Inheritence ambiguity

This is a discussion on Inheritence ambiguity within the C++ Programming forums, part of the General Programming Boards category; I have a base class A, which is publicly inherited by both B and C. D is a class that ...

  1. #1
    mustang benny bennyandthejets's Avatar
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    Inheritence ambiguity

    I have a base class A, which is publicly inherited by both B and C. D is a class that public inherits B and C. There is some ambiguity when I make a certain function call.
    Code:
    #include <iostream>
    using namespace std;
    
    class A
    {
    private:
        int Aint;
    public:
        A():Aint(1) {}
        ~A() {}
        virtual int GetAint(void) {cout << "A::GetAint()" << endl; return Aint; }
    };
    
    class B : public A
    {
    private:
        int Bint;
    public:
        B():Bint(2) {}
        ~B() {}
        virtual int GetBint(void) {return Bint; }
        virtual int GetAint(void) {cout << "B::GetAint()" << endl; return A::GetAint(); }
    };
    
    class C : public A
    {
    private:
        int Cint;
    public:
        C():Cint(3) {}
        ~C() {}
        virtual int GetCint(void) {return Cint; }
        virtual int GetAint(void) {cout << "C::GetAint()" << endl; return A::GetAint(); }
    };
    
    class D : public B, public C
    {
    private:
        int Dint;
    public:
        D():Dint(4) {}
        ~D() {}
        virtual int GetDint(void) {return Dint; }
    };
    
    int main(void)
    {
        D d;
        int temp;
    
        temp=d.GetAint();
        cout << temp << endl;
    
        return 0;
    }
    The call 'd.GetAint()' is ambiguous, and rightly so, because that was the plan all along. My question is, what is the work around here? Can I specify in main() to call a particular inherited function, something like:
    Code:
    temp=d.C:GetAint();
    I know that's not correct but is this possible?

    I am also aware that I could just place a function in D and call whichever one I wanted.
    Last edited by bennyandthejets; 12-04-2003 at 05:09 PM.
    benforbes@optusnet.com.au
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  2. #2
    carry on JaWiB's Avatar
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    Not sure if its really correct, but this does seem to work...

    Code:
    temp=d.B::GetAint();
    When I change to that, my output is like this:

    B::GetAint()
    A::GetAint()
    1
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  3. #3
    mustang benny bennyandthejets's Avatar
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    Ha! I didn't think it was so easy, so I didn't even try that. Thanks. Now for the crunch question: find me a real life application of classes that would result in this kind of ambiguity.
    benforbes@optusnet.com.au
    Microsoft Visual Studio .NET 2003 Enterprise Architect
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  4. #4
    mustang benny bennyandthejets's Avatar
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    What about this:
    Code:
    temp=d.B.A::GetAint();
        cout << temp << endl;
    Using the same classes as before. Seeing as A::GetAint() is publicly inherited throughout, it should be possible to access it from an instance of D. What is the syntax for this?
    benforbes@optusnet.com.au
    Microsoft Visual Studio .NET 2003 Enterprise Architect
    Windows XP Pro

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