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From: williams_j@apollo.HP.COM (Jim Williams)
Newsgroups: comp.lang.c++
Subject: Re: Derived can't access protected members of base's
Message-ID: <49548fe5.20b6d@apollo.HP.COM>
Date: 21 Mar 90 18:10:00 GMT
References: <56.UUL1.3#5109@pantor.UUCP> <10593@alice.UUCP>
Sender: root@apollo.HP.COM
Lines: 32

Andrew Koenig writes (6443):

>  For example:
>  
>  	class Foo {
>  	protected:
>  		int i;
>  	};
>  
>  Now, suppose I want to clobber member `i' of a `foo' object.  I would
>  like to write this:
>  
>  	void clobber(Foo& f, int n) { f.i = n; }
>  
>  but I can't quite do that directly.  What if I do this, though?
>  
>  	class dummy: public Foo { friend void clobber(Foo&, int); };
>  
>  Now `dummy' can get at any protected member of Foo, and so can its
>  friends.  By making `clobber' a friend, I open Foo up to it, and
>  completely without permission from the author of Foo.

Couldn't you also write:

     class FooPub {
     public:
       int i;
     };

     void clobber (Foo& f, int n) { ((FooPub*)&f)->i = n; }

Why have private/protected members at all? :-)