Multiple Definition Error

[aboutjeab]

Hi,

I am trying to make use of some inherited class & function (e.g. class X, function abc()) from other parent classes (e.g. class A,B), unfortunately, I have got 'multiple definition' error whlie compliling.

//AAA.h
class A {
public :
virtual void abc();
}

class X : public A {
public :
void abc();
}

//AAA.cc
void X::abc() {
}

//BBB.h
class B {
public :
virtual void abc();
}

class X : public B {
public :
void abc();
}

//BBB.cc
void X::abc() {
}

how can I refer to the parent classes A,B while calling the abc() function?

Thank you for any clue..
J

[helios]

You're defining X twice. One derives from A and the other from B.

[aboutjeab]

But in the case, i need to define X twice for different A and B (some functions in X may be different).

Is it possible to call the abc() function something like...

void A::X::abc() {}

Thank you for your answer.

[helios]

If they derive from different classes and have different functions, it doesn't make much sense to give them the same names, now does it? And no, you can't refer to X like that, since it's being defined in the global scope. You could do this:

class A{
    class X{
        //...
    };
};

But then you can't have it derive from A (I think).

The :: operator is used to refer to functions, variables, objects or classes defined in a class or namespace, not to do what you did there. There can only be one unique identifier (although functions have a different rule in C++) in each namespace, so that syntax wouldn't be that useful, anyway.