Re: Abstraction encapsulation & interfaces

From: Alwyn (dt015a1979_at_mac.com.invalid)
Date: 10/15/04


Date: Fri, 15 Oct 2004 11:50:18 +0100

In article <2t9nl1F1sh7jkU1@uni-berlin.de>, Val \
<chrisval@bigpond.com.au> wrote:
>
> | How exactly does that differ from what I said?
>
> Well, you asked this question:
> "| Doesn't abstracting an implementation mean the same as
> | providing an interface for it?"
>
> AFAIUI, you only have an interface, if you have encapsulation,
> and you only have encapsulation, if you have private or possibly
> protected data

I think we are splitting hairs now.

> - Otherwise you just have an public 'C' structure
> that offers nothing of real value.

You can implement abstract data types in C too, arguably just as well
as in C++. Opaque types are also possible, where the implementation
data are completely hidden; you might even find the following page
interesting:
<http://developer.apple.com/documentation/CoreFoundation/Conceptual/CFDe
signConcepts/Concepts/OpaqueTypes.html>

Alwyn