi
Create a program to continually calculate and output the next decimal digit of   π {\displaystyle \pi }   (pi). The program should continue forever (until it is aborted by the user) calculating and outputting each decimal digit in succession. The output should be a decimal sequence beginning   3.14159265 ... Note: this task is about   calculating   pi.   For information on built-in pi constants see Real constants and functions. Related Task Arithmetic-geometric mean/Calculate Pi
#Simula
Simula
CLASS BIGNUM; BEGIN   BOOLEAN PROCEDURE TISZERO(T); TEXT T; TISZERO := T = "0";   TEXT PROCEDURE TSHL(T); TEXT T; TSHL :- IF TISZERO(T) THEN T ELSE T & "0";   TEXT PROCEDURE TSHR(T); TEXT T; TSHR :- IF T.LENGTH = 1 THEN "0" ELSE T.SUB(1, T.LENGTH - 1);   INTEGER PROCEDURE TSIGN(T); TEXT T; TSIGN := IF TISZERO(T) THEN 0 ELSE IF T.SUB(1, 1) = "-" THEN -1 ELSE 1;   TEXT PROCEDURE TABS(T); TEXT T; TABS :- IF TSIGN(T) < 0 THEN T.SUB(2, T.LENGTH - 1) ELSE T;   TEXT PROCEDURE TNEGATE(T); TEXT T; TNEGATE :- IF TSIGN(T) <= 0 THEN TABS(T) ELSE ("-" & T);   TEXT PROCEDURE TREVERSE(T); TEXT T; BEGIN INTEGER I, J; I := 1; J := T.LENGTH; WHILE I < J DO BEGIN CHARACTER C1, C2; T.SETPOS(I); C1 := T.GETCHAR; T.SETPOS(J); C2 := T.GETCHAR; T.SETPOS(I); T.PUTCHAR(C2); T.SETPOS(J); T.PUTCHAR(C1); I := I + 1; J := J - 1; END; TREVERSE :- T; END TREVERSE;   INTEGER PROCEDURE TCMPUNSIGNED(A, B); TEXT A, B; BEGIN INTEGER ALEN, BLEN, RESULT; ALEN := A.LENGTH; BLEN := B.LENGTH; IF ALEN < BLEN THEN RESULT := -1 ELSE IF ALEN > BLEN THEN RESULT := 1 ELSE BEGIN INTEGER CMP, I; BOOLEAN DONE; A.SETPOS(1); B.SETPOS(1); I := 1; WHILE I <= ALEN AND NOT DONE DO BEGIN I := I + 1; CMP := RANK(A.GETCHAR) - RANK(B.GETCHAR); IF NOT (CMP = 0) THEN DONE := TRUE; END; RESULT := CMP; END; TCMPUNSIGNED := RESULT; END TCMPUNSIGNED;   INTEGER PROCEDURE TCMP(A, B); TEXT A, B; BEGIN BOOLEAN ANEG, BNEG; ANEG := TSIGN(A) < 0; BNEG := TSIGN(B) < 0; IF ANEG AND BNEG THEN TCMP := -TCMPUNSIGNED(TABS(A), TABS(B)) ELSE IF NOT ANEG AND BNEG THEN TCMP := 1 ELSE IF ANEG AND NOT BNEG THEN TCMP := -1 ELSE TCMP := TCMPUNSIGNED(A, B); END TCMP;   TEXT PROCEDURE TADDUNSIGNED(A, B); TEXT A, B; BEGIN INTEGER CARRY, I, J; TEXT BF; I := A.LENGTH; J := B.LENGTH; BF :- BLANKS(MAX(I, J) + 1); WHILE I >= 1 OR J >= 1 DO BEGIN INTEGER X, Y, Z; IF I >= 1 THEN BEGIN A.SETPOS(I); I := I - 1; X := RANK(A.GETCHAR) - RANK('0'); END; IF J >= 1 THEN BEGIN B.SETPOS(J); J := J - 1; Y := RANK(B.GETCHAR) - RANK('0'); END; Z := X + Y + CARRY; IF Z < 10 THEN BEGIN BF.PUTCHAR(CHAR(Z + RANK('0'))); CARRY := 0; END ELSE BEGIN BF.PUTCHAR(CHAR(MOD(Z, 10) + RANK('0'))); CARRY := 1; END; END; IF CARRY > 0 THEN BF.PUTCHAR(CHAR(CARRY + RANK('0'))); BF :- TREVERSE(BF.STRIP); TADDUNSIGNED :- BF; END TADDUNSIGNED;   TEXT PROCEDURE TADD(A, B); TEXT A, B; BEGIN BOOLEAN ANEG, BNEG; ANEG := TSIGN(A) < 0; BNEG := TSIGN(B) < 0; IF NOT ANEG AND BNEG THEN  ! (+7)+(-5) = (7-5) = 2 ; TADD :- TSUBUNSIGNED(A, TABS(B)) ELSE IF ANEG AND NOT BNEG THEN  ! (-7)+(+5) = (5-7) = -2 ; TADD :- TSUBUNSIGNED(B, TABS(A)) ELSE IF ANEG AND BNEG THEN  ! (-7)+(-5) = -(7+5) = -12 ; TADD :- TNEGATE(TADDUNSIGNED(TABS(A), TABS(B))) ELSE  ! (+7)+(+5) = (7+5) = 12 ; TADD :- TADDUNSIGNED(A, B); END TADD;   TEXT PROCEDURE TSUBUNSIGNED(A, B); TEXT A, B; BEGIN INTEGER I, J, CARRY; I := A.LENGTH; J := B.LENGTH; IF I < J OR I = J AND A < B THEN TSUBUNSIGNED :- TNEGATE(TSUBUNSIGNED(B, A)) ELSE BEGIN TEXT BF; BF :- BLANKS(MAX(I, J) + 1); WHILE I >= 1 OR J >= 1 DO BEGIN INTEGER X, Y, Z; IF I >= 1 THEN BEGIN A.SETPOS(I); I := I - 1; X := RANK(A.GETCHAR) - RANK('0'); END; IF J >= 1 THEN BEGIN B.SETPOS(J); J := J - 1; Y := RANK(B.GETCHAR) - RANK('0'); END; Z := X - Y - CARRY; IF Z >= 0 THEN BEGIN BF.PUTCHAR(CHAR(RANK('0') + Z)); CARRY := 0; END ELSE BEGIN BF.PUTCHAR(CHAR(RANK('0') + MOD(10 + Z, 10))); CARRY := 1; ! (Z / 10); END; END; BF :- BF.STRIP; BF :- TREVERSE(BF); BF.SETPOS(1); WHILE BF.LENGTH > 1 AND THEN BF.GETCHAR = '0' DO BEGIN BF :- BF.SUB(2, BF.LENGTH - 1); BF.SETPOS(1); END; TSUBUNSIGNED :- BF; END; END TSUBUNSIGNED;   TEXT PROCEDURE TSUB(A, B); TEXT A, B; BEGIN BOOLEAN ANEG, BNEG; ANEG := TSIGN(A) < 0; BNEG := TSIGN(B) < 0; IF ANEG AND BNEG THEN  ! (-7)-(-5) = -(7-5) = -2 ; TSUB :- TNEGATE(TSUBUNSIGNED(TABS(A), TABS(B))) ELSE IF NOT ANEG AND BNEG THEN  ! (+7)-(-5) = (7+5) = 12 ; TSUB :- TADDUNSIGNED(A, TABS(B)) ELSE IF ANEG AND NOT BNEG THEN  ! (-7)-(+5) = -(7+5) = -12 ; TSUB :- TNEGATE(TADDUNSIGNED(TABS(A), B)) ELSE  ! (+7)-(+5) = (7-5) = 2 ; TSUB :- TSUBUNSIGNED(A, B); END TSUB;   TEXT PROCEDURE TMULUNSIGNED(A, B); TEXT A, B; BEGIN INTEGER ALEN, BLEN; ALEN := A.LENGTH; BLEN := B.LENGTH; IF ALEN < BLEN THEN TMULUNSIGNED :- TMULUNSIGNED(B, A) ELSE BEGIN TEXT PRODUCT; INTEGER J; PRODUCT :- "0"; FOR J := 1 STEP 1 UNTIL BLEN DO BEGIN TEXT PART; INTEGER I, Y, CARRY; B.SETPOS(J); Y := RANK(B.GETCHAR) - RANK('0'); PART :- BLANKS(ALEN + BLEN + 1); PART.SETPOS(1); FOR I := ALEN STEP -1 UNTIL 1 DO BEGIN INTEGER X, Z; A.SETPOS(I); X := RANK(A.GETCHAR) - RANK('0'); Z := X * Y + CARRY; IF Z < 10 THEN BEGIN PART.PUTCHAR(CHAR(RANK('0') + Z)); CARRY := 0; END ELSE BEGIN PART.PUTCHAR(CHAR(RANK('0') + MOD(Z, 10))); CARRY := Z // 10; END; END; IF CARRY > 0 THEN PART.PUTCHAR(CHAR(RANK('0') + CARRY)); PART :- PART.SUB(1, PART.POS - 1); PART :- TREVERSE(PART); PART.SETPOS(1); WHILE PART.LENGTH > 1 AND THEN PART.GETCHAR = '0' DO BEGIN PART :- PART.SUB(2, PART.LENGTH - 1); PART.SETPOS(1); END; PRODUCT :- TADDUNSIGNED(TSHL(PRODUCT), PART); END; TMULUNSIGNED :- PRODUCT; END; END TMULUNSIGNED;   TEXT PROCEDURE TMUL(A, B); TEXT A, B; BEGIN BOOLEAN ANEG, BNEG; ANEG := TSIGN(A) < 0; BNEG := TSIGN(B) < 0; IF ANEG AND BNEG THEN  ! (-7)*(-5) = (7*5) => 35 ; TMUL :- TMULUNSIGNED(TABS(A), TABS(B)) ELSE IF NOT ANEG AND BNEG THEN  ! (+7)*(-5) = -(7*5) => -35 ; TMUL :- TNEGATE(TMULUNSIGNED(A, TABS(B))) ELSE IF ANEG AND NOT BNEG THEN  ! (-7)*(+5) = -(7*5) => -35 ; TMUL :- TNEGATE(TMULUNSIGNED(TABS(A), B)) ELSE  ! (+7)*(+5) = (7*5) => 35 ; TMUL :- TMULUNSIGNED(A, B); END TMUL;   CLASS DIVMOD(DIV,MOD); TEXT DIV,MOD;;   REF(DIVMOD) PROCEDURE TDIVMODUNSIGNED(A, B); TEXT A, B; BEGIN INTEGER CC; REF(DIVMOD) RESULT; IF TISZERO(B) THEN ERROR("DIVISION BY ZERO"); CC := TCMPUNSIGNED(A, B); IF CC < 0 THEN RESULT :- NEW DIVMOD("0", A) ELSE IF CC = 0 THEN RESULT :- NEW DIVMOD("1", "0") ELSE BEGIN INTEGER ALEN, BLEN, AIDX; TEXT Q, R; ALEN := A.LENGTH; BLEN := B.LENGTH; Q :- BLANKS(ALEN); Q.SETPOS(1); R :- BLANKS(ALEN); R.SETPOS(1); R := A.SUB(1, BLEN - 1); R.SETPOS(BLEN); FOR AIDX := BLEN STEP 1 UNTIL ALEN DO BEGIN INTEGER COUNT; BOOLEAN DONE; IF TISZERO(R.STRIP) THEN R.SETPOS(1); A.SETPOS(AIDX); R.PUTCHAR(A.GETCHAR); WHILE NOT DONE DO BEGIN TEXT DIFF; DIFF :- TSUBUNSIGNED(R.STRIP, B); IF TSIGN(DIFF) < 0 THEN DONE := TRUE ELSE BEGIN R := DIFF; R.SETPOS(DIFF.LENGTH + 1); COUNT := COUNT + 1; END; END; IF (NOT (COUNT = 0)) OR (NOT (Q.POS = 1)) THEN Q.PUTCHAR(CHAR(COUNT + RANK('0'))); END; RESULT :- NEW DIVMOD(Q.STRIP, R.STRIP); END; TDIVMODUNSIGNED :- RESULT; END TDIVMODUNSIGNED;   REF(DIVMOD) PROCEDURE TDIVMOD(A, B); TEXT A, B; BEGIN BOOLEAN ANEG, BNEG; REF(DIVMOD) RESULT; ANEG := TSIGN(A) < 0; BNEG := TSIGN(B) < 0; IF ANEG AND BNEG THEN BEGIN RESULT :- TDIVMOD(TABS(A), TABS(B)); RESULT.MOD :- TNEGATE(RESULT.MOD); END ELSE IF NOT ANEG AND BNEG THEN BEGIN RESULT :- TDIVMOD(A, TABS(B)); RESULT.DIV :- TNEGATE(RESULT.DIV); END ELSE IF ANEG AND NOT BNEG THEN BEGIN RESULT :- TDIVMOD(TABS(A), B); RESULT.DIV :- TNEGATE(RESULT.DIV); RESULT.MOD :- TNEGATE(RESULT.MOD); END ELSE RESULT :- TDIVMODUNSIGNED(A, B); TDIVMOD :- RESULT; END TDIVMOD;   TEXT PROCEDURE TDIV(A, B); TEXT A, B; TDIV :- TDIVMOD(A, B).DIV;   TEXT PROCEDURE TMOD(A, B); TEXT A, B; TMOD :- TDIVMOD(A, B).MOD;   END BIGNUM;
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#OCaml
OCaml
let perf n = let sum = ref 0 in for i = 1 to n-1 do if n mod i = 0 then sum := !sum + i done; !sum = n
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Oforth
Oforth
: isPerfect(n) | i | 0 n 2 / loop: i [ n i mod ifZero: [ i + ] ] n == ;
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#Logtalk
Logtalk
:- object(list).   :- public(permutation/2).   permutation(List, Permutation) :- same_length(List, Permutation), permutation2(List, Permutation).   permutation2([], []). permutation2(List, [Head| Tail]) :- select(Head, List, Remaining), permutation2(Remaining, Tail).   same_length([], []). same_length([_| Tail1], [_| Tail2]) :- same_length(Tail1, Tail2).   select(Head, [Head| Tail], Tail). select(Head, [Head2| Tail], [Head2| Tail2]) :- select(Head, Tail, Tail2).   :- end_object.
http://rosettacode.org/wiki/Playing_cards
Playing cards
Task Create a data structure and the associated methods to define and manipulate a deck of   playing cards. The deck should contain 52 unique cards. The methods must include the ability to:   make a new deck   shuffle (randomize) the deck   deal from the deck   print the current contents of a deck Each card must have a pip value and a suit value which constitute the unique value of the card. Related tasks: Card shuffles Deal cards_for_FreeCell War Card_Game Poker hand_analyser Go Fish
#VBScript
VBScript
  class playingcard dim suit dim pips end class   class carddeck private suitnames private pipnames private cardno private deck(52) private nTop   sub class_initialize dim suit dim pips suitnames = split("H,D,C,S",",") pipnames = split("A,2,3,4,5,6,7,8,9,10,J,Q,K",",") cardno = 0   for suit = 1 to 4 for pips = 1 to 13 set deck(cardno) = new playingcard deck(cardno).suit = suitnames(suit-1) deck(cardno).pips = pipnames(pips-1) cardno = cardno + 1 next next nTop = 0 end sub   public sub showdeck dim a redim a(51-nTop) for i = nTop to 51 a(i) = deck(i).pips & deck(i).suit next wscript.echo join( a, ", ") end sub   public sub shuffle dim r randomize timer for i = nTop to 51 r = int( rnd * ( 52 - nTop ) ) if r <> i then objswap deck(i),deck(r) end if next end sub   public function deal() set deal = deck( nTop ) nTop = nTop + 1 end function   public property get cardsRemaining cardsRemaining = 52 - nTop end property   private sub objswap( a, b ) dim tmp set tmp = a set a = b set b = tmp end sub end class  
http://rosettacode.org/wiki/Pi
Pi
Create a program to continually calculate and output the next decimal digit of   π {\displaystyle \pi }   (pi). The program should continue forever (until it is aborted by the user) calculating and outputting each decimal digit in succession. The output should be a decimal sequence beginning   3.14159265 ... Note: this task is about   calculating   pi.   For information on built-in pi constants see Real constants and functions. Related Task Arithmetic-geometric mean/Calculate Pi
#Tailspin
Tailspin
  use 'java:java.math' stand-alone   def zero: 0 -> math/BigInteger::valueOf; def one: 1 -> math/BigInteger::valueOf; def two: 2 -> math/BigInteger::valueOf; def three: 3 -> math/BigInteger::valueOf; def four: 4 -> math/BigInteger::valueOf; def seven: 7 -> math/BigInteger::valueOf; def ten: 10 -> math/BigInteger::valueOf;   templates g&{q:, r:, t:, k:, n:, l:} def u: $four -> q::multiply -> r::add; def nt: $n -> t::multiply; $ -> # when <?($t -> u::subtract <..~$nt>)> do $n -> !OUT::write $ -> \(<=1> $!\) -> '.' -> !OUT::write def v: $three -> q::multiply -> r::add -> ten::multiply; def quot: $t -> v::divide; 0 -> g&{q: $ten -> q::multiply, r: $nt -> r::subtract -> ten::multiply, t: $t, k: $k, n: $ten -> n::multiply -> quot::subtract, l: $l } ! otherwise def tl: $t -> l::multiply; def rl: $r -> l::multiply; def term: $q -> seven::multiply -> k::multiply -> two::add -> rl::add; $ -> g&{q: $q -> k::multiply, r: $two -> q::multiply -> r::add -> l::multiply, t: $tl, k: $k -> one::add, n: $tl -> term::divide, l: $l -> two::add} ! end g   1 -> g&{q:$one, r:$zero, t:$one, k:$one, n:$three, l:$three} -> !VOID  
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#ooRexx
ooRexx
-- first perfect number over 10000 is 33550336...let's not be crazy loop i = 1 to 10000 if perfectNumber(i) then say i "is a perfect number" end   ::routine perfectNumber use strict arg n   sum = 0   -- the largest possible factor is n % 2, so no point in -- going higher than that loop i = 1 to n % 2 if n // i == 0 then sum += i end   return sum = n
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#Lua
Lua
  local function permutation(a, n, cb) if n == 0 then cb(a) else for i = 1, n do a[i], a[n] = a[n], a[i] permutation(a, n - 1, cb) a[i], a[n] = a[n], a[i] end end end   --Usage local function callback(a) print('{'..table.concat(a, ', ')..'}') end permutation({1,2,3}, 3, callback)  
http://rosettacode.org/wiki/Playing_cards
Playing cards
Task Create a data structure and the associated methods to define and manipulate a deck of   playing cards. The deck should contain 52 unique cards. The methods must include the ability to:   make a new deck   shuffle (randomize) the deck   deal from the deck   print the current contents of a deck Each card must have a pip value and a suit value which constitute the unique value of the card. Related tasks: Card shuffles Deal cards_for_FreeCell War Card_Game Poker hand_analyser Go Fish
#Vedit_macro_language
Vedit macro language
// Playing Cards, main program   Call("CREATE_DECK") Call("SHUFFLE_DECK") #21 = Buf_Switch(Buf_Free) // #21 = players hand, 1st player #1 = 5; Call("DEAL_CARDS") // deal 5 cards to player 1 #22 = Buf_Switch(Buf_Free) // #22 = players hand, 2nd player #1 = 5; Call("DEAL_CARDS") // deal 5 cards to player 2 Buf_Switch(#10) BOF // display the deck Return   /////////////////////////////////////////////////////////////////////////// // // Create a deck into a new edit buffer. One text line for each card. // :CREATE_DECK: #10 = Buf_Switch(Buf_Free) // Buffer @(#10) = the deck   RS(1, "Diamonds") RS(2, "Spades") RS(3, "Hearts") RS(4, "Clubs")   RS(11, " Jack") RS(12, "Queen") RS(13, " King") RS(14, " Ace")   for (#1=1; #1<5; #1++) { for (#2=2; #2<15; #2++) { if (#2 < 11) { Num_Ins(#2, NOCR) // pip (2 to 10) as numeric } else { IT(@(#2)) // pip (11 to 14) as a word } IT(" of ") IT(@(#1)) IN // suit } } Return   /////////////////////////////////////////////////////////////////////////// // // Shuffle the deck using Fisher-Yates algorithm // :SHUFFLE_DECK: Buf_Switch(#10) // the deck #90 = Time_Tick // seed for random number generator #91 = 51 // random numbers in range 0 to 50 for (#1=1; #1<52; #1++) { Call("RANDOM") Goto_Line(Return_Value+1) Block_Copy(#1, #1, LINESET+DELETE) Reg_Copy(9, 1, DELETE) Goto_Line(#1) Reg_Ins(9) } Return   //-------------------------------------------------------------- // Generate random numbers in range 0 <= Return_Value < #91 // #90 = Seed (0 to 0x7fffffff) // #91 = Scaling (0 to 0x10000)   :RANDOM: #92 = 0x7fffffff / 48271 #93 = 0x7fffffff % 48271 #90 = (48271 * (#90 % #92) - #93 * (#90 / #92)) & 0x7fffffff Return ((#90 & 0xffff) * #91 / 0x10000)     /////////////////////////////////////////////////////////////////////////// // // Deal #1 cards: move the cards from deck to current edit buffer // :DEAL_CARDS: #11 = Buf_Num // this buffer (players hand) Buf_Switch(#10) // the deck BOF Reg_Copy(9, #1, DELETE) // pull the first #1 cards from the deck Buf_Switch(#11) // players hand Reg_ins(9) // insert the cards here Return
http://rosettacode.org/wiki/Pi
Pi
Create a program to continually calculate and output the next decimal digit of   π {\displaystyle \pi }   (pi). The program should continue forever (until it is aborted by the user) calculating and outputting each decimal digit in succession. The output should be a decimal sequence beginning   3.14159265 ... Note: this task is about   calculating   pi.   For information on built-in pi constants see Real constants and functions. Related Task Arithmetic-geometric mean/Calculate Pi
#Tcl
Tcl
package require Tcl 8.6   # http://www.cut-the-knot.org/Curriculum/Algorithms/SpigotForPi.shtml # http://www.mathpropress.com/stan/bibliography/spigot.pdf proc piDigitsBySpigot n { yield [info coroutine] set A [lrepeat [expr {int(floor(10*$n/3.)+1)}] 2] set Alen [llength $A] set predigits {} while 1 { set carry 0 for {set i $Alen} {[incr i -1] > 0} {} { lset A $i [expr { [set val [expr {[lindex $A $i] * 10 + $carry}]] % [set modulo [expr {2*$i + 1}]] }] set carry [expr {$val / $modulo * $i}] } lset A 0 [expr {[set val [expr {[lindex $A 0]*10 + $carry}]] % 10}] set predigit [expr {$val / 10}] if {$predigit < 9} { foreach p $predigits {yield $p} set predigits [list $predigit] } elseif {$predigit == 9} { lappend predigits $predigit } else { foreach p $predigits {yield [incr p]} set predigits [list 0] } } }
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Oz
Oz
declare fun {IsPerfect N} fun {IsNFactor I} N mod I == 0 end Factors = {Filter {List.number 1 N-1 1} IsNFactor} in {Sum Factors} == N end   fun {Sum Xs} {FoldL Xs Number.'+' 0} end in {Show {Filter {List.number 1 10000 1} IsPerfect}} {Show {IsPerfect 33550336}}
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#M2000_Interpreter
M2000 Interpreter
  Module Checkit { Global a$ Document a$ Module Permutations (s){ Module Level (n, s, h) { If n=1 then { while Len(s) { m1=each(h) while m1 { Print Array$(m1);" "; } Print Array$(S) ToClipBoard() s=cdr(s) } } Else { for i=1 to len(s) { call Level n-1, cdr(s), cons(h, car(s)) s=cons(cdr(s), car(s)) } } Sub ToClipBoard() local m=each(h) Local b$="" While m { b$+=If$(Len(b$)<>0->" ","")+Array$(m)+" " } b$+=If$(Len(b$)<>0->" ","")+Array$(s,0)+" "+{ } a$<=b$ ' assign to global need <= End Sub } If len(s)=0 then Error Head=(,) Call Level Len(s), s, Head } Clear a$ Permutations (1,2,3,4) Permutations (100, 200, 500) Permutations ("A", "B", "C","D") Permutations ("DOG", "CAT", "BAT") ClipBoard a$ } Checkit  
http://rosettacode.org/wiki/Playing_cards
Playing cards
Task Create a data structure and the associated methods to define and manipulate a deck of   playing cards. The deck should contain 52 unique cards. The methods must include the ability to:   make a new deck   shuffle (randomize) the deck   deal from the deck   print the current contents of a deck Each card must have a pip value and a suit value which constitute the unique value of the card. Related tasks: Card shuffles Deal cards_for_FreeCell War Card_Game Poker hand_analyser Go Fish
#Wren
Wren
import "random" for Random   var FACES = "23456789TJQKA" var SUITS = "shdc"   var createDeck = Fn.new { var cards = [] SUITS.each { |suit| FACES.each { |face| cards.add("%(face)%(suit)") } } return cards }   var dealTopDeck = Fn.new { |deck, n| deck.take(n).toList }   var dealBottomDeck = Fn.new { |deck, n| deck[-n..-1][-1..0] }   var printDeck = Fn.new { |deck| for (i in 0...deck.count) { System.write("%(deck[i]) ") if ((i + 1) % 13 == 0 || i == deck.count - 1) System.print() } }   var deck = createDeck.call() System.print("After creation, deck consists of:") printDeck.call(deck) Random.new().shuffle(deck) System.print("\nAfter shuffling, deck consists of:") printDeck.call(deck) var dealtTop = dealTopDeck.call(deck, 10) System.print("\nThe 10 cards dealt from the top of the deck are:") printDeck.call(dealtTop) var dealtBottom = dealBottomDeck.call(deck, 10) System.print("\nThe 10 cards dealt from the bottom of the deck are:") printDeck.call(dealtBottom)
http://rosettacode.org/wiki/Pi
Pi
Create a program to continually calculate and output the next decimal digit of   π {\displaystyle \pi }   (pi). The program should continue forever (until it is aborted by the user) calculating and outputting each decimal digit in succession. The output should be a decimal sequence beginning   3.14159265 ... Note: this task is about   calculating   pi.   For information on built-in pi constants see Real constants and functions. Related Task Arithmetic-geometric mean/Calculate Pi
#TypeScript
TypeScript
type AnyWriteableObject={write:((textToOutput:string)=>any)};   function calcPi(pipe:AnyWriteableObject) { let q = 1n, r=0n, t=1n, k=1n, n=3n, l=3n; while (true) { if (q * 4n + r - t < n* t) { pipe.write(n.toString()); let nr = (r - n * t) * 10n; n = (q * 3n + r) * 10n / t - n * 10n ; q = q * 10n; r = nr; } else { let nr = (q * 2n + r) * l; let nn = (q * k * 7n + 2n + r * l) / (t * l); q = q * k; t = t * l; l = l + 2n; k = k + 1n; n = nn; r = nr; } } }   calcPi(process.stdout);
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#PARI.2FGP
PARI/GP
isPerfect(n)=sigma(n,-1)==2
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Pascal
Pascal
program PerfectNumbers;   function isPerfect(number: longint): boolean; var i, sum: longint;   begin sum := 1; for i := 2 to round(sqrt(real(number))) do if (number mod i = 0) then sum := sum + i + (number div i); isPerfect := (sum = number); end;   var candidate: longint;   begin writeln('Perfect numbers from 1 to 33550337:'); for candidate := 2 to 33550337 do if isPerfect(candidate) then writeln (candidate, ' is a perfect number.'); end.
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#m4
m4
divert(-1)   # 1-based indexing of a string's characters. define(`get',`substr(`$1',decr(`$2'),1)') define(`set',`substr(`$1',0,decr(`$2'))`'$3`'substr(`$1',`$2')') define(`swap', `pushdef(`_u',`get(`$1',`$2')')`'dnl pushdef(`_v',`get(`$1',`$3')')`'dnl set(set(`$1',`$2',_v),`$3',_u)`'dnl popdef(`_u',`_v')')   # $1-fold repetition of $2. define(`repeat',`ifelse($1,0,`',`$2`'$0(decr($1),`$2')')')   # # Heap's algorithm. Algorithm 2 in Robert Sedgewick, 1977. Permutation # generation methods. ACM Comput. Surv. 9, 2 (June 1977), 137-164. # # This implementation permutes the characters in a string of length no # more than 9. On longer strings, it may strain the resources of a # very old implementation of m4. # define(`permutations', `ifelse($2,`',`$1 $0(`$1',repeat(len(`$1'),1),2)', `ifelse(eval(($3) <= len(`$1')),1, `ifelse(eval(get($2,$3) < $3),1, `swap(`$1',_$0($2,$3),$3) $0(swap(`$1',_$0($2,$3),$3),set($2,$3,incr(get($2,$3))),2)', `$0(`$1',set($2,$3,1),incr($3))')')')') define(`_permutations',`eval((($2) % 2) + ((1 - (($2) % 2)) * get($1,$2)))')   divert`'dnl permutations(`123') permutations(`abcd')
http://rosettacode.org/wiki/Playing_cards
Playing cards
Task Create a data structure and the associated methods to define and manipulate a deck of   playing cards. The deck should contain 52 unique cards. The methods must include the ability to:   make a new deck   shuffle (randomize) the deck   deal from the deck   print the current contents of a deck Each card must have a pip value and a suit value which constitute the unique value of the card. Related tasks: Card shuffles Deal cards_for_FreeCell War Card_Game Poker hand_analyser Go Fish
#XPL0
XPL0
char Deck(52); \card structure (low 2 bits = suit) def Players = 4; \number of players to deal to char Hand(Players, 52); \each player's hand int Card, N, I, J, T; char Suit, Royal; [for Card:= 0 to 52-1 do \make a new deck Deck(Card):= Card; for N:= 0 to 10000 do \shuffle the deck [I:= Ran(52); J:= Ran(52); T:= Deck(I); Deck(I):= Deck(J); Deck(J):= T; ]; for N:= 0 to 52-1 do \deal from the deck [Card:= Deck(N); I:= N/Players; J:= rem(0); Hand(J, I):= Card; ]; Suit:= "HDCS "; \print each player's hand Royal:= "JQK "; \ (= contents of the deck) for J:= 0 to Players-1 do \e.g: 2D 3C 10C AS KD [for I:= 0 to 52/Players -1 do [Card:= Hand(J, I); N:= Card>>2 + 1; \pip value if N = 1 then ChOut(0, ^A) else if N >= 11 then ChOut(0, Royal(N-11)) else IntOut(0, N); ChOut(0, Suit(Card&3)); ChOut(0, ^ ); ]; CrLf(0); ]; ]
http://rosettacode.org/wiki/Pi
Pi
Create a program to continually calculate and output the next decimal digit of   π {\displaystyle \pi }   (pi). The program should continue forever (until it is aborted by the user) calculating and outputting each decimal digit in succession. The output should be a decimal sequence beginning   3.14159265 ... Note: this task is about   calculating   pi.   For information on built-in pi constants see Real constants and functions. Related Task Arithmetic-geometric mean/Calculate Pi
#Visual_Basic
Visual Basic
Option Explicit   Sub Main() Const VECSIZE As Long = 3350 Const BUFSIZE As Long = 201 Dim buffer(1 To BUFSIZE) As Long Dim vect(1 To VECSIZE) As Long Dim more As Long, karray As Long, num As Long, k As Long, l As Long, n As Long   For n = 1 To VECSIZE vect(n) = 2 Next n For n = 1 To BUFSIZE karray = 0 For l = VECSIZE To 1 Step -1 num = 100000 * vect(l) + karray * l karray = num \ (2 * l - 1) vect(l) = num - karray * (2 * l - 1) Next l k = karray \ 100000 buffer(n) = more + k more = karray - k * 100000 Next n Debug.Print CStr(buffer(1)); Debug.Print "." l = 0 For n = 2 To BUFSIZE Debug.Print Format$(buffer(n), "00000"); l = l + 1 If l = 10 Then l = 0 Debug.Print 'line feed End If Next n End Sub
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Perl
Perl
sub perf { my $n = shift; my $sum = 0; foreach my $i (1..$n-1) { if ($n % $i == 0) { $sum += $i; } } return $sum == $n; }
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#Maple
Maple
combinat:-permute(3); [[1, 2, 3], [1, 3, 2], [2, 1, 3], [2, 3, 1], [3, 1, 2], [3, 2, 1]]   combinat:-permute([a,b,c]); [[a, b, c], [a, c, b], [b, a, c], [b, c, a], [c, a, b], [c, b, a]]
http://rosettacode.org/wiki/Playing_cards
Playing cards
Task Create a data structure and the associated methods to define and manipulate a deck of   playing cards. The deck should contain 52 unique cards. The methods must include the ability to:   make a new deck   shuffle (randomize) the deck   deal from the deck   print the current contents of a deck Each card must have a pip value and a suit value which constitute the unique value of the card. Related tasks: Card shuffles Deal cards_for_FreeCell War Card_Game Poker hand_analyser Go Fish
#zkl
zkl
const Diamonds=1, Spades=3, Clubs=0, Hearts=2, Ace=1; // informational var suits=T(0x1F0D1,0x1F0C1,0x1F0B1,0x1F0A1); //unicode 🃑,🃁,🂱,🂡   class Card{ fcn init(pip,suit){ // or 0..51 reg p,s; if(vm.numArgs==1){ s=pip/13; p=pip%13; } else { p=pip; s=suit } var [const] _pip=p, _suit=s; } fcn toString{ p:=_pip + (_pip>=11); (suits[_suit]+p).toString(8); // int-->UTF-8 } }   class Deck{ //--> 52 shuffled Cards var [const] deck=L(); fcn init{ (0).pump(52,deck.clear().write,Card); shuffle(); } fcn shuffle{ deck.shuffle() } fcn deal(cards=5){ deck.pop(0,cards); } fcn toString{ deck.pump(String,"toString"); } }
http://rosettacode.org/wiki/Pi
Pi
Create a program to continually calculate and output the next decimal digit of   π {\displaystyle \pi }   (pi). The program should continue forever (until it is aborted by the user) calculating and outputting each decimal digit in succession. The output should be a decimal sequence beginning   3.14159265 ... Note: this task is about   calculating   pi.   For information on built-in pi constants see Real constants and functions. Related Task Arithmetic-geometric mean/Calculate Pi
#Visual_Basic_.NET
Visual Basic .NET
Imports System Imports System.Numerics   Public Module Module1 Public Sub Main() Dim two, three, four, seven, ten, k, q, t, l, n, r, nn, nr As BigInteger, first As Boolean = True two = New BigInteger(2) : three = New BigInteger(3) : four = two + two seven = three + four : ten = three + seven : k = BigInteger.One q = k : t = k : l = three : n = three : r = BigInteger.Zero While True If four * q + r - t < n * t Then Console.Write(n) : If first Then Console.Write(".") : first = False nr = ten * (r - n * t) : n = ten * (three * q + r) / t - ten * n q *= ten Else nr = (two * q + r) * l : nn = (q * seven * k + two + r * l) / (t * l) q *= k : t *= l : l += two : k += BigInteger.One : n = nn End If r = nr End While End Sub   End Module
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Phix
Phix
function is_perfect(integer n) return sum(factors(n,-1))=n end function for i=2 to 100000 do if is_perfect(i) then ?i end if end for
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#PHP
PHP
function is_perfect($number) { $sum = 0; for($i = 1; $i < $number; $i++) { if($number % $i == 0) $sum += $i; } return $sum == $number; }   echo "Perfect numbers from 1 to 33550337:" . PHP_EOL; for($num = 1; $num < 33550337; $num++) { if(is_perfect($num)) echo $num . PHP_EOL; }
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#Mathematica.2FWolfram_Language
Mathematica/Wolfram Language
  (***Standard list functions:*) fold[f_, x_, {}] := x fold[f_, x_, {h_, t___}] := fold[f, f[x, h], {t}] insert[L_, x_, n_] := Join[L[[;; n - 1]], {x}, L[[n ;;]]]   (***Generate all permutations of a list S:*)   permutations[S_] := fold[Join @@ (Function[{L}, Table[insert[L, #2, k + 1], {k, 0, Length[L]}]] /@ #1) &, {{}}, S]  
http://rosettacode.org/wiki/Playing_cards
Playing cards
Task Create a data structure and the associated methods to define and manipulate a deck of   playing cards. The deck should contain 52 unique cards. The methods must include the ability to:   make a new deck   shuffle (randomize) the deck   deal from the deck   print the current contents of a deck Each card must have a pip value and a suit value which constitute the unique value of the card. Related tasks: Card shuffles Deal cards_for_FreeCell War Card_Game Poker hand_analyser Go Fish
#ZX_Spectrum_Basic
ZX Spectrum Basic
10 GOSUB 5000 20 CLS 30 PRINT "Options:" 40 PRINT "1: Shuffle deck" 50 PRINT "2: Deal cards" 60 PRINT "3: Display deck" 70 INPUT o 80 IF o<1 OR o>3 OR o<>INT o THEN GOTO 70 90 GO SUB (o+1)*1000 100 GO TO 20   999 REM convert index to card 1000 LET s=INT ((x-1)/13)+1 1010 LET p=x-13*(s-1) 1020 LET n=s-2*INT (s/2)+1 1030 LET c$=p$(p)+CHR$ 16+CHR$ (n AND n>1)+s$(s): REM colour codes to force red or black 1040 RETURN   1999 REM shuffle - only a naive shuffle algorithm but it'll do; the modularity of the program means this is easy enough to modify 2000 CLS : PRINT FLASH 1;"Shuffling..." 2010 LET s=1: REM changing s allows shuffling the remainder of an undealt deck, say 2020 FOR x=1 TO 100 2030 LET a=INT (RND*53-s)+s 2040 LET b=INT (RND*53-s)+s 2050 LET n=d(a) 2060 LET d(a)=d(b) 2070 LET d(b)=n 2080 NEXT x 2090 RETURN   2999 REM deal 3000 INPUT "How many players? ";p 3010 INPUT "How many cards? ";c 3020 IF c<1 OR p<1 OR c<>INT c OR p<>INT p THEN PRINT "Don't be silly!": GO TO 3000 3030 IF c*p>52 THEN PRINT "Not enough cards for that!": GO TO 3000 3040 CLS : DIM h(p,c) 3050 LET k=1 3060 FOR f=1 TO c 3070 FOR e=1 TO p 3080 LET h(e,f)=d(k) 3090 LET k=k+1 3100 NEXT e 3110 NEXT f 3120 FOR e=1 TO p 3130 PRINT "Player ";e;"'s hand:" 3140 FOR f=1 TO c 3150 LET x=h(e,f) 3160 GO SUB 1000 3170 PRINT c$;" "; 3180 NEXT e 3190 PRINT 3200 NEXT f 3210 PRINT 3220 PRINT "Remaining deck:" 3230 IF c*p=52 THEN PRINT "none" 3240 GO SUB 4010 3250 RETURN   3999 REM display deck 4000 CLS : LET k=1 4010 FOR y=k TO 52: REM enter here with k>1 to show the rest of an undealt deck 4020 LET x=d(y) 4030 GO SUB 1000 4040 PRINT c$ 4050 NEXT y 4060 FOR y=0 TO 1000 4070 NEXT y 4080 RETURN   4999 REM initialise 5000 DIM d(52) 5010 GO SUB 6000 5020 LET s$=CHR$ 144+CHR$ 145+CHR$ 146+CHR$ 147: REM or LET s$="HSDC" if you don't want symbols 5030 LET p$="A23456789TJQK" 5040 FOR x=1 TO 52 5050 LET d(x)=x 5060 NEXT x 5070 RETURN   5999 REM characters - the ZX Spectrum character set doesn't contain suit symbols 6000 RESTORE 7000 6010 FOR x=65368 TO 65399 6020 READ a 6030 POKE x,a 6040 NEXT x 6050 RETURN   7000 DATA BIN 01101100: REM 108 7010 DATA BIN 11111110: REM 254 7020 DATA BIN 11111110: REM 254 7030 DATA BIN 11111110: REM 254 7040 DATA BIN 01111100: REM 124 7050 DATA BIN 00111000: REM 56 7060 DATA BIN 00010000: REM 16 7070 DATA BIN 00000000: REM 0   7080 DATA BIN 00010000: REM 16 7090 DATA BIN 00111000: REM 56 7100 DATA BIN 01111100: REM 124 7110 DATA BIN 11111110: REM 254 7120 DATA BIN 01010100: REM 84 7130 DATA BIN 00010000: REM 16 7140 DATA BIN 01111100: REM 124 7150 DATA BIN 00000000: REM 0   7160 DATA BIN 00010000: REM 16 7170 DATA BIN 00111000: REM 56 7180 DATA BIN 01111100: REM 124 7190 DATA BIN 11111110: REM 254 7200 DATA BIN 01111100: REM 124 7210 DATA BIN 00111000: REM 56 7220 DATA BIN 00010000: REM 16 7230 DATA BIN 00000000: REM 0   7240 DATA BIN 00010000: REM 16 7250 DATA BIN 00111000: REM 56 7260 DATA BIN 01010100: REM 84 7270 DATA BIN 11111110: REM 254 7280 DATA BIN 01010100: REM 84 7290 DATA BIN 00010000: REM 16 7300 DATA BIN 01111100: REM 124 7310 DATA BIN 00000000: REM 0
http://rosettacode.org/wiki/Pi
Pi
Create a program to continually calculate and output the next decimal digit of   π {\displaystyle \pi }   (pi). The program should continue forever (until it is aborted by the user) calculating and outputting each decimal digit in succession. The output should be a decimal sequence beginning   3.14159265 ... Note: this task is about   calculating   pi.   For information on built-in pi constants see Real constants and functions. Related Task Arithmetic-geometric mean/Calculate Pi
#Wren
Wren
import "/big" for BigInt import "io" for Stdout   var calcPi = Fn.new { var nn = BigInt.zero var nr = BigInt.zero var q = BigInt.one var r = BigInt.zero var t = BigInt.one var k = BigInt.one var n = BigInt.three var l = BigInt.three var first = true while (true) { if (q * BigInt.four + r - t < n * t) { System.write(n) if (first) { System.write(".") first = false } Stdout.flush() nr = (r - n * t) * BigInt.ten n = (q * BigInt.three + r) * BigInt.ten / t - n * BigInt.ten q = q * BigInt.ten r = nr } else { nr = (q * BigInt.two + r) * l nn = (q * BigInt.new(7) * k + BigInt.two + r * l) / (t * l) q = q * k t = t * l l = l + BigInt.two k = k + BigInt.one n = nn.copy() r = nr } } }   calcPi.call()
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Picat
Picat
go => println(perfect1=[I : I in 1..10_000, perfect1(I)]), nl.   perfect1(N) => sum(divisors(N)) == N. divisors(N) = [J: J in 1..1+N div 2, N mod J == 0].
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#PicoLisp
PicoLisp
(de perfect (N) (let C 0 (for I (/ N 2) (and (=0 (% N I)) (inc 'C I)) ) (= C N) ) )
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#MATLAB_.2F_Octave
MATLAB / Octave
perms([1,2,3,4])
http://rosettacode.org/wiki/Pi
Pi
Create a program to continually calculate and output the next decimal digit of   π {\displaystyle \pi }   (pi). The program should continue forever (until it is aborted by the user) calculating and outputting each decimal digit in succession. The output should be a decimal sequence beginning   3.14159265 ... Note: this task is about   calculating   pi.   For information on built-in pi constants see Real constants and functions. Related Task Arithmetic-geometric mean/Calculate Pi
#Yabasic
Yabasic
n = 1000 long = 10 * int(n / 4) needdecimal = 1 //true dim a(long) nines = 0 predigit = 0 // {First predigit is a 0}   for j = 1 to long a(j-1) = 2 // {Start with 2s} next j   for j = 1 to n q = 0 for i = long to 1 step -1 // {Work backwards} x = 10*a(i-1) + q*i a(i-1) = mod(x, (2*i - 1)) q = int(x / (2*i - 1)) next i a(0) = mod(q, 10) q = int(q / 10) if q = 9 then nines = nines + 1 else if q = 10 then d = predigit+1 gosub outputd if nines > 0 then for k = 1 to nines d = 0 gosub outputd next k end if predigit = 0 nines = 0 else d = predigit gosub outputd predigit = q if nines <> 0 then for k = 1 to nines d = 9 gosub outputd next k nines = 0 end if end if end if next j print predigit end   label outputd if needdecimal then if d = 0 then return : fi print d; print "."; needdecimal = 0 //false else print "", d; endif return
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#PL.2FI
PL/I
perfect: procedure (n) returns (bit(1)); declare n fixed; declare sum fixed; declare i fixed binary;   sum = 0; do i = 1 to n-1; if mod(n, i) = 0 then sum = sum + i; end; return (sum=n); end perfect;
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#PL.2FM
PL/M
100H: /* FIND SOME PERFECT NUMBERS: NUMBERS EQUAL TO THE SUM OF THEIR PROPER */ /* DIVISORS */ /* CP/M SYSTEM CALL AND I/O ROUTINES */ BDOS: PROCEDURE( FN, ARG ); /* CP/M BDOS SYSTEM CALL */ DECLARE FN BYTE, ARG ADDRESS; GOTO 5; END BDOS; PR$CHAR: PROCEDURE( C ); DECLARE C BYTE; CALL BDOS( 2, C ); END; PR$STRING: PROCEDURE( S ); DECLARE S ADDRESS; CALL BDOS( 9, S ); END; PR$NL: PROCEDURE; CALL PR$CHAR( 0DH ); CALL PR$CHAR( 0AH ); END; PR$NUMBER: PROCEDURE( N ); DECLARE N ADDRESS; DECLARE V ADDRESS, N$STR( 6 ) BYTE, W BYTE; V = N; W = LAST( N$STR ); N$STR( W ) = '$'; N$STR( W := W - 1 ) = '0' + ( V MOD 10 ); DO WHILE( ( V := V / 10 ) > 0 ); N$STR( W := W - 1 ) = '0' + ( V MOD 10 ); END; CALL PR$STRING( .N$STR( W ) ); END PR$NUMBER;   /* TASK */ /* RETURNS TRUE IF N IS PERFECT, 0 OTHERWISE */ IS$PERFECT: PROCEDURE( N )BYTE; DECLARE N ADDRESS; DECLARE ( F1, F2, SUM ) ADDRESS; SUM = 1; F1 = 2; F2 = N; DO WHILE( F1 * F1 <= N ); IF N MOD F1 = 0 THEN DO; SUM = SUM + F1; F2 = N / F1; /* AVOID COUNTING E.G., 2 TWICE AS A FACTOR OF 4 */ IF F2 > F1 THEN SUM = SUM + F2; END; F1 = F1 + 1; END; RETURN SUM = N; END IS$PERFECT ; /* TEST IS$PERFECT */ DECLARE N ADDRESS; DO N = 2 TO 10$000; IF IS$PERFECT( N ) THEN DO; CALL PR$CHAR( ' ' ); CALL PR$NUMBER( N ); END; END; EOF
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#Maxima
Maxima
next_permutation(v) := block([n, i, j, k, t], n: length(v), i: 0, for k: n - 1 thru 1 step -1 do (if v[k] < v[k + 1] then (i: k, return())), j: i + 1, k: n, while j < k do (t: v[j], v[j]: v[k], v[k]: t, j: j + 1, k: k - 1), if i = 0 then return(false), j: i + 1, while v[j] < v[i] do j: j + 1, t: v[j], v[j]: v[i], v[i]: t, true )$   print_perm(n) := block([v: makelist(i, i, 1, n)], disp(v), while next_permutation(v) do disp(v) )$   print_perm(3); /* [1, 2, 3] [1, 3, 2] [2, 1, 3] [2, 3, 1] [3, 1, 2] [3, 2, 1] */
http://rosettacode.org/wiki/Pi
Pi
Create a program to continually calculate and output the next decimal digit of   π {\displaystyle \pi }   (pi). The program should continue forever (until it is aborted by the user) calculating and outputting each decimal digit in succession. The output should be a decimal sequence beginning   3.14159265 ... Note: this task is about   calculating   pi.   For information on built-in pi constants see Real constants and functions. Related Task Arithmetic-geometric mean/Calculate Pi
#zkl
zkl
var [const] BN=Import("zklBigNum"), one=BN(1), two=BN(2), three=BN(3), four=BN(4), seven=BN(7), ten=BN(10);   fcn calcPiDigits{ reg q=BN(1), r=BN(0), t=BN(1), k=BN(1), n=BN(3), l=BN(3); first:=True; N:=0; while(True){ if((N+=1)==1000){ GarbageMan.collect(); N=0; } // take a deep breath ... if(four*q + r - t < n*t){ n.print(); if(first){ print("."); first=False; } nr:=(r - n*t).mul(ten); // 10 * (r - n * t); n=(three*q).add(r).mul(ten) // ((10*(3*q + r))/t) - 10*n; .div(t).sub(ten*n); q.mul(ten); // q *= 10; r=nr; }else{ nr:=(two*q).add(r).mul(l); // (2*q + r)*l; nn:=(q*seven).mul(k).add(two) // (q*(7*k + 2) + r*l)/(t*l); .add(r*l).div(t*l); q.mul(k); t.mul(l); // q*=k; t*=l; l.add(two); k.add(one); // l+=2; k++; n=nn; r=nr; } } }();
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#PowerShell
PowerShell
Function IsPerfect($n) { $sum=0 for($i=1;$i-lt$n;$i++) { if($n%$i -eq 0) { $sum += $i } } return $sum -eq $n }   Returns "True" if the given number is perfect and "False" if it's not.
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Prolog
Prolog
tt_divisors(X, N, TT) :- Q is X / N, ( 0 is X mod N -> (Q = N -> TT1 is N + TT; TT1 is N + Q + TT); TT = TT1), ( sqrt(X) > N + 1 -> N1 is N+1, tt_divisors(X, N1, TT1); TT1 = X).   perfect(X) :- tt_divisors(X, 2, 1).   perfect_numbers(N, L) :- numlist(2, N, LN), include(perfect, LN, L).
http://rosettacode.org/wiki/Pentagram
Pentagram
A pentagram is a star polygon, consisting of a central pentagon of which each side forms the base of an isosceles triangle. The vertex of each triangle, a point of the star, is 36 degrees. Task Draw (or print) a regular pentagram, in any orientation. Use a different color (or token) for stroke and fill, and background. For the fill it should be assumed that all points inside the triangles and the pentagon are inside the pentagram. See also Angle sum of a pentagram
#Action.21
Action!
INCLUDE "D2:REAL.ACT" ;from the Action! Tool Kit   DEFINE REALPTR="CARD" TYPE PointR=[REALPTR x,y]   INT ARRAY SinTab=[ 0 4 9 13 18 22 27 31 36 40 44 49 53 58 62 66 71 75 79 83 88 92 96 100 104 108 112 116 120 124 128 132 136 139 143 147 150 154 158 161 165 168 171 175 178 181 184 187 190 193 196 199 202 204 207 210 212 215 217 219 222 224 226 228 230 232 234 236 237 239 241 242 243 245 246 247 248 249 250 251 252 253 254 254 255 255 255 256 256 256 256]   INT FUNC Sin(INT a) WHILE a<0 DO a==+360 OD WHILE a>360 DO a==-360 OD IF a<=90 THEN RETURN (SinTab(a)) ELSEIF a<=180 THEN RETURN (SinTab(180-a)) ELSEIF a<=270 THEN RETURN (-SinTab(a-180)) ELSE RETURN (-SinTab(360-a)) FI RETURN (0)   INT FUNC Cos(INT a) RETURN (Sin(a-90))   PROC Det(REAL POINTER x1,y1,x2,y2,res) REAL tmp1,tmp2   RealMult(x1,y2,tmp1) RealMult(y1,x2,tmp2) RealSub(tmp1,tmp2,res) RETURN   BYTE FUNC IsZero(REAL POINTER a) CHAR ARRAY s(10)   StrR(a,s) IF s(0)=1 AND s(1)='0 THEN RETURN (1) FI RETURN (0)   BYTE FUNC Intersection(PointR POINTER p1,p2,p3,p4,res) REAL det1,det2,dx1,dx2,dy1,dy2,nom,denom   Det(p1.x,p1.y,p2.x,p2.y,det1) Det(p3.x,p3.y,p4.x,p4.y,det2) RealSub(p1.x,p2.x,dx1) RealSub(p1.y,p2.y,dy1) RealSub(p3.x,p4.x,dx2) RealSub(p3.y,p4.y,dy2) Det(dx1,dy1,dx2,dy2,denom)   IF IsZero(denom) THEN RETURN (0) FI   Det(det1,dx1,det2,dx2,nom) RealDiv(nom,denom,res.x) Det(det1,dy1,det2,dy2,nom) RealDiv(nom,denom,res.y) RETURN (1)   PROC FloodFill(BYTE x0,y0) BYTE ARRAY xs(300),ys(300) INT first,last   first=0 last=0 xs(first)=x0 ys(first)=y0   WHILE first<=last DO x0=xs(first) y0=ys(first) first==+1 IF Locate(x0,y0)=0 THEN Plot(x0,y0) IF Locate(x0-1,y0)=0 THEN last==+1 xs(last)=x0-1 ys(last)=y0 FI IF Locate(x0+1,y0)=0 THEN last==+1 xs(last)=x0+1 ys(last)=y0 FI IF Locate(x0,y0-1)=0 THEN last==+1 xs(last)=x0 ys(last)=y0-1 FI IF Locate(x0,y0+1)=0 THEN last==+1 xs(last)=x0 ys(last)=y0+1 FI FI OD RETURN   PROC Pentagram(INT x0,y0,r,a0 BYTE c1,c2) INT ARRAY xs(16),ys(16) INT angle BYTE i PointR p1,p2,p3,p4,p REAL p1x,p1y,p2x,p2y,p3x,p3y,p4x,p4y,px,py   p1.x=p1x p1.y=p1y p2.x=p2x p2.y=p2y p3.x=p3x p3.y=p3y p4.x=p4x p4.y=p4y p.x=px p.y=py    ;outer points angle=a0 FOR i=0 TO 4 DO xs(i)=r*Sin(angle)/256+x0 ys(i)=r*Cos(angle)/256+y0 angle==+144 OD    ;intersection points FOR i=0 TO 4 DO IntToReal(xs(i MOD 5),p1x) IntToReal(ys(i MOD 5),p1y) IntToReal(xs((1+i) MOD 5),p2x) IntToReal(ys((1+i) MOD 5),p2y) IntToReal(xs((2+i) MOD 5),p3x) IntToReal(ys((2+i) MOD 5),p3y) IntToReal(xs((3+i) MOD 5),p4x) IntToReal(ys((3+i) MOD 5),p4y) Intersection(p1,p2,p3,p4,p) xs(5+i)=RealToInt(px) ys(5+i)=RealToInt(py) OD    ;centers of triangles FOR i=0 TO 4 DO xs(10+i)=(xs(i)+xs(5+i)+xs(5+(i+2) MOD 5))/3 ys(10+i)=(ys(i)+ys(5+i)+ys(5+(i+2) MOD 5))/3 OD    ;center of pentagon xs(15)=0 ys(15)=0 FOR i=5 TO 9 DO xs(15)==+xs(i) ys(15)==+ys(i) OD xs(15)==/5 ys(15)==/5    ;draw lines COLOR=c1 FOR i=0 TO 5 DO IF i=0 THEN Plot(xs(i MOD 5),ys(i MOD 5)) ELSE DrawTo(xs(i MOD 5),ys(i MOD 5)) FI OD    ;fill COLOR=c2 FOR i=10 TO 15 DO FloodFill(xs(i),ys(i)) OD RETURN   PROC Main() BYTE CH=$02FC   Graphics(7+16) SetColor(0,8,4) SetColor(1,8,8) SetColor(2,8,12) Pentagram(40,48,40,0,1,2) Pentagram(119,48,40,15,2,3)   DO UNTIL CH#$FF OD CH=$FF RETURN
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#Mercury
Mercury
  :- module permutations2. :- interface.   :- import_module io.   :- pred main(io::di, io::uo) is det.     :- import_module list. :- import_module set_ordlist. :- import_module set. :- import_module solutions.   %% permutationSet(List, Set) is true if List is a permutation of Set: :- pred permutationSet(list(A)::out,set(A)::in) is nondet.   %% Two ways to compute all permutations of a given list (using backtracking): :- func all_permutations1(list(int))=set_ordlist.set_ordlist(list(int)). :- func all_permutations2(list(int))=set_ordlist.set_ordlist(list(int)).   :- implementation.     permutationSet([],set.init). permutationSet([H|T], S) :- set.member(H,S), permutationSet(T,set.delete(S,H)).   all_permutations1(L) = solutions_set(pred(X::out) is nondet:-permutationSet(X,set.from_list(L))).   %%Alternatively, using the imported list.perm predicate: all_permutations2(L) = solutions_set(pred(X::out) is nondet:-perm(L,X)).   main(!IO) :- print(all_permutations1([1,2,3,4]),!IO), nl(!IO), print(all_permutations2([1,2,3,4]),!IO).  
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#PureBasic
PureBasic
Procedure is_Perfect_number(n) Protected summa, i=1, result=#False Repeat If Not n%i summa+i EndIf i+1 Until i>=n If summa=n result=#True EndIf ProcedureReturn result EndProcedure
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Python
Python
def perf1(n): sum = 0 for i in range(1, n): if n % i == 0: sum += i return sum == n
http://rosettacode.org/wiki/Pentagram
Pentagram
A pentagram is a star polygon, consisting of a central pentagon of which each side forms the base of an isosceles triangle. The vertex of each triangle, a point of the star, is 36 degrees. Task Draw (or print) a regular pentagram, in any orientation. Use a different color (or token) for stroke and fill, and background. For the fill it should be assumed that all points inside the triangles and the pentagon are inside the pentagram. See also Angle sum of a pentagram
#Ada
Ada
with Ada.Numerics.Elementary_Functions;   with SDL.Video.Windows.Makers; with SDL.Video.Renderers.Makers; with SDL.Video.Rectangles; with SDL.Events.Events;   procedure Pentagram is   Width  : constant := 600; Height : constant := 600; Offset : constant := 300.0; Radius : constant := 250.0;   use SDL.Video.Rectangles; use SDL.C;   Window  : SDL.Video.Windows.Window; Renderer : SDL.Video.Renderers.Renderer; Event  : SDL.Events.Events.Events;   type Node_Id is mod 5; Nodes : array (Node_Id) of Point;   procedure Calculate is use Ada.Numerics.Elementary_Functions; begin for I in Nodes'Range loop Nodes (I) := (X => int (Offset + Radius * Sin (Float (I), Cycle => 5.0)), Y => int (Offset - Radius * Cos (Float (I), Cycle => 5.0))); end loop; end Calculate;   function Orient_2D (A, B, C : Point) return int is ((B.X - A.X) * (C.Y - A.Y) - (B.Y - A.Y) * (C.X - A.X));   procedure Fill is Count : Natural; begin for Y in int (Offset - Radius) .. int (Offset + Radius) loop for X in int (Offset - Radius) .. int (Offset + Radius) loop Count := 0; for Node in Nodes'Range loop Count := Count + (if Orient_2D (Nodes (Node), Nodes (Node + 2), (X, Y)) > 0 then 1 else 0); end loop; if Count in 4 .. 5 then Renderer.Draw (Point => (X, Y)); end if; end loop; end loop; end Fill;   procedure Draw_Outline is begin for Node in Nodes'Range loop Renderer.Draw (Line => (Nodes (Node), Nodes (Node + 2))); end loop; end Draw_Outline;   procedure Wait is use type SDL.Events.Event_Types; begin loop SDL.Events.Events.Wait (Event); exit when Event.Common.Event_Type = SDL.Events.Quit; end loop; end Wait;   begin if not SDL.Initialise (Flags => SDL.Enable_Screen) then return; end if;   SDL.Video.Windows.Makers.Create (Win => Window, Title => "Pentagram", Position => SDL.Natural_Coordinates'(X => 10, Y => 10), Size => SDL.Positive_Sizes'(Width, Height), Flags => 0); SDL.Video.Renderers.Makers.Create (Renderer, Window.Get_Surface); Renderer.Set_Draw_Colour ((0, 0, 0, 255)); Renderer.Fill (Rectangle => (0, 0, Width, Height));   Calculate; Renderer.Set_Draw_Colour ((50, 50, 150, 255)); Fill; Renderer.Set_Draw_Colour ((0, 220, 0, 255)); Draw_Outline; Window.Update_Surface;   Wait; Window.Finalize; SDL.Finalise; end Pentagram;
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#Microsoft_Small_Basic
Microsoft Small Basic
'Permutations - sb n=4 printem = "True" For i = 1 To n p[i] = i EndFor count = 0 Last = "False" While Last = "False" If printem Then For t = 1 To n TextWindow.Write(p[t]) EndFor TextWindow.WriteLine("") EndIf count = count + 1 Last = "True" i = n - 1 While i > 0 If p[i] < p[i + 1] Then Last = "False" Goto exitwhile EndIf i = i - 1 EndWhile exitwhile: j = i + 1 k = n While j < k t = p[j] p[j] = p[k] p[k] = t j = j + 1 k = k - 1 EndWhile j = n While p[j] > p[i] j = j - 1 EndWhile j = j + 1 t = p[i] p[i] = p[j] p[j] = t EndWhile TextWindow.WriteLine("Number of permutations: "+count)
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Quackery
Quackery
[ 0 swap witheach + ] is sum ( [ --> n )   [ factors -1 pluck dip sum = ] is perfect ( n --> n )   say "Perfect numbers less than 10000:" cr 10000 times [ i^ 1+ perfect if [ i^ 1+ echo cr ] ]  
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#R
R
is.perf <- function(n){ if (n==0|n==1) return(FALSE) s <- seq (1,n-1) x <- n %% s m <- data.frame(s,x) out <- with(m, s[x==0]) return(sum(out)==n) } # Usage - Warning High Memory Usage is.perf(28) sapply(c(6,28,496,8128,33550336),is.perf)
http://rosettacode.org/wiki/Pentagram
Pentagram
A pentagram is a star polygon, consisting of a central pentagon of which each side forms the base of an isosceles triangle. The vertex of each triangle, a point of the star, is 36 degrees. Task Draw (or print) a regular pentagram, in any orientation. Use a different color (or token) for stroke and fill, and background. For the fill it should be assumed that all points inside the triangles and the pentagon are inside the pentagram. See also Angle sum of a pentagram
#Applesoft_BASIC
Applesoft BASIC
100 XO = 140 110 YO = 96 120 S = 90 130 B = 7 140 F = 6 150 C = 4 200 POKE 230,64 210 HCOLOR= B 220 HPLOT 0,0 230 CALL 62454 240 A = 49232 250 I = PEEK (A + 7) + PEEK (A + 2) 260 I = PEEK (A + 5) + PEEK (A) 300 SX = S 310 SY = S 320 PI = 3.1415926535 330 E = PI * 4 340 S = PI / 1.25 350 X = SIN (0) 360 Y = COS (0) 370 HCOLOR= F 380 PX = XO + X * SX 390 PY = YO - Y * SY 400 FOR I = 0 TO E STEP S 410 X = SIN (I) 420 Y = COS (I) 430 FOR J = 0 TO SX 440 HPLOT PX,PY TO XO + X * J,YO - Y * J 450 NEXT J 460 PX = XO + X * SX 470 PY = YO - Y * SY 480 NEXT I 500 HCOLOR= C 510 PX = XO + X * SX 520 PY = YO - Y * SY 600 FOR I = S TO E STEP S 610 X = SIN (I) 620 Y = COS (I) 630 HPLOT PX,PY TO XO + X * SX,YO - Y * SY 640 HPLOT PX + 1,PY TO XO + X * SX + 1,YO - Y * SY 650 HPLOT PX,PY + 1 TO XO + X * SX,YO - Y * SY + 1 660 HPLOT PX + 1,PY + 1 TO XO + X * SX + 1,YO - Y * SY + 1 670 PX = XO + X * SX 680 PY = YO - Y * SY 690 NEXT I
http://rosettacode.org/wiki/Pentagram
Pentagram
A pentagram is a star polygon, consisting of a central pentagon of which each side forms the base of an isosceles triangle. The vertex of each triangle, a point of the star, is 36 degrees. Task Draw (or print) a regular pentagram, in any orientation. Use a different color (or token) for stroke and fill, and background. For the fill it should be assumed that all points inside the triangles and the pentagon are inside the pentagram. See also Angle sum of a pentagram
#AutoHotkey
AutoHotkey
  #Include Gdip.ahk ; https://autohotkey.com/boards/viewtopic.php?f=6&t=6517 Width :=A_ScreenWidth, Height := A_ScreenHeight Gui, 1: +E0x20 +Caption +E0x80000 +LastFound +AlwaysOnTop +ToolWindow +OwnDialogs Gui, 1: Show, NA hwnd1 := WinExist() OnExit, Exit   If !pToken := Gdip_Startup() { MsgBox, 48, gdiplus error!, Gdiplus failed to start. . Please ensure you have gdiplus on your system ExitApp }   hbm := CreateDIBSection(Width, Height) hdc := CreateCompatibleDC() obm := SelectObject(hdc, hbm) G := Gdip_GraphicsFromHDC(hdc) Gdip_SetSmoothingMode(G, 4) pBrush := Gdip_BrushCreateSolid(0xFF6495ED) pPen := Gdip_CreatePen(0xff000000, 3)   ;--------------------------------- LL := 165 Cx := Floor(A_ScreenWidth/2) Cy := Floor(A_ScreenHeight/2) phi := 54 ;--------------------------------- loop, 5 { theta := abs(180-144-phi) p1x := Floor(Cx + LL * Cos(phi * 0.01745329252)) p1y := Floor(Cy + LL * Sin(phi * 0.01745329252)) p2x := Floor(Cx - LL * Cos(theta * 0.01745329252)) p2y := Floor(Cy - LL * Sin(theta * 0.01745329252)) phi+= 72 Gdip_FillPolygon(G, pBrush, p1x "," p1y "|" Cx "," Cy "|" p2x "," p2y) } loop, 5 { theta := abs(180-144-phi) p1x := Floor(Cx + LL * Cos(phi * 0.01745329252)) p1y := Floor(Cy + LL * Sin(phi * 0.01745329252)) p2x := Floor(Cx - LL * Cos(theta * 0.01745329252)) p2y := Floor(Cy - LL * Sin(theta * 0.01745329252)) phi+= 72 Gdip_DrawLines(G, pPen, p1x "," p1y "|" p2x "," p2y ) ; "|" Cx "," Cy ) } UpdateLayeredWindow(hwnd1, hdc, 0, 0, Width, Height) Gdip_DeleteBrush(pBrush) SelectObject(hdc, obm) DeleteObject(hbm) DeleteDC(hdc) Gdip_DeleteGraphics(G) return ;---------------------------------------------------------------------- Esc:: Exit: Gdip_Shutdown(pToken) ExitApp Return
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#Modula-2
Modula-2
MODULE Permute;   FROM Terminal IMPORT Read, Write, WriteLn;   FROM Terminal2 IMPORT WriteString;   CONST MAXIDX = 6; MINIDX = 1;   TYPE TInpCh = ['a'..'z']; TChr = SET OF TInpCh;   VAR n, nl: INTEGER; ch: CHAR; a: ARRAY[MINIDX..MAXIDX] OF CHAR; kt: TChr = TChr{'a'..'f'};   PROCEDURE output; VAR i: INTEGER; BEGIN FOR i := MINIDX TO n DO Write(a[i]) END; WriteString(" | "); END output;   PROCEDURE exchange(VAR x, y : CHAR); VAR z: CHAR; BEGIN z := x; x := y; y := z END exchange;   PROCEDURE permute(k: INTEGER); VAR i: INTEGER; BEGIN IF k = 1 THEN output; INC(nl); IF (nl MOD 8 = 1) THEN WriteLn END; ELSE permute(k-1); FOR i := MINIDX TO k-1 DO exchange(a[i], a[k]); permute(k-1); exchange(a[i], a[k]); END END END permute;   BEGIN n := 0; nl := 1; WriteString("Input {a,b,c,d,e,f} >"); REPEAT Read(ch); IF ch IN kt THEN INC(n); a[n] := ch; Write(ch) END UNTIL (ch <= " ") OR (n > MAXIDX);   WriteLn; IF n > 0 THEN permute(n) END; (*Wait*) END Permute.
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Racket
Racket
#lang racket (require math)   (define (perfect? n) (= (* n 2) (sum (divisors n))))   ; filtering to only even numbers for better performance (filter perfect? (filter even? (range 1e5))) ;-> '(0 6 28 496 8128)
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Raku
Raku
sub is-perf($n) { $n == [+] grep $n %% *, 1 .. $n div 2 }   # used as put ((1..Inf).hyper.grep: {.&is-perf})[^4];
http://rosettacode.org/wiki/Pentagram
Pentagram
A pentagram is a star polygon, consisting of a central pentagon of which each side forms the base of an isosceles triangle. The vertex of each triangle, a point of the star, is 36 degrees. Task Draw (or print) a regular pentagram, in any orientation. Use a different color (or token) for stroke and fill, and background. For the fill it should be assumed that all points inside the triangles and the pentagon are inside the pentagram. See also Angle sum of a pentagram
#C
C
#include<graphics.h> #include<stdio.h> #include<math.h>   #define pi M_PI   int main(){   char colourNames[][14] = { "BLACK", "BLUE", "GREEN", "CYAN", "RED", "MAGENTA", "BROWN", "LIGHTGRAY", "DARKGRAY", "LIGHTBLUE", "LIGHTGREEN", "LIGHTCYAN", "LIGHTRED", "LIGHTMAGENTA", "YELLOW", "WHITE" };   int stroke=0,fill=0,back=0,i;   double centerX = 300,centerY = 300,coreSide,armLength,pentaLength;   printf("Enter core pentagon side length : "); scanf("%lf",&coreSide);   printf("Enter pentagram arm length : "); scanf("%lf",&armLength);   printf("Available colours are :\n");   for(i=0;i<16;i++){ printf("%d. %s\t",i+1,colourNames[i]); if((i+1) % 3 == 0){ printf("\n"); } }   while(stroke==fill && fill==back){ printf("\nEnter three diffrenet options for stroke, fill and background : "); scanf("%d%d%d",&stroke,&fill,&back); }   pentaLength = coreSide/(2 * tan(pi/5)) + sqrt(armLength*armLength - coreSide*coreSide/4);   initwindow(2*centerX,2*centerY,"Pentagram");   setcolor(stroke-1);   setfillstyle(SOLID_FILL,back-1);   bar(0,0,2*centerX,2*centerY);   floodfill(centerX,centerY,back-1);   setfillstyle(SOLID_FILL,fill-1);   for(i=0;i<5;i++){ line(centerX + coreSide*cos(i*2*pi/5)/(2*sin(pi/5)),centerY + coreSide*sin(i*2*pi/5)/(2*sin(pi/5)),centerX + coreSide*cos((i+1)*2*pi/5)/(2*sin(pi/5)),centerY + coreSide*sin((i+1)*2*pi/5)/(2*sin(pi/5))); line(centerX + coreSide*cos(i*2*pi/5)/(2*sin(pi/5)),centerY + coreSide*sin(i*2*pi/5)/(2*sin(pi/5)),centerX + pentaLength*cos(i*2*pi/5 + pi/5),centerY + pentaLength*sin(i*2*pi/5 + pi/5)); line(centerX + coreSide*cos((i+1)*2*pi/5)/(2*sin(pi/5)),centerY + coreSide*sin((i+1)*2*pi/5)/(2*sin(pi/5)),centerX + pentaLength*cos(i*2*pi/5 + pi/5),centerY + pentaLength*sin(i*2*pi/5 + pi/5));   floodfill(centerX + coreSide*cos(i*2*pi/5 + pi/10)/(2*sin(pi/5)),centerY + coreSide*sin(i*2*pi/5 + pi/10)/(2*sin(pi/5)),stroke-1); }   floodfill(centerX,centerY,stroke-1);   getch();   closegraph(); }  
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#Modula-3
Modula-3
MODULE Permutations EXPORTS Main;   IMPORT IO, IntSeq;   CONST n = 3;   TYPE Domain = SET OF [ 1.. n ];   VAR   chosen: IntSeq.T; values := Domain { };   PROCEDURE GeneratePermutations(VAR chosen: IntSeq.T; remaining: Domain) = (* Recursively generates all the permutations of elements in the union of "chosen" and "values". Values in "chosen" have already been chosen; values in "remaining" can still be chosen. If "remaining" is empty, it prints the sequence and returns. Otherwise, it picks each element in "remaining", removes it, adds it to "chosen", recursively calls itself, then removes the last element of "chosen" and adds it back to "remaining". *) BEGIN FOR i := 1 TO n DO (* check if each element is in "remaining" *) IF i IN remaining THEN (* if so, remove from "remaining" and add to "chosen" *) remaining := remaining - Domain { i }; chosen.addhi(i); IF remaining # Domain { } THEN (* still something to process? do it *) GeneratePermutations(chosen, remaining); ELSE (* otherwise, print what we've chosen *) FOR j := 0 TO chosen.size() - 2 DO IO.PutInt(chosen.get(j)); IO.Put(", "); END; IO.PutInt(chosen.gethi()); IO.PutChar('\n'); END; (* add "i" back to "remaining" and remove from "chosen" *) remaining := remaining + Domain { i }; EVAL chosen.remhi(); END; END; END GeneratePermutations;   BEGIN   (* initial setup *) chosen := NEW(IntSeq.T).init(n); FOR i := 1 TO n DO values := values + Domain { i }; END;   GeneratePermutations(chosen, values);   END Permutations.
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#REBOL
REBOL
perfect?: func [n [integer!] /local sum] [ sum: 0 repeat i (n - 1) [ if zero? remainder n i [ sum: sum + i ] ] sum = n ]
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#REXX
REXX
/*REXX version of the ooRexx program (the code was modified to run with Classic REXX).*/ do i=1 to 10000 /*statement changed: LOOP ──► DO*/ if perfectNumber(i) then say i "is a perfect number" end exit   perfectNumber: procedure; parse arg n /*statements changed: ROUTINE,USE*/ sum=0 do i=1 to n%2 /*statement changed: LOOP ──► DO*/ if n//i==0 then sum=sum+i /*statement changed: sum += i */ end return sum=n
http://rosettacode.org/wiki/Pentagram
Pentagram
A pentagram is a star polygon, consisting of a central pentagon of which each side forms the base of an isosceles triangle. The vertex of each triangle, a point of the star, is 36 degrees. Task Draw (or print) a regular pentagram, in any orientation. Use a different color (or token) for stroke and fill, and background. For the fill it should be assumed that all points inside the triangles and the pentagon are inside the pentagram. See also Angle sum of a pentagram
#Delphi
Delphi
  unit Main;   interface   uses Winapi.Windows, Vcl.Graphics, Vcl.Forms, System.Math;   type TForm1 = class(TForm) procedure FormCreate(Sender: TObject); procedure FormPaint(Sender: TObject); private procedure DrawPentagram(len, x, y: Integer; fill, stoke: TColor); { Private declarations } public { Public declarations } end;   var Form1: TForm1; degrees144: double; degrees72: double; degrees18: double;   implementation   {$R *.dfm}   procedure TForm1.FormCreate(Sender: TObject); begin ClientHeight := 640; ClientWidth := 640; degrees144 := DegToRad(144); degrees72 := DegToRad(72); degrees18 := DegToRad(18); end;   procedure CreatePolygon(len, x, y, n: integer; ang: double; var points: TArray<TPoint>); var angle: Double; index, i, x2, y2: Integer; begin angle := 0; index := 0; SetLength(points, n + 1); points[index].Create(x, y);   for i := 1 to n do begin x2 := x + round(len * cos(angle)); y2 := y + round(len * sin(-angle)); x := x2; y := y2; angle := angle - ang;   points[index].Create(x2, y2); inc(index); end; points[index].Create(points[0]); end;   procedure TForm1.DrawPentagram(len, x, y: Integer; fill, stoke: TColor); var points, points_internal: TArray<TPoint>; L, H: Integer; begin // Calc of sides for draw internal pollygon // 2H+L = len -> 2H = len - L // L = 2H*sin(36/2) (Pythagorean theorem) // L = (len-L)sin(18) // L = len*sin(18)/[1+sin(18)]   L := round(len * sin(degrees18) / (1 + sin(degrees18)));   // H = (len - L)/2   H := (len - L) div 2;   CreatePolygon(L, x + H, y, 5, degrees72, points_internal); CreatePolygon(len, x, y, 5, degrees144, points);   with Canvas, Canvas.Brush do begin with pen do begin Color := stoke; Style := psSolid; Width := 5; end; Color := fill; Polygon(points_internal); Polygon(points); end; end;   procedure TForm1.FormPaint(Sender: TObject); begin with Canvas, Brush do begin Style := bsSolid; Color := clWhite; // fill background with white FillRect(ClientRect); end; drawPentagram(500, 70, 250, $ED9564, clDkGray); end;   end.
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#NetRexx
NetRexx
/* NetRexx */ options replace format comments java crossref symbols nobinary   import java.util.List import java.util.ArrayList   -- ============================================================================= /** * Permutation Iterator * <br /> * <br /> * Algorithm by E. W. Dijkstra, "A Discipline of Programming", Prentice-Hall, 1976, p.71 */ class RPermutationIterator implements Iterator   -- --------------------------------------------------------------------------- properties indirect perms = List permOrders = int[] maxN currentN first = boolean   -- --------------------------------------------------------------------------- properties constant isTrue = boolean (1 == 1) isFalse = boolean (1 \= 1)   -- --------------------------------------------------------------------------- method RPermutationIterator(initial = List) public setUp(initial) return   -- --------------------------------------------------------------------------- method RPermutationIterator(initial = Object[]) public init = ArrayList(initial.length) loop elmt over initial init.add(elmt) end elmt setUp(init) return   -- --------------------------------------------------------------------------- method RPermutationIterator(initial = Rexx[]) public init = ArrayList(initial.length) loop elmt over initial init.add(elmt) end elmt setUp(init) return   -- --------------------------------------------------------------------------- method setUp(initial = List) private setFirst(isTrue) setPerms(initial) setPermOrders(int[getPerms().size()]) setMaxN(getPermOrders().length) setCurrentN(0) po = getPermOrders() loop i_ = 0 while i_ < po.length po[i_] = i_ end i_ return   -- --------------------------------------------------------------------------- method hasNext() public returns boolean status = isTrue if getCurrentN() == factorial(getMaxN()) then status = isFalse setCurrentN(getCurrentN() + 1) return status   -- --------------------------------------------------------------------------- method next() public returns Object if isFirst() then setFirst(isFalse) else do po = getPermOrders() i_ = getMaxN() - 1 loop while po[i_ - 1] >= po[i_] i_ = i_ - 1 end   j_ = getMaxN() loop while po[j_ - 1] <= po[i_ - 1] j_ = j_ - 1 end   swap(i_ - 1, j_ - 1)   i_ = i_ + 1 j_ = getMaxN() loop while i_ < j_ swap(i_ - 1, j_ - 1) i_ = i_ + 1 j_ = j_ - 1 end end return reorder()   -- --------------------------------------------------------------------------- method remove() public signals UnsupportedOperationException signal UnsupportedOperationException()   -- --------------------------------------------------------------------------- method swap(i_, j_) private po = getPermOrders() save = po[i_] po[i_] = po[j_] po[j_] = save return   -- --------------------------------------------------------------------------- method reorder() private returns List result = ArrayList(getPerms().size()) loop ix over getPermOrders() result.add(getPerms().get(ix)) end ix return result   -- --------------------------------------------------------------------------- /** * Calculate n factorial: {@code n! = 1 * 2 * 3 .. * n} * @param n * @return n! */ method factorial(n) public static fact = 1 if n > 1 then loop i = 1 while i <= n fact = fact * i end i return fact   -- --------------------------------------------------------------------------- method main(args = String[]) public static thing02 = RPermutationIterator(['alpha', 'omega']) thing03 = RPermutationIterator([String 'one', 'two', 'three']) thing04 = RPermutationIterator(Arrays.asList([Integer(1), Integer(2), Integer(3), Integer(4)])) things = [thing02, thing03, thing04] loop thing over things N = thing.getMaxN() say 'Permutations:' N'! =' factorial(N) loop lineCount = 1 while thing.hasNext() prm = thing.next() say lineCount.right(8)':' prm.toString() end lineCount say 'Permutations:' N'! =' factorial(N) say end thing return  
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Ring
Ring
  for i = 1 to 10000 if perfect(i) see i + nl ok next   func perfect n sum = 0 for i = 1 to n - 1 if n % i = 0 sum = sum + i ok next if sum = n return 1 else return 0 ok return sum  
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Ruby
Ruby
def perf(n) sum = 0 for i in 1...n sum += i if n % i == 0 end sum == n end
http://rosettacode.org/wiki/Pentagram
Pentagram
A pentagram is a star polygon, consisting of a central pentagon of which each side forms the base of an isosceles triangle. The vertex of each triangle, a point of the star, is 36 degrees. Task Draw (or print) a regular pentagram, in any orientation. Use a different color (or token) for stroke and fill, and background. For the fill it should be assumed that all points inside the triangles and the pentagon are inside the pentagram. See also Angle sum of a pentagram
#EasyLang
EasyLang
xp = 10 yp = 40 linewidth 2 move xp yp while angle > -720 x = xp + cos angle * 80 y = yp + sin -angle * 80 line x y f[] &= x f[] &= y xp = x yp = y angle -= 144 . color 900 polygon f[]
http://rosettacode.org/wiki/Pentagram
Pentagram
A pentagram is a star polygon, consisting of a central pentagon of which each side forms the base of an isosceles triangle. The vertex of each triangle, a point of the star, is 36 degrees. Task Draw (or print) a regular pentagram, in any orientation. Use a different color (or token) for stroke and fill, and background. For the fill it should be assumed that all points inside the triangles and the pentagon are inside the pentagram. See also Angle sum of a pentagram
#Go
Go
package main   import ( "github.com/fogleman/gg" "math" )   func Pentagram(x, y, r float64) []gg.Point { points := make([]gg.Point, 5) for i := 0; i < 5; i++ { fi := float64(i) angle := 2*math.Pi*fi/5 - math.Pi/2 points[i] = gg.Point{x + r*math.Cos(angle), y + r*math.Sin(angle)} } return points }   func main() { points := Pentagram(320, 320, 250) dc := gg.NewContext(640, 640) dc.SetRGB(1, 1, 1) // White dc.Clear() for i := 0; i <= 5; i++ { index := (i * 2) % 5 p := points[index] dc.LineTo(p.X, p.Y) } dc.SetHexColor("#6495ED") // Cornflower Blue dc.SetFillRule(gg.FillRuleWinding) dc.FillPreserve() dc.SetRGB(0, 0, 0) // Black dc.SetLineWidth(5) dc.Stroke() dc.SavePNG("pentagram.png") }
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#Nim
Nim
import algorithm var v = [1, 2, 3] # List has to start sorted echo v while v.nextPermutation(): echo v
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Run_BASIC
Run BASIC
for i = 1 to 10000 if perf(i) then print i;" "; next i   FUNCTION perf(n) for i = 1 TO n - 1 IF n MOD i = 0 THEN sum = sum + i next i IF sum = n THEN perf = 1 END FUNCTION
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Rust
Rust
  fn main ( ) { fn factor_sum(n: i32) -> i32 { let mut v = Vec::new(); //create new empty array for x in 1..n-1 { //test vaules 1 to n-1 if n%x == 0 { //if current x is a factor of n v.push(x); //add x to the array } } let mut sum = v.iter().sum(); //iterate over array and sum it up return sum; }   fn perfect_nums(n: i32) { for x in 2..n { //test numbers from 1-n if factor_sum(x) == x {//call factor_sum on each value of x, if return value is = x println!("{} is a perfect number.", x); //print value of x } } } perfect_nums(10000); }  
http://rosettacode.org/wiki/Pell%27s_equation
Pell's equation
Pell's equation   (also called the Pell–Fermat equation)   is a   Diophantine equation   of the form: x2   -   ny2   =   1 with integer solutions for   x   and   y,   where   n   is a given non-square positive integer. Task requirements   find the smallest solution in positive integers to Pell's equation for   n = {61, 109, 181, 277}. See also   Wikipedia entry: Pell's equation.
#11l
11l
F solvePell(n) V x = Int(sqrt(n)) V (y, z, r) = (x, 1, x << 1) BigInt e1 = 1 BigInt e2 = 0 BigInt f1 = 0 BigInt f2 = 1 L y = r * z - y z = (n - y * y) I/ z r = (x + y) I/ z   (e1, e2) = (e2, e1 + e2 * r) (f1, f2) = (f2, f1 + f2 * r)   V (a, b) = (f2 * x + e2, f2) I a * a - n * b * b == 1 R (a, b)   L(n) [61, 109, 181, 277] V (x, y) = solvePell(n) print(‘x^2 - #3 * y^2 = 1 for x = #27 and y = #25’.format(n, x, y))
http://rosettacode.org/wiki/Pentagram
Pentagram
A pentagram is a star polygon, consisting of a central pentagon of which each side forms the base of an isosceles triangle. The vertex of each triangle, a point of the star, is 36 degrees. Task Draw (or print) a regular pentagram, in any orientation. Use a different color (or token) for stroke and fill, and background. For the fill it should be assumed that all points inside the triangles and the pentagon are inside the pentagram. See also Angle sum of a pentagram
#Haskell
Haskell
pentagram -w 400 -o pentagram_hs.svg
http://rosettacode.org/wiki/Pentagram
Pentagram
A pentagram is a star polygon, consisting of a central pentagon of which each side forms the base of an isosceles triangle. The vertex of each triangle, a point of the star, is 36 degrees. Task Draw (or print) a regular pentagram, in any orientation. Use a different color (or token) for stroke and fill, and background. For the fill it should be assumed that all points inside the triangles and the pentagon are inside the pentagram. See also Angle sum of a pentagram
#IS-BASIC
IS-BASIC
100 PROGRAM "Pentagra.bas" 110 OPTION ANGLE DEGREES 120 GRAPHICS HIRES 4 130 SET PALETTE BLUE,CYAN,YELLOW,BLACK 140 PLOT 640,700,ANGLE 288; 150 FOR I=1 TO 5 160 PLOT FORWARD 700,RIGHT 144; 170 NEXT 180 SET INK 3 190 SET BEAM OFF:PLOT 0,0,PAINT
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#OCaml
OCaml
(* Iterative, though loops are implemented as auxiliary recursive functions. Translation of Ada version. *) let next_perm p = let n = Array.length p in let i = let rec aux i = if (i < 0) || (p.(i) < p.(i+1)) then i else aux (i - 1) in aux (n - 2) in let rec aux j k = if j < k then let t = p.(j) in p.(j) <- p.(k); p.(k) <- t; aux (j + 1) (k - 1) else () in aux (i + 1) (n - 1); if i < 0 then false else let j = let rec aux j = if p.(j) > p.(i) then j else aux (j + 1) in aux (i + 1) in let t = p.(i) in p.(i) <- p.(j); p.(j) <- t; true;;   let print_perm p = let n = Array.length p in for i = 0 to n - 2 do print_int p.(i); print_string " " done; print_int p.(n - 1); print_newline ();;   let print_all_perm n = let p = Array.init n (function i -> i + 1) in print_perm p; while next_perm p do print_perm p done;;   print_all_perm 3;; (* 1 2 3 1 3 2 2 1 3 2 3 1 3 1 2 3 2 1 *)
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#SASL
SASL
  || The function which takes a number and returns a list of its factors (including one but excluding itself) || can be written factors n = { a <- 1.. n/2; n rem a = 0 } || If we define a perfect number as one which is equal to the sum of its factors (for example 6 = 3 + 2 + 1 is perfect) || we can write the list of all perfect numbers as perfects = { n <- 1... ; n = sum(factors n) }  
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#S-BASIC
S-BASIC
  $lines   rem - return p mod q function mod(p, q = integer) = integer end = p - q * (p/q)   rem - return true if n is perfect, otherwise false function isperfect(n = integer) = integer var sum, f1, f2 = integer sum = 1 f1 = 2 while (f1 * f1) <= n do begin if mod(n, f1) = 0 then begin sum = sum + f1 f2 = n / f1 if f2 > f1 then sum = sum + f2 end f1 = f1 + 1 end end = (sum = n)   rem - exercise the function   var k, found = integer   print "Searching up to"; search_limit; " for perfect numbers ..." found = 0 for k = 2 to search_limit if isperfect(k) then begin print k found = found + 1 end next k print found; " were found"   end  
http://rosettacode.org/wiki/Pell%27s_equation
Pell's equation
Pell's equation   (also called the Pell–Fermat equation)   is a   Diophantine equation   of the form: x2   -   ny2   =   1 with integer solutions for   x   and   y,   where   n   is a given non-square positive integer. Task requirements   find the smallest solution in positive integers to Pell's equation for   n = {61, 109, 181, 277}. See also   Wikipedia entry: Pell's equation.
#Ada
Ada
with Ada.Text_Io; with Ada.Numerics.Elementary_Functions; with Ada.Numerics.Big_Numbers.Big_Integers;   procedure Pells_Equation is use Ada.Numerics.Big_Numbers.Big_Integers;   type Pair is record V1, V2 : Big_Integer; end record;   procedure Solve_Pell (N : Natural; X, Y : out Big_Integer) is use Ada.Numerics.Elementary_Functions; Big_N : constant Big_Integer := To_Big_Integer (N); XX  : constant Big_Integer := To_Big_Integer (Natural (Float'Floor (Sqrt (Float (N))))); begin if XX**2 = Big_N then X := 1; Y := 0; return; end if;   declare YY  : Big_Integer := XX; Z  : Big_Integer := 1; R  : Big_Integer := 2 * XX; E  : Pair  := Pair'(V1 => 1, V2 => 0); F  : Pair  := Pair'(V1 => 0, V2 => 1); begin loop YY := R * Z - YY; Z  := (Big_N - YY**2) / Z; R  := (XX + YY) / Z; E  := Pair'(V1 => E.V2, V2 => R * E.V2 + E.V1); F  := Pair'(V1 => F.V2, V2 => R * F.V2 + F.V1); X  := E.V2 + XX * F.V2; Y  := F.V2; exit when X**2 - Big_N * Y**2 = 1; end loop; end; end Solve_Pell;   procedure Test (N : Natural) is   package Natural_Io is new Ada.Text_Io.Integer_Io (Natural); use Ada.Text_Io, Natural_Io;   X, Y : Big_Integer; begin Solve_Pell (N, X => X, Y => Y); Put ("X**2 - "); Put (N, Width => 3); Put (" * Y**2 = 1 for X = "); Put (To_String (X, Width => 22)); Put (" and Y = "); Put (To_String (Y, Width => 20)); New_Line; end Test;   begin Test (61); Test (109); Test (181); Test (277); end Pells_Equation;
http://rosettacode.org/wiki/Pentagram
Pentagram
A pentagram is a star polygon, consisting of a central pentagon of which each side forms the base of an isosceles triangle. The vertex of each triangle, a point of the star, is 36 degrees. Task Draw (or print) a regular pentagram, in any orientation. Use a different color (or token) for stroke and fill, and background. For the fill it should be assumed that all points inside the triangles and the pentagon are inside the pentagram. See also Angle sum of a pentagram
#J
J
require'plot' plot j./2 1 o./180p_1 %~ 144*i. 6
http://rosettacode.org/wiki/Pentagram
Pentagram
A pentagram is a star polygon, consisting of a central pentagon of which each side forms the base of an isosceles triangle. The vertex of each triangle, a point of the star, is 36 degrees. Task Draw (or print) a regular pentagram, in any orientation. Use a different color (or token) for stroke and fill, and background. For the fill it should be assumed that all points inside the triangles and the pentagon are inside the pentagram. See also Angle sum of a pentagram
#Java
Java
import java.awt.*; import java.awt.geom.Path2D; import javax.swing.*;   public class Pentagram extends JPanel {   final double degrees144 = Math.toRadians(144);   public Pentagram() { setPreferredSize(new Dimension(640, 640)); setBackground(Color.white); }   private void drawPentagram(Graphics2D g, int len, int x, int y, Color fill, Color stroke) { double angle = 0;   Path2D p = new Path2D.Float(); p.moveTo(x, y);   for (int i = 0; i < 5; i++) { int x2 = x + (int) (Math.cos(angle) * len); int y2 = y + (int) (Math.sin(-angle) * len); p.lineTo(x2, y2); x = x2; y = y2; angle -= degrees144; } p.closePath();   g.setColor(fill); g.fill(p);   g.setColor(stroke); g.draw(p); }   @Override public void paintComponent(Graphics gg) { super.paintComponent(gg); Graphics2D g = (Graphics2D) gg;   g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);   g.setStroke(new BasicStroke(5, BasicStroke.CAP_ROUND, 0));   drawPentagram(g, 500, 70, 250, new Color(0x6495ED), Color.darkGray); }   public static void main(String[] args) { SwingUtilities.invokeLater(() -> { JFrame f = new JFrame(); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.setTitle("Pentagram"); f.setResizable(false); f.add(new Pentagram(), BorderLayout.CENTER); f.pack(); f.setLocationRelativeTo(null); f.setVisible(true); }); } }
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#ooRexx
ooRexx
  /* REXX Compute bunch permutations of things elements */ Parse Arg bunch things If bunch='?' Then Call help If bunch=='' Then bunch=3 If datatype(bunch)<>'NUM' Then Call help 'bunch ('bunch') must be numeric' thing.='' Select When things='' Then things=bunch When datatype(things)='NUM' Then Nop Otherwise Do data=things things=words(things) Do i=1 To things Parse Var data thing.i data End End End If things<bunch Then Call help 'things ('things') must be >= bunch ('bunch')'   perms =0 Call time 'R' Call permSets things, bunch Say perms 'Permutations' Say time('E') 'seconds' Exit   /*--------------------------------------------------------------------------------------*/ first_word: return word(Arg(1),1) /*--------------------------------------------------------------------------------------*/ permSets: Procedure Expose perms thing. Parse Arg things,bunch aa.='' sep='' perm_elements='123456789ABCDEF' Do k=1 To things perm=first_word(first_word(substr(perm_elements,k,1) k)) dd.k=perm End Call .permSet 1 Return   .permSet: Procedure Expose dd. aa. things bunch perms thing. Parse Arg iteration If iteration>bunch Then do perm= aa.1 Do j=2 For bunch-1 perm= perm aa.j End perms+=1 If thing.1<>'' Then Do ol='' Do pi=1 To words(perm) z=word(perm,pi) If datatype(z)<>'NUM' Then z=9+pos(z,'ABCDEF') ol=ol thing.z End Say strip(ol) End Else Say perm End Else Do Do q=1 for things Do k=1 for iteration-1 If aa.k==dd.q Then iterate q End aa.iteration= dd.q Call .permSet iteration+1 End End Return   help: Parse Arg msg If msg<>'' Then Do Say 'ERROR:' msg Say '' End Say 'rexx perm -> Permutations of 1 2 3 ' Say 'rexx perm 2 -> Permutations of 1 2 ' Say 'rexx perm 2 4 -> Permutations of 1 2 3 4 in 2 positions' Say 'rexx perm 2 a b c d -> Permutations of a b c d in 2 positions' Exit
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Scala
Scala
def perfectInt(input: Int) = ((2 to sqrt(input).toInt).collect {case x if input % x == 0 => x + input / x}).sum == input - 1
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#Scheme
Scheme
(define (perf n) (let loop ((i 1) (sum 0)) (cond ((= i n) (= sum n)) ((= 0 (modulo n i)) (loop (+ i 1) (+ sum i))) (else (loop (+ i 1) sum)))))