/in/foo.cc: In function 'int simplify(int, int)':
/in/foo.cc:24:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
/in/foo.cc:22:7: warning: 'j' may be used uninitialized in this function [-Wmaybe-uninitialized]
 printf("%d %d",m/j,n/j);//分数约分
 ~~~~~~^~~~~~~~~~~~~~~~~