/in/foo.c: In function 'change':
/in/foo.c:51:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
/tmp/ccagMGlF.o: In function `main':
foo.c:(.text.startup+0x8b): undefined reference to `MaoPaiXu'
collect2: error: ld returned 1 exit status