Re: Why doesn't this multiple virtual inheritance code compile?

From:
"Paul" <pchrist<nospam>or@yahoo.co.uk>
Newsgroups:
comp.lang.c++
Date:
Mon, 2 Jan 2012 23:56:44 -0000
Message-ID:
<jdtg8d$4gq$1@adenine.netfront.net>
"Chris Stankevitz" <chrisstankevitz@gmail.com> wrote in message
news:d86e4d32-6781-4cf9-a85a-b806c4325764@r5g2000yqc.googlegroups.com...
On Jan 2, 1:36 pm, Paavo Helde <myfirstn...@osa.pri.ee> wrote:

You could try to make this 'public virtual Observer'.


Thank you, yes I overlooked this. Although this does not help the
compile problem.

That said, I'm not at all convinced that virtual inheritance is the right
approach here.


Me too -- if it doesn't compile, it probably is not the correct
approach!

How would you go about accomplishing this with C++, if it is possible:
- Create an abstract base class "Shape" that must be an "Observer"
- Create an class "Square" that is a "Shape" and uses "ObserverImp"
to implement the "Observer" behavior.


I don't see the problem here , maybe I am missing something.....

<code>
class observer{
public:
virtual void Notify()=0;
};

class observerImp:public observer{
public:
 virtual void Notify(){;}
};

class Shape:public observerImp{};
class Square: public Shape{ };

int main(){
 Shape* shp = new Square;
 shp->Notify();
  return 0;
}
</code>

Do you really need Shape to be abstract?

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