/in/foo.cc: In function 'int main()':
/in/foo.cc:4:10: warning: unused variable 'a' [-Wunused-variable]
  int abc,a,b,c;
          ^
/in/foo.cc:4:12: warning: unused variable 'b' [-Wunused-variable]
  int abc,a,b,c;
            ^
/in/foo.cc:4:14: warning: unused variable 'c' [-Wunused-variable]
  int abc,a,b,c;
              ^