Question

I’m trying to create the constructor of a nested class, which inherits from a parent nested class, using its constructor. Basically:

DerivedList<T>::DerivedNested::DerivedNested(DerivedNode*& ptr)
  : BaseList<T>::BaseNested::BaseNested(ptr)
{}

The prototype of the constructor of my BaseNested goes like this:

BaseList<T>::BaseNested::BaseNested(BaseNode*& ptr)

(and is required to get the ptr parameter by reference since it needs the address of said pointer in its code)

I figured I had to cast my DerivedNode* to a BaseNode*, but : a static_cast::BaseNode*>(ptr) finds no matching functions since it isn’t a reference, and a static_cast::BaseNode*&>(ptr) gives an invalid cast error.

The same goes for dynamic_cast. A reinterpret_cast compiles, but gives something incorrect during excecution.

Does anyone know how I could call that parent constructor?

Answer 1

If you think you need a reference, that’s probably because you want to modify the pointer later. The problem is that the type of the pointer in the derived class is DerivedNode*, and BaseNode* in the base class. What if the base class affects a DerivedNode2* to its pointer ?

You should use setters, or move the logic from the base class to the derived ones.