/in/foo.c: In function 'Days':
/in/foo.c:14:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
/in/foo.c:13:2: warning: 'day' may be used uninitialized in this function [-Wmaybe-uninitialized]
  printf("%d",day);
  ^~~~~~~~~~~~~~~~