C++ cannot convert from base A to derived type B via virtual base A

Question

I have three classes:

class A {};

class B : virtual public A {};
class C : virtual public A {};

class D: public B, public C {};

Attemptin

Answer 1

You can't use static_cast in this situation because the compiler doesn't know the offset of B relative to A at compile time. The offset must be calculated at run-time based on the exact type of the most derived object. Therefore you must use dynamic_cast.