virtual prototype in a class

This is a discussion on virtual prototype in a class within the C++ Programming forums, part of the General Programming Boards category; Hello I have this base class: Code: 1. class base 2. { 3. private: 4. ..... 5. public: 6. .... ...

  1. #1
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    virtual prototype in a class

    Hello
    I have this base class:

    Code:
    1. class base
    2. {
    3. private:
    4. .....
    5. public:
    6. ....
    7. virtual void test() = 0:
    8. }
    My questions:
    1. Why i be force to write "= 0" in line seven
    2. It's with line seven a pure abstract class so i can't create a object of the base class. But why it's a pure abstract class?

    regards

    sphreak

  2. #2
    Confused Magos's Avatar
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    You don't have to write '= 0', but doing so makes it a pure virtual class which you can't create objects from (without inheriting from it).
    MagosX.com

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  3. #3
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    hmm...
    so it haven't some reason because of memory managment or other reason?
    the compiler know it when there is a line how this in the class, that the class is a pure virtual class?

  4. #4
    Cat without Hat CornedBee's Avatar
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    If you don't put the =0 there the linker will search for an implementation of the method and, failing to find one, refuse to link the app.
    All the buzzt!
    CornedBee

    "There is not now, nor has there ever been, nor will there ever be, any programming language in which it is the least bit difficult to write bad code."
    - Flon's Law

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