class Student():

    def __init__(self, name, age):

        # 构造函数

        # 初始化变量的属性

        self.name = name

        self.age = age

        self.__score = 0  # 这里是私有变量

    # def __marking(self, score):  # 这里使用__是方法变成私有方法

    def marking(self, score):  # 这里使用__是方法变成私有方法

        if 0 <= score <= 100:

            self.__score = score

        else:

            self.__score = 0

        print(self.__score)

stu = Student("王", 19)

# stu.marking(10)  # 这里调用出错，因为是私有方法

stu.marking(10)

# print(stu.score)   # 这里调用出错，因为是私有变量

stu.__score = 19  # 不报错，原因从下面的代码中，多增加了一个变量'__score': 19

print(stu.__dict__)  # {'name': '王', 'age': 19, '_Student__score': 10, '__score': 19}

print(stu._Student__score)  # python 将私有变量变成_Student__score形式，可以访问

class B():

    sums = 0

    def __init__(self, name, age):

        self.name = name

        self.age = age

    def get_name(self):

        print(self.name)

class A(B):

    def do_homework(self):

        print("hello!")

stu = A("王", 20)

print(stu.sums)

print(A.sums)

print(B.sums)

print(stu.name)

------------------------------分割线----------------------------------------

class B():

    sums = 0

    def __init__(self, name, age):

        self.name = name

        self.age = age

    def get_name(self):

        print(self.name)

class A(B):

    def __init__(self, school, name, age):

        self.school = school

        # B.__init__(self, name, age)  # 这里要传入self，否则报错（形参和实参对应）

        super(A, self).__init__(name, age)  # 使用super调用父类的方法，常用

    def do_homework(self):

        print("hello!")

stu = A("北大", "王", 20)

print(stu.sums)

print(A.sums)

print(B.sums)

print(stu.name)

print(stu.school)