Re: Instance methods VS. Class methods
Re: Instance methods VS. Class methods
- Subject: Re: Instance methods VS. Class methods
- From: Jeff LaMarche <email@hidden>
- Date: Sat, 24 Nov 2001 09:13:12 -0800
Well, class methods are ones that you can use regardless of whether
you've instantiated any objects of that class or not. The most common
use of class objects is a "generator" class, such as [NSImage
imageWithContentsOfFile], which returns an NSImage object. You use these
generator classes in lieu of the alloc/init calls. Class methods are
also used much the same way that a public static method is in Java.
Class methods cannot access any instance variables (just like static
methods) and must be self-contained. This makes them well-suited to
utility methods or methods related to a class that other objects might
want to use.
Instance methods are just like methods in Java and member functions in
C++ - you have full access ot the instance variables, but they only
operate on the instance they belong to and there must be an instance of
the object in order to access them.
I have a feeling someone else will come along with a more elegant
explanation, but that should give you a basic understanding of the
difference.
Jeff
On Friday, November 23, 2001, at 08:19 PM, Matt Ronge wrote:
Hi,
I've read through Apple's docs, read through Learning Cocoa, and I have
searched all over the web. Yet none of them have shed light on the
difference between instance methods and class methods?
Can someone give examples of why you would use one over the other? Is
there
something comparable in C++ to them? Is one of them just a private
method
identifer for use internally by the class?
Sorry for the newbie question,
Forward thanks for any help,
--
Matt Ronge
President
Monkeybread Software
http://www.monkeybreadsoftware.com
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