/in/foo.cc: In function 'int main()':
/in/foo.cc:30:10: warning: unused variable 'j' [-Wunused-variable]
  int m,i,j,a[100],s,sum;
          ^
/in/foo.cc:30:21: warning: unused variable 'sum' [-Wunused-variable]
  int m,i,j,a[100],s,sum;
                     ^~~