foo.c: In function 'main':
foo.c:17:6: error: 'i' undeclared (first use in this function)
   17 |  for(i=0;m<n;m++)
      |      ^
foo.c:17:6: note: each undeclared identifier is reported only once for each function it appears in
foo.c:16:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   16 |   scanf("%d",&n);
      |   ^~~~~~~~~~~~~~
foo.c:19:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   19 |   scanf("%d",&a[m]);
      |   ^~~~~~~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务