/in/foo.cc: In function 'int main()':
/in/foo.cc:30:10: warning: unused variable 'sum' [-Wunused-variable]
  int A,B,sum=0,i;
          ^~~
/in/foo.cc:30:16: warning: unused variable 'i' [-Wunused-variable]
  int A,B,sum=0,i;
                ^