/in/foo.cc: In function 'int main()':
/in/foo.cc:3:5: error: 'cout' was not declared in this scope
    3 |     cout<<"O  O\n" ;
      |     ^~~~
/in/foo.cc:1:1: note: 'std::cout' is defined in header '<iostream>'; did you forget to '#include <iostream>'?
  +++ |+#include <iostream>
    1 | using namespace std;