cout and ofstream

[Whovian]

Just to be clear, from what I've tested, if I'm right, ofstream inherits from ostream, and cout is an ostream? And polymorphic behaviour occurs here with the rdbuf(/*Whatever type's returned by the rdbuf() method*/) method, so ofstream's version is private or protected and can't be accessed directly (but it can be accessed via ostream::rdbuf, of course)?

[Cubbi]

ofstream inherits from ostream

yes

and cout is an ostream

Yes, with clarification that "is a" is an OOP relationship: the runtime type of std::cout is some implementation-defined type, derived from std::ostream.

And polymorphic behaviour occurs here with the rdbuf

Kind of:
std::ostream implements formatted I/O interface (operator>>, put, write) in terms of the public interface of std::streambuf (which calls virtual member functions of std::streambuf, which is where polymorphic behavior occurs)

std::ofstream implements file-specific interface (open, close) in terms of the public interface of std::filebuf.