/in/foo.cc: In function 'int maxyinshu(int, int)':
/in/foo.cc:13:9: warning: 'y' may be used uninitialized in this function [-Wmaybe-uninitialized]
  return y;
         ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:36:24: warning: 'y' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<maxyinshu(a,b)<<"\n"<<minbeishu(a,b);
                        ^~~~