/in/foo.c: In function 'main':
/in/foo.c:7:9: warning: zero-length gnu_printf format string [-Wformat-zero-length]
  printf("");
         ^~
/in/foo.c:6:6: warning: 'x' is used uninitialized in this function [-Wuninitialized]
  int xx=x,y=0;
      ^~