C++: Copy object data in member function of base class

Question

Suppose I have two classes A, and B. B is derived from A. A has no data members, however B has two integer members.

If I define a method in class A, like the following:

void CopyFrom( const A* other )
{
    *this = *other;
}

And call it in the child class, will the integer data member get copied?

Answer 1

No. This is known as the slicing problem.

This is true even if you overload operator= in both A and B: *this = *other will only ever resolve to A::operator=(const A&) or B::operator=(const A&) being called.