/in/foo.cc: In function 'int main()':
/in/foo.cc:11:8: warning: unused variable 'j' [-Wunused-variable]
  int i,j,k,m,n;
        ^
/in/foo.cc:11:10: warning: unused variable 'k' [-Wunused-variable]
  int i,j,k,m,n;
          ^