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From: jpd00964@uxa.cso.uiuc.edu
Newsgroups: comp.sys.mac.programmer
Subject: Re: Object Oriented C for the Mac
Message-ID: <227700016@uxa.cso.uiuc.edu>
Date: 24 Jul 89 04:50:00 GMT
References: <44053@tiger.oxy.edu>
Lines: 29
Nf-ID: #R:tiger.oxy.edu:44053:uxa.cso.uiuc.edu:227700016:000:1316
Nf-From: uxa.cso.uiuc.edu!jpd00964    Jul 23 23:50:00 1989


> what are the primary differences between
> object-oriented C and normal, run-of-the-mill C?

Object oriented C can be one of two things.
1> objective C, which is a preprocessor, therefore effectively run-of-the-mill
C with some standard routines to do object oriented programming.
2>  C++ which is an extension to c and therefore not normal C.

Object oriented programming is a method of storing routines in "objects" with 
their variables.  This allows easy portability.  I can in a given object,
define my variables to be any name since only these routines can affect the
variables.  The methods (functions by a different name) can be accessed by 
any other object.  So if you have a pointer to your object, and a routine
offset table, then can always indirectly get any variable.

The advantages:
All objects can be made interchangable.  For example.  If I have a cup object, 
that keeps track of the weight of all objects in it.  As I add a new object, 
it just needs a method called getWeight.  The cup will call getWeight and
my new object will return the correct weight.  The cup does not have to
concern itself with how a pen and another cup differ, the same called method
will concern itself. 

I have a better idea, read Object oriented programming by Cox.  It's a very
good book

Michael Rutman
Softmed