Python-组合

源代码如下：

class Turtle:
    def __init__(self, x):
        self.num = x
class Fish:
    def __init__(self, x):
        self.num = x
class Pool:
    def __init__(self, x, y):
        self.turtle = Turtle(x)
        self.fish = Fish(y)

    def print_num(self):
        print('水池里总共有%d只乌龟，%d只鱼'%(self.turtle.num, self.fish.num))
pool = Pool(1, 10)
pool.print_num()

运行结果如下：

水池里总共有1只乌龟，10只鱼