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3.4 KiB
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28 lines
3.4 KiB
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<?xml version="1.0" encoding="ISO-8859-1" standalone="no"?>
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<html xmlns="http://www.w3.org/1999/xhtml"><head><title>quine</title><link rel="stylesheet" href="../../jargon.css" type="text/css"/><meta name="generator" content="DocBook XSL Stylesheets V1.61.0"/><link rel="home" href="../index.html" title="The Jargon File"/><link rel="up" href="../Q.html" title="Q"/><link rel="previous" href="quick-and-dirty.html" title="quick-and-dirty"/><link rel="next" href="Quirk-objection.html" title="Quirk objection"/></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">quine</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="quick-and-dirty.html">Prev</a><EFBFBD></td><th width="60%" align="center">Q</th><td width="20%" align="right"><EFBFBD><a accesskey="n" href="Quirk-objection.html">Next</a></td></tr></table><hr/></div><dt><a id="quine"/><dt xmlns="" id="quine"><b>quine</b>: <span xmlns="http://www.w3.org/1999/xhtml" class="pronunciation">/kwi:n/</span>, <span xmlns="http://www.w3.org/1999/xhtml" class="grammar">n.</span></dt></dt><dd><p> [from the name of the logician Willard van Orman Quine, via Douglas
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Hofstadter] A program that generates a copy of its own source text as its
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complete output. Devising the shortest possible quine in some given
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programming language is a common hackish amusement. (We ignore some
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variants of BASIC in which a program consisting of a single empty string
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literal reproduces itself trivially.) Here is one classic quine:</p><table border="0" bgcolor="#E0E0E0"><tr><td><pre class="programlisting">
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((lambda (x)
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(list x (list (quote quote) x)))
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(quote
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(lambda (x)
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(list x (list (quote quote) x)))))
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</pre></td></tr></table><p>This one works in LISP or Scheme. It's relatively easy to write
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quines in other languages such as Postscript which readily handle programs
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as data; much harder (and thus more challenging!) in languages like C
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which do not. Here is a classic C quine for ASCII machines:</p><table border="0" bgcolor="#E0E0E0"><tr><td><pre class="programlisting">
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char*f="char*f=%c%s%c;main()
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{printf(f,34,f,34,10);}%c";
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main(){printf(f,34,f,34,10);}
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</pre></td></tr></table><p>For excruciatingly exact quinishness, remove the interior line
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breaks. Here is another elegant quine in ANSI C:</p><table border="0" bgcolor="#E0E0E0"><tr><td><pre class="programlisting">
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#define q(k)main(){return!puts(#k"\nq("#k")");}
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q(#define q(k)main(){return!puts(#k"\nq("#k")");})
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</pre></td></tr></table><p>Some infamous <a href="../O/Obfuscated-C-Contest.html"><i class="glossterm">Obfuscated C Contest</i></a> entries
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have been quines that reproduced in exotic ways. There is an amusing
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<a href="http://www.nyx.org/~gthompso/quine.htm" target="_top"> Quine Home
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Page</a>.</p></dd><div class="navfooter"><hr/><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="quick-and-dirty.html">Prev</a><EFBFBD></td><td width="20%" align="center"><a accesskey="u" href="../Q.html">Up</a></td><td width="40%" align="right"><EFBFBD><a accesskey="n" href="Quirk-objection.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">quick-and-dirty<74></td><td width="20%" align="center"><a accesskey="h" href="../index.html">Home</a></td><td width="40%" align="right" valign="top"><EFBFBD>Quirk objection</td></tr></table></div></body></html>
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