/in/foo.c: In function 'main':
/in/foo.c:13:12: warning: unused variable 'd' [-Wunused-variable]
  int a,b,c,d,t,sum;
            ^
/in/foo.c:13:10: warning: unused variable 'c' [-Wunused-variable]
  int a,b,c,d,t,sum;
          ^