foo.cc: In function 'int main()':
foo.cc:14:7: error: 'i' was not declared in this scope
  for (i = 0; i < n; i++)
       ^
foo.cc:19:7: error: 'i' was not declared in this scope
  for (i = 0; i < n; i++)
       ^
foo.cc:13:6: warning: unused variable 't' [-Wunused-variable]
  int t = 0;
      ^
foo.cc:5:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
  ~~~~~^~~~~~~~~~
foo.cc:9:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &a[i]);
   ~~~~~^~~~~~~~~~~~~

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