Xref: utzoo comp.lang.c++:12828 comp.std.c++:821 comp.object:3130
Newsgroups: comp.lang.c++,comp.std.c++,comp.object
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From: fuchs@t500e0.telematik.informatik.uni-karlsruhe.de (Harald Fuchs)
Subject: Re: C++ possible new construct proposal
Message-ID: <fuchs.671459891@t500e0>
Sender: news@ira.uka.de (USENET News System)
Organization: University of Karlsruhe, FRG
References: <1991Apr11.155803.5410@mnemosyne.cs.du.edu>
Date: Fri, 12 Apr 1991 12:38:11 GMT
Lines: 62

cag@mnemosyne.cs.du.edu (Chris Gantz) writes:

>        class X {
>         type:
>                private:
>                     // internal data representation for type;
>		     int no_instantiations;
>                protected:
>                     // protected interface for type;
>                public:
>		     int instantaitions() {
>		        return instantiations;
>		     }
>		     void update_instantiations() {
>			 no_instantitations++;
>		     }
>         object:
>                private: 
>                     // internal data representation for objects; 
>                protected: 
>                     // protected interface for objects;
>                public: 
>                    X() { // default constructor 
>                          update_instantiations() 
>			  // object appropriate internal data initialization.
>		    } 
>                   ~X() { } 
>		    void f() { }
>        };


>	main()
>	{
>	    X x_obj;

>	    x_obj.f(); // using x_obj through the object public interface
>	    // below is an example of using the type X as an object...
>	    no_current_instantiations = X.instantiations();
>	    
>	}

Your proposed addition has been done in C++ version 2.
It's called "static member functions":

class X {
  static int no_instantiations;
  static void update_instantiations() { no_instantitations++; }
public:
  X () { update_instantiations(); }
  static int instantiations () { return no_instantiations; }
  void f ();
};

main () {
  X x_obj;
  x_obj.f ();
  no_current_instantiations = X::instantiations ();
    // or x_obj.instantiations ()
}
--

Harald Fuchs <fuchs@t500e0.telematik.informatik.uni-karlsruhe.de>