/in/foo.cc: In function 'int main()':
/in/foo.cc:6:9: warning: unused variable 'a' [-Wunused-variable]
    6 |     int a,b;
      |         ^
/in/foo.cc:6:11: warning: unused variable 'b' [-Wunused-variable]
    6 |     int a,b;
      |           ^