Include headers in header file?

Question

I have several libraries made by myself (a geometry library, a linked list library, etc). I want to make a header file to include them all in one lib.h. Could I do something

Answer 1

The "right way" to include _{(in 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 parameter, 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;

_{From a cplusplus.com article you should definitively read}