class Cat():
    """  类 """

    tag = '我是家猫'

    def __init__(self, name, age):
        self.name = name
        #  私有变量
        self.__age = age

    def set_age(self, age):
        self.__age = age
        # return self.__age

    def show_info(self):
       rest = '我叫:{0},今年{1}岁'.format(self.name, self.__age)
       print(rest)
       return rest

    def eat(self):
        """ 吃 """
        print("猫喜欢吃鱼")


    def catch(self):
        """  抓老鼠 """
        print("我能抓老鼠")


if __name__ == '__main__':
    # 实例化
    cat_black = Cat('小黑',2)
    cat_black.eat()
    cat_black.show_info()

    print('--------')
    # print(cat_black.name)  # 小黑
    # print(cat_black.age)
    #  私有变量无法访问
    # print(cat_black.__age)
    cat_black.name  = '小白'
    cat_black.show_info()  #我叫:小白,今年2岁

    print('--------')
    # 设置年龄
    # cat_black.set_age(7)
    # cat_black.show_info()  我叫:小白,今年7岁

    print(Cat.tag)
    print(cat_black.tag)

    print('--------')
    # 判断是否是类的实例
    print(isinstance(cat_black, Cat))  #True