C++子类继承

Question

Ok, this might be silly question but I can't figure out how to fix my problem.

Let's assume we have 4 classes

1. class A is a Base class
2. class B is derived from A with new methods (no override)
3. class C is derived from A
4. class D is derived from B (and also from A for inheritance)

my question is: how do I use a method defined in B in D? If D inherit from BI get "error: member 'xxx' found in multiple base classes of different types" if D does not inherit from BI get "use of undeclared identifier"

Answer 1

Here's how it's done - based on your description:

class A {
protected:
    void foo();
};

class B : public A {
protected:
    void bar();
};

class D : public B {
protected:
    void baz() { B::bar(); }
};

Note that you should not have D inherit from A directly, except in very specific and rare cases. Inheritance is transitive.

Also, next time, Please post a Minimal, Complete, and Verifiable example and don't make us guess what you mean exactly.

In those cases in which the same method is available from the same subclasses from multiple inheritance paths are the "Diamond Pattern", and you can read about it here .