Changing an inherited function

This is a discussion on Changing an inherited function within the C++ Programming forums, part of the General Programming Boards category; Hello. I have a class called CMinion, which inherits from CEnemy. CEnemy gives CMinion a Render() function, still CMinion wants ...

  1. #1
    Hail to the king, baby. Akkernight's Avatar
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    Changing an inherited function

    Hello.

    I have a class called CMinion, which inherits from CEnemy.
    CEnemy gives CMinion a Render() function, still CMinion wants to change this Render() function a little by adding a little something. How do I let CMinion change the Render() function? I've seen it done somewhere I believe...

    More in detail. CEnemy's Render() function renders body parts, but CMinion wants to render an outfit too... Like, some extra things only CMinion is allowed to wear...

    I ain't fully sure how to explain this, but hope you people get it :P

    Thanks in advance!
    Currently research OpenGL

  2. #2
    C++ Witch laserlight's Avatar
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    Quote Originally Posted by Akkernight
    CEnemy gives CMinion a Render() function, still CMinion wants to change this Render() function a little by adding a little something. How do I let CMinion change the Render() function?
    What do you mean by "adding a little something", and is Render() a virtual function?

    Quote Originally Posted by Akkernight
    CEnemy's Render() function renders body parts, but CMinion wants to render an outfit too.
    What are "body parts" and "outfit"?

    Basically, if Render() is a virtual function, then CMinion can override it. But if you need to change the signature of Render(), then either way you have to overload rather than override.
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  3. #3
    Kernel hacker
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    So, you have:
    Code:
    class CEnemy
    {
    public:
       virtual void Render(...);
    };
    
    class CMinion : public CEnemy
    {
    public:
       virtual void Render(...);
    }
    Ok so far?

    Then you want CMinion to do something MORE than CEnemy's render, but ALSO do CEnemy's render without having to dublicate all the code?

    Code:
    void CMinion::Render(...)
    {
       // Do CMinion specifc render operation. 
      CEnemy::Render(...);
      // Possibly more CMinion specific rendering. 
    }
    is the usual way to do this.

    Of course, if you have to do things in the middle of, you either have to split the render into two parts and make member two functions.

    The other solution is to have CEnemy::Render() call another virtual member function, which does different things when called on CMinion than on CEnemy.

    --
    Mats
    Compilers can produce warnings - make the compiler programmers happy: Use them!
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  4. #4
    Hail to the king, baby. Akkernight's Avatar
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    Awesome, thanks!
    This was my code...
    Code:
    void CMinion::Render(){
    
    	CSprite::Render();
    	outfit.Render();
    
    }
    ofc, CEnemy got Render() inherited by a pretty long inheritance list, but I didn't wanna get into all that :P
    Currently research OpenGL

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