/in/foo.cc: In function 'int gongyue(int, int)':
/in/foo.cc:19:9: warning: 'yue' may be used uninitialized in this function [-Wmaybe-uninitialized]
  return yue;
         ^~~
/in/foo.cc: In function 'int gongbei(int, int)':
/in/foo.cc:28:5: warning: 'yue' may be used uninitialized in this function [-Wmaybe-uninitialized]
  bei=a*b/yue;
  ~~~^~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:37:26: warning: 'yue' may be used uninitialized in this function [-Wmaybe-uninitialized]
  printf("%d\n%d",yue,bei);
                          ^
/in/foo.cc:28:5: warning: 'yue' may be used uninitialized in this function [-Wmaybe-uninitialized]
  bei=a*b/yue;
  ~~~^~~~~~~~
/in/foo.cc:4:6: note: 'yue' was declared here
  int yue;
      ^~~