C ++多级继承函数调用

Question

Consider multilevel inheritance between C++ classes. Consider:

struct A { 
    void Dummy1() { }
};

struct B : A { 
    void Dummy1() { }
};

struct C : B {
    void Dummy() { 
        Dummy1(); 
    }

    void Dummy1() { }
};

struct D : C { 
    void Dummy1() { }
};

struct E : D { 
    void Dummy1() { }
};

Given:

E e;
e.Dummy();

I want to know which Dummy1 would be called. The one defined in class C or the one defined in class E ?

Also, I get very confused in function call made in multilevel inheritance, like in case of virtual functions etc. Can some one suggest a book or article which can help me in understanding this. I googled a lot but was not able to find anything helpful.

Thanks in advance.

Answer 1

I want to know which Dummy1 would be called. The one defined in class C or the one defined in class E ?

Given your code, it will call the one defined in C .

If you want it to call the one defined in E , you'll have to make Dummy1 a virtual function.

Answer 2

The principle you want to learn is called polymorphism .

If the Dummy1() is defined as virtual in all classes then the version will be used which is defined in the exact class of the object, ie in your case E::Dummy() .

However in your code it is not virtual that's why you will have C::Dummy() called

Mind that most compilers will give a warning that you're overriding a function if virtual is not provided when inheriting (and function definition matches)