/in/foo.cc: In function 'int main()':
/in/foo.cc:6:13: warning: unused variable 'a' [-Wunused-variable]
    6 |         int a,b,c,n;
      |             ^
/in/foo.cc:6:15: warning: unused variable 'b' [-Wunused-variable]
    6 |         int a,b,c,n;
      |               ^
/in/foo.cc:6:17: warning: unused variable 'c' [-Wunused-variable]
    6 |         int a,b,c,n;
      |                 ^