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produces a copy of its own source code

In computing, a quine is a computer program which produces a copy of its own source code as its only output.

perl

seek DATA,0,0;
print <DATA>;
__DATA__
Cheating quine.

$_=q(print qq(\$_=q($_);eval\n));eval

$x=q($x=q(%s);printf($x,$x););printf($x,$x);

java

public class Quine {public static void main(String[] args) {String s = "public class Quine {public static void main(String[] args) {String s = %c%s%c;System.out.printf(s, 34, s, 34);}}";System.out.printf(s, 34, s, 34);}}

public class Quine {
public static void main(String[] args) {
Character cq = (char) 34;
Character cn = (char) 10;
Character cs = (char) 92;
String s = "public class Quine {\n public static void main(String[] args) {\n Character cq = (char) 34;\n Character cn = (char) 10;\n Character cs = (char) 92;\n String s = %c%s%c;\n System.out.printf(s, cq, s.replace(cn.toString(), cs.toString() + 'n'), cq);\n }\n}";
System.out.printf(s, cq, s.replace(cn.toString(), cs.toString() + 'n'), cq);
}
}

cpp

#include <cstdio>
#define B(x) x; printf("{ B(" #x ") }\n");
int main()
{ B(printf("#include <cstdio>\n#define B(x) x; printf(\"{ B(\" #x \") }\\n\");\nint main()\n")) }