foo.cc: In function 'int main()':
foo.cc:8:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    8 |     scanf("%d",&n);
      |     ~~~~~^~~~~~~~~
foo.cc:10:13: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   10 |        scanf("%d",&a[i]);
      |        ~~~~~^~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务