About Python3 — 2

class Animal(object):
    def eat(self):
        print("动物会吃")


class Cat(Animal):
    def eat(self):
        print("猫吃鱼")


class Dog(Animal):
    def eat(self):
        print("狗吃骨头")


class Person(object):
    def eat(self):
        print("人吃五谷杂粮")


def func(creature):
    creature.eat()

class A(object):
    pass


class B(object):
    pass


class C(A, B):
    def __init__(self, name, age):
        self.name = name
        self.age = age


x = C('gdc', 20)
if __name__ == '__main__':
    # __dict__ 显示 实例 和 方法 的情况
    print(x.__dict__)
    print(C.__dict__)
    print('_____________________________')

    # 输出对象所属的类
    print(x.__class__)
    print(C.__bases__)  # return the tuple of the parent class
    print(C.__base__)  # return the basic parent class
    print(C.__mro__)
    print(A.__subclasses__())  # return the list of the subclasses
    print('_____________________________')

class Student:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    # override the __add__() can add two classes
    def __add__(self, other):
        return self.age + other.age

    def __len__(self):
        return len(self.name)


stu1 = Student('1', 20)
stu2 = Student('gdc', 20)

if __name__ == '__main__':
    print(stu1 + stu2)
    print('__________________________')
    print(stu2.__len__())