foo.cc: In function ‘int gys(int, int)’:
foo.cc:5:9: warning: variable ‘m’ set but not used [-Wunused-but-set-variable]
    5 |     int m,n;//m表示商，n表示余数
      |         ^
foo.cc: In function ‘int main()’:
foo.cc:33:15: warning: ‘x’ may be used uninitialized [-Wmaybe-uninitialized]
   33 |         cout<<x<<endl;
      |               ^
foo.cc:22:15: note: ‘x’ was declared here
   22 |         int n,x;
      |               ^