/in/foo.c: In function 'main':
/in/foo.c:9:8: warning: too many arguments for format [-Wformat-extra-args]
  scanf("d",&x);
        ^~~
/in/foo.c:13:2: warning: 'n' may be used uninitialized in this function [-Wmaybe-uninitialized]
  ++n;
  ^~~