/in/foo.c: In function 'FS':
/in/foo.c:6:6: warning: unused variable 'j' [-Wunused-variable]
  int j = x;
      ^
/in/foo.c: In function 'main':
/in/foo.c:17:6: warning: unused variable 'count' [-Wunused-variable]
  int count = 0;
      ^~~~~
/in/foo.c:16:9: warning: unused variable 'i' [-Wunused-variable]
  int n, i;
         ^