A Static_cast<> Question

This is a discussion on A Static_cast<> Question within the C++ Programming forums, part of the General Programming Boards category; Suppose Code: class Derived: public Base{ ... }; what is the difference between: Code: Derived * d = new Derived; ...

  1. #1
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    A Static_cast<> Question

    Suppose

    Code:
    class Derived: public Base{
    ...
    };
    what is the difference between:


    Code:
    Derived * d = new Derived;
    Base* b = static_cast<Base*>(d);
    AND


    Code:
    Derived  d ;
    Base b = static_cast<Base>(d);
    Last edited by meili100; 06-07-2007 at 12:07 PM.

  2. #2
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    Polymorphic relationships don't hold for actual objects.

    That is:

    A Derived* is a Base*
    A Derived& is a Base&

    But a Derived is NOT a Base. Such a conversion results in slicing, and you lose pieces of your objects.
    There is no greater sign that a computing technology is worthless than the association of the word "solution" with it.

  3. #3
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    The second one makes a copy of the object and casts it (which is where the slicing happens). The first one makes a copy of the pointer and casts it, so the object is still there.

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