混淆的C代码竞赛2006.请解释sykes2.c

问题：

How does this C program work? 这个C程序如何工作？

main(_){_^448&&main(-~_);putchar(--_%64?32|-~7[__TIME__-_/8%8][">'txiZ^(~z?"-48]>>";;;====~$::199"[_*2&8|_/64]/(_&2?1:8)%8&1:10);}

It compiles as it is (tested on gcc 4.6.3 ). 它按原样编译（在gcc 4.6.3上测试）。 It prints the time when compiled. 它打印编译时的时间。 On my system: 在我的系统上：

    !!  !!!!!!              !!  !!!!!!              !!  !!!!!! 
    !!  !!  !!              !!      !!              !!  !!  !! 
    !!  !!  !!              !!      !!              !!  !!  !! 
    !!  !!!!!!    !!        !!      !!    !!        !!  !!!!!! 
    !!      !!              !!      !!              !!  !!  !! 
    !!      !!              !!      !!              !!  !!  !! 
    !!  !!!!!!              !!      !!              !!  !!!!!!

Source: sykes2 - A clock in one line , sykes2 author hints 资料来源： sykes2 - 一行中的一个时钟， sykes2作者提示

Some hints: No compile warnings per default. 一些提示：默认情况下没有编译警告。 Compiled with -Wall , the following warnings are emitted: 使用-Wall编译，会发出以下警告：

sykes2.c:1:1: warning: return type defaults to ‘int’ [-Wreturn-type]
sykes2.c: In function ‘main’:
sykes2.c:1:14: warning: value computed is not used [-Wunused-value]
sykes2.c:1:1: warning: implicit declaration of function ‘putchar’ [-Wimplicit-function-declaration]
sykes2.c:1:1: warning: suggest parentheses around arithmetic in operand of ‘|’ [-Wparentheses]
sykes2.c:1:1: warning: suggest parentheses around arithmetic in operand of ‘|’ [-Wparentheses]
sykes2.c:1:1: warning: control reaches end of non-void function [-Wreturn-type]

解决方案：

参考一： https://stackoom.com/question/12aXJ/混淆的C代码竞赛-请解释sykes-c
参考二： https://oldbug.net/q/12aXJ/Obfuscated-C-Code-Contest-2006-Please-explain-sykes2-c

来源：oschina

链接：https://my.oschina.net/u/4432649/blog/4317096

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