/in/foo.c: In function 'main':
/in/foo.c:20:21: error: expected expression before 'double'
  printf("%.2f%%\n", double(cnt1 *100/ n ));
                     ^~~~~~
/in/foo.c:21:21: error: expected expression before 'double'
  printf("%.2f%%\n", double(cnt2 *100/ n ));
                     ^~~~~~
/in/foo.c:22:21: error: expected expression before 'double'
  printf("%.2f%%\n", double(cnt3 *100/ n ));
                     ^~~~~~
/in/foo.c:23:21: error: expected expression before 'double'
  printf("%.2f%%\n", double(cnt4 *100/ n ));
                     ^~~~~~