foo.cc: In function ‘int main()’:
foo.cc:6:17: warning: ‘m’ is used uninitialized [-Wuninitialized]
    6 |         cout<<m*n;
      |                 ^
foo.cc:5:14: note: ‘m’ was declared here
    5 |         long m,n;
      |              ^
foo.cc:6:17: warning: ‘n’ is used uninitialized [-Wuninitialized]
    6 |         cout<<m*n;
      |                 ^
foo.cc:5:16: note: ‘n’ was declared here
    5 |         long m,n;
      |                ^