/in/foo.cc: In function 'int main()':
/in/foo.cc:19:12: warning: right operand of comma operator has no effect [-Wunused-value]
  cin>>n1,n2;
            ^
/in/foo.cc:18:9: warning: 'n2' may be used uninitialized in this function [-Wmaybe-uninitialized]
  int n1,n2;
         ^~