Thread: When to forward reference and when to include?

Headers and Includes: Why and How says -

If, for example, class A uses class B, then class B is one of class A's dependencies. Whether it can be forward declared or needs to be included depends on how B is used within A:

- do nothing if: A makes no references at all to B
- do nothing if: The only reference to B is in a friend declaration
- forward declare B if: A contains a B pointer or reference: B* myb;
- forward declare B if: one or more functions has a B object/pointer/reference
as a parementer, or as a return type: B MyFunction(B myb);
- #include "b.h" if: B is a parent class of A
- #include "b.h" if: A contains a B object: B myb;

Is it as simple as that or is there something more to it?

:+1: Thank you very much.