/in/foo.cc: In function 'int main()':
/in/foo.cc:34:6: warning: unused variable 'm' [-Wunused-variable]
  int m,n;
      ^
/in/foo.cc:34:8: warning: unused variable 'n' [-Wunused-variable]
  int m,n;
        ^
/in/foo.cc:35:6: warning: unused variable 'a' [-Wunused-variable]
  int a[100];
      ^
/in/foo.cc:36:6: warning: unused variable 'b' [-Wunused-variable]
  int b[100];
      ^