# coding:utf-8

 class Animal(object):

     def __init__(self):

         self._name = None

         self._f = None

     def eat(self):

         print("%s吃%s" % (self._name, self._f().food()))

 class Dog(Animal):

     def __init__(self):

         Animal.__init__(self)

         self._f = DogFood

         self._name = "狗"

 class DogFood():

     def food(self):

         return "狗粮"

 class Cat(Animal):

     def __init__(self):

         Animal.__init__(self)

         self._name = "猫"

         self._f = CatFood

 class CatFood():

     def food(self):

         return "猫粮"

 dog = Dog()

 dog.eat()

 cat = Cat()

 cat.eat()

 # coding:utf-8

 class CatFood():

     def food(self, food_name):

         self.food_name = food_name

 cf = CatFood

 cf1 = CatFood()

 cf1.food("鱼")

 cf2 = CatFood()

 cf2.food("粥")

 print(cf1.food_name)

 print(cf2.food_name)

 # coding:utf-8

 class CatFood():

     def food(self, food_name):

         self.food_name = food_name

 cf = CatFood

 cf1 = CatFood()

 cf1.food("鱼")

 cf2 = CatFood()

 cf2.food("粥")

 print(CatFood)

 print(cf)

 print(cf1)