/in/foo.cc: In function 'int main()':
/in/foo.cc:10:6: warning: unused variable 'n' [-Wunused-variable]
  int n, m, i=0;
      ^
/in/foo.cc:10:9: warning: unused variable 'm' [-Wunused-variable]
  int n, m, i=0;
         ^
/in/foo.cc:10:12: warning: unused variable 'i' [-Wunused-variable]
  int n, m, i=0;
            ^