From: Yochen Gutmann <yoche2001@...>
Date: 2006-08-06T03:51:44+09:00
Subject: Inheritance with class-variables

Hi,

I am quite new into ruby and stumbled over some strange (at least to me) 
behavior.
Have a look and guess what the output of this code might be:

class Animal
  @@temperature = 0

  def info_temperature
    puts "My body temperature is "+@@temperature.to_s+" degree"
  end
end

class Spider < Animal
  @@temperature = 20
end

class Horse < Animal
  @@temperature = 38
end

batty = Spider.new
fury = Horse.new

batty.info_temperature
fury.info_temperature

Well, for myself, I'd expected that the result were "My body temperature 
is 20 degree" and "My body temperature is 38 degree".

But surprise, surprise, both animals tell me that they have 38 degree! 
The next strange thing is that this effect seems to depend on the order 
of the class-definition.

How does this happen? And Why ;-)

Thanx,
Yochen

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