foo.cc: In function 'int main()':
foo.cc:39:14: error: 'hi' was not declared in this scope
   39 |         ans+=hi();
      |              ^~
foo.cc:24:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   24 |     scanf("%d",&n);
      |     ~~~~~^~~~~~~~~
foo.cc:27:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   27 |         scanf("%d",&a[i]);
      |         ~~~~~^~~~~~~~~~~~

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