foo.c: In function 'main':
foo.c:21:25: warning: format '%d' expects argument of type 'int *', but argument 2 has type 'int' [-Wformat=]
   21 |                 scanf("%d",a[i]);
      |                        ~^  ~~~~
      |                         |   |
      |                         |   int
      |                         int *
foo.c:21:17: warning: 'a' may be used uninitialized [-Wmaybe-uninitialized]
   21 |                 scanf("%d",a[i]);
      |                 ^~~~~~~~~~~~~~~~
foo.c:16:13: note: 'a' declared here
   16 |         int a[1000];
      |             ^

[Hydro](https://hydro.ac)提供评测服务