From: "Wolfgang Nádasi-Donner" <wonado@...>
Date: 2005-03-15T22:58:22+09:00
Subject: Re: [newby] class variables and class instance variable?

--
Wolfgang N�dasi-Donner
wonado@donnerweb.de
"Florian Gross" <flgr@ccan.de> schrieb im Newsbeitrag
news:39itt7F5tgm5bU1@individual.net...
> Wolfgang N�dasi-Donner wrote:
>
> > The class variable ("@@") belongs to the class object, while the
instance
> > variable (@) belongs to the instanciated object. A short example. May be
you
> > want to count how many objects are created based on a class. If you want
to
> > avoid global variables ($), which is a very good decision, you can use
class
> > variables. Using instance variables will not work.
>
> It will. Note that the poster said "class instance variable" which is

*****************************************************
Ooops - need new glasses, I believe ;-) - Forget my example, please.
I often switch between Ruby an C#. This results in some confusion.
*****************************************************

> the instance variable of a Class. Classes are instances of Class and
> Class inherits from Module which inherits from Object so classes are
> objects as well:
>
> class Foo
>    @counter = 0
>    class << self
>      attr_accessor :counter
>    end
>
>    def initialize()
>      self.class.counter += 1
>    end
> end
>
> Foo.counter # => 0
> 5.times { Foo.new }
> Foo.counter # => 5