foo.c: In function 'main':
foo.c:6:17: warning: format '%d' expects argument of type 'int *', but argument 2 has type 'int' [-Wformat=]
    6 |         scanf("%d",n);
      |                ~^  ~
      |                 |  |
      |                 |  int
      |                 int *
foo.c:6:9: warning: 'n' is used uninitialized [-Wuninitialized]
    6 |         scanf("%d",n);
      |         ^~~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务