Question:
Why do I need private inheritance in C++?Is it true that (in C++) function parameters are pushed onto the stack from right to left? If so, why?

Answer:
Use private inheritance whenever you want to reuse code from aclass. Private inheritance can often be replaced with containment.Sometimes it is useful to convert the derived class pointer to a base class pointer inside the derived class. Private inheritance is useful insuch cases.

The C++ language does not specify how the parameters are pushed on the stack. Implementations are free to choose any form theywant.