foo.cc: In function 'int main()':
foo.cc:13:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   13 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~
foo.cc:14:41: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   14 |     for (int i = 1; i <= n; i ++ ) scanf("%d", &a[i]);
      |                                    ~~~~~^~~~~~~~~~~~~

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