foo.cc: In function 'void Output(int*, int)':
foo.cc:44:3: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   44 |   cout << a[i] << " ";
      |   ^~~~
      |   std::cout
In file included from foo.cc:5:
/usr/include/c++/9/iostream:61:18: note: 'std::cout' declared here
   61 |   extern ostream cout;  /// Linked to standard output
      |                  ^~~~
foo.cc:46:2: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   46 |  cout << endl;
      |  ^~~~
      |  std::cout
In file included from foo.cc:5:
/usr/include/c++/9/iostream:61:18: note: 'std::cout' declared here
   61 |   extern ostream cout;  /// Linked to standard output
      |                  ^~~~
foo.cc:46:10: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   46 |  cout << endl;
      |          ^~~~
      |          std::endl
In file included from /usr/include/c++/9/iostream:39,
                 from foo.cc:5:
/usr/include/c++/9/ostream:599:5: note: 'std::endl' declared here
  599 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
foo.cc: At global scope:
foo.cc:48:1: error: '::main' must return 'int'
   48 | void main()
      | ^~~~
foo.cc: In function 'int main()':
foo.cc:52:2: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
   52 |  cin >> n1;
      |  ^~~
      |  std::cin
In file included from foo.cc:5:
/usr/include/c++/9/iostream:60:18: note: 'std::cin' declared here
   60 |   extern istream cin;  /// Linked to standard input
      |                  ^~~

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