/in/foo.cc: In function 'int main()':
/in/foo.cc:7:4: error: 'cout' was not declared in this scope
    7 |    cout << "######\n";
      |    ^~~~
/in/foo.cc:2:1: note: 'std::cout' is defined in header '<iostream>'; did you forget to '#include <iostream>'?
    1 | #include <stdio.h>
  +++ |+#include <iostream>
    2 | using namespace std;