Quine：常见语言打印代码自身

自打印程序（Quine）是一种能够输出自身源代码的程序。以下是多种编程语言的实现：

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Python

s = 's = %r\nprint(s %% s)'
print(s % s)

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C

#include <stdio.h>
char *s = "#include <stdio.h>%cchar *s = %c%s%c;%cint main() { printf(s, 10, 34, s, 34, 10, 10); }";
int main() { printf(s, 10, 34, s, 34, 10, 10); }

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JavaScript

const s = "const s = %s; console.log(`const s = ${JSON.stringify(s)}; console.log(${s})`)";
console.log(`const s = ${JSON.stringify(s)}; console.log(${s})`);

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Java

public class Quine {
    public static void main(String[] args) {
        String s = "public class Quine {%c    public static void main(String[] args) {%c        String s = %c%s%c;%c        System.out.printf(s, 10, 10, 34, s, 34, 10, 10, 10);%c    }%c}";
        System.out.printf(s, 10, 10, 34, s, 34, 10, 10, 10);
    }
}

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Ruby

s = "s = %p; puts s %% s"
puts s % s

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C++

#include <cstdio>
#define Q(x) #x
#define S(x) Q(x)
const char* s = "#include <cstdio>%c#define Q(x) #x%c#define S(x) Q(x)%cconst char* s = %c%s%c;%cint main(){printf(s,10,10,10,34,s,34,10,10);}";
int main(){printf(s,10,10,10,34,s,34,10,10);}

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Go

package main
import "fmt"
func main() {
    s := "package main\nimport \"fmt\"\nfunc main() {\n    s := %q\n    fmt.Printf(s, s)\n}"
    fmt.Printf(s, s)
}

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Perl

$_=q{$_=q{%s};printf$_,$_};printf$_,$_

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