Quine

Quine

In computing, A quine is a program (a form of metaprogram) that produces its complete source code as its only output. For amusement, hackers sometimes attempt to develop the shortest possible quine in any given programming language.

Quines are named after W. V. Quine, who made an extensive study of indirect self-reference: he coined, among others, the paradox-producing expression, "yields falsehood when appended to its own quotation."

Table of contents

1 Sample quine in C
2 Sample quine in LISP
3 Sample quine in Python
4 Sample quine in Perl
5 Sample quine in BASIC
6 Sample quine in Pascal
7 Sample quine in Brainfuck
8 External links
9 See also

Sample quine in C

char x[]="char x[]=%c%s%c;%cint main() {printf(x,34,x,34,10,10);return 0;}%c";
int main() {printf(x,34,x,34,10,10);return 0;}

Sample quine in LISP

   ((lambda (x)
           (list x (list (quote quote) x)))
       (quote
           (lambda (x)
               (list x (list (quote quote) x)))))

Sample quine in Python

a='a=%s;print a%%`a`';print a%`a`

Sample quine in Perl

$_=q{$_=q{Q};s/Q/$_/;print};s/Q/$_/;print

Sample quine in BASIC

10 C=": PRINT CHR(49)+CHR(48)+CHR(32)+CHR(67)+CHR(61)+CHR(34)+C+CHR(34)+C":
   PRINT CHR(49)+CHR(48)+CHR(32)+CHR(67)+CHR(61)+CHR(34)+C+CHR(34)+C

Sample quine in Pascal

const a='const a=';b='begin write(a,#39,a,#39#59#98#61#39,b,#39#59#10,b) end.';
begin write(a,#39,a,#39#59#98#61#39,b,#39#59#10,b) end.

Sample quine in Brainfuck

(Note: This should be one continuous line of code, but line breaks have been added for ease of reading.)

->+>+++>>+>++>+>+++>>+>++>>>+>+>+>++>+>>>>+++>+>>++>+>+++>>++>++>>+>>+>++>++>
+>>>>+++>+>>>>++>++>>>>+>>++>+>+++>>>++>>++++++>>+>>++>+>>>>+++>>+++++>>+>+++
>>>++>>++>>+>>++>+>+++>>>++>>+++++++++++++>>+>>++>+>+++>+>+++>>>++>>++++>>+>>
++>+>>>>+++>>+++++>>>>++>>>>+>+>++>>+++>+>>>>+++>+>>>>+++>+>>>>+++>>++>++>+>+
++>+>++>++>>>>>>++>+>+++>>>>>+++>>>++>+>+++>+>+>++>>>>>>++>>>+>>>++>+>>>>+++>
+>>>+>>++>+>++++++++++++++++++>>>>+>+>>>+>>++>+>+++>>>++>>++++++++>>+>>++>+>>
>>+++>>++++++>>>+>++>>+++>+>+>++>+>+++>>>>>+++>>>+>+>>++>+>+++>>>++>>++++++++
>>+>>++>+>>>>+++>>++++>>+>+++>>>>>>++>+>+++>>+>++>>>>+>+>++>+>>>>+++>>+++>>>+
[[->>+<<]<+]+++++[->+++++++++<]>.[+]>>[<<+++++++[->+++++++++<]>-
.------------------->-[-<.<+>>]<[+]<+>>>]<<<[-[-[-[>>+<++++++[->+++++<]]>++++
++++++++++<]>+++<]++++++[->+++++++<]>+<<<-[->>>++<<<]>[->>.<<]<<]