foo.cc: In function 'int main()':
foo.cc:5:2: error: 'cin' was not declared in this scope
    5 |  cin >> a >> b >> c;
      |  ^~~
foo.cc:1:1: note: 'std::cin' is defined in header '<iostream>'; did you forget to '#include <iostream>'?
  +++ |+#include <iostream>
    1 | using namespace std;
foo.cc:21:2: error: 'cout' was not declared in this scope
   21 |  cout << a << " " << b << " " << c << endl;
      |  ^~~~
foo.cc:21:2: note: 'std::cout' is defined in header '<iostream>'; did you forget to '#include <iostream>'?
foo.cc:21:39: error: 'endl' was not declared in this scope
   21 |  cout << a << " " << b << " " << c << endl;
      |                                       ^~~~
foo.cc:1:1: note: 'std::endl' is defined in header '<ostream>'; did you forget to '#include <ostream>'?
  +++ |+#include <ostream>
    1 | using namespace std;

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