/in/foo.cc: In function 'int main()':
/in/foo.cc:6:13: warning: unused variable 'i' [-Wunused-variable]
    6 |         int i, j, k, n,sum,r;
      |             ^
/in/foo.cc:6:16: warning: unused variable 'j' [-Wunused-variable]
    6 |         int i, j, k, n,sum,r;
      |                ^
/in/foo.cc:6:19: warning: unused variable 'k' [-Wunused-variable]
    6 |         int i, j, k, n,sum,r;
      |                   ^
/in/foo.cc:6:22: warning: unused variable 'n' [-Wunused-variable]
    6 |         int i, j, k, n,sum,r;
      |                      ^