Question

I have a class hierarchy that’s three levels deep, like this:

class A {
public: 
    virtual ~A() {}

}

class B : public A {
public:
    virtual ~B() {}
    void foo(E *e) {
        e->remove(this);
    }
}

class C : public B {
public:
    ~C() {}
}

class E {
public:
    void remove(A *a) {
        delete a;
    }
}

Ok so what I am wondering is what happens when I call foo() on an object of C. Is it going to remove the entire object or only the B and A part of the object, and leave the C part still in memory?

Answer 1

Is it going to remove the entire object or only the B and A part of the object, and leave the C part still in memory?

No. It will “do the right thing” (that is, delete the most derived subobject, run all its destructors etc.) provided A (that is, the static type of the pointee of the pointer you delete) has a virtual destructor (and if class A has a virtual destructor, all its descendants have it, too). This holds for multiple inheritance, too.