From: 7stud -- <dolgun@...>
Date: 2007-09-26T23:26:43+09:00
Subject: Re: difference between inheritance and mixin

> what is the use of mixin and what is the use of inheritance

1)
class FourLeggedAnimal
  def speed
    puts "I run fast."
  end
end

class Mammal
  def birth
    puts "My babies don't hatch from eggs."
  end
end

class Dog < FourLeggedAnimal
  def speak
    puts "Bark, bark."
  end
end

d = Dog.new
d.speak
d.speed
d.birth

--output:--
Bark, bark.
I run fast.
r6test.rb:21: undefined method `birth' for #<Dog:0x251ac> 
(NoMethodError)


2)
class FourLeggedAnimal
  def speed
    puts "I run fast."
  end
end

module Mammal
  def birth
    puts "My babies don't hatch from eggs."
  end
end

class Dog < FourLeggedAnimal
  include Mammal

  def speak
    puts "Bark, bark."
  end
end

d = Dog.new
d.speak
d.speed
d.birth

--ouput:--
Bark, bark.
I run fast.
My babies don't hatch from eggs.


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