foo.cc: In function 'int main()':
foo.cc:6:6: error: 'itn' was not declared in this scope; did you mean 'int'?
    6 |  for(itn i = 1; i <= n / 2; i++)
      |      ^~~
      |      int
foo.cc:6:17: error: 'i' was not declared in this scope
    6 |  for(itn i = 1; i <= n / 2; i++)
      |                 ^
foo.cc:5:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    5 |  scanf("%d", &n);
      |  ~~~~~^~~~~~~~~~

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