1.声明⼀个电脑类: 属性:品牌、颜⾊、内存⼤小 方法:打游戏、写代码、看视频
a.创建电脑类的对象，然后通过对象点的方式获取、修改、添加和删除它的属性
b.通过attr相关⽅方法去获取、修改、添加和删除它的属性

class Pc:
    def __init__(self, brand='apple', color='black', ram='4g'):
        self.brand = brand
        self.color = color
        self.ram = ram

    def play_game(self):
        return '打游戏'

    def coding(self):
        return '写代码'

    def watch_video(self):
        return '看视频'
        
        
# a
pc1 = Pc('MicroSoft', 'Silver', '8G')
# 查
pc1.brand
# 改
pc1.brand = 'Apple'
# 增
pc1.os = 'win10'
# 删
del pc1.os
# b
# 查
getattr(pc1, 'brand')
# 改
setattr(pc1, 'brand', 'Apple')
# 增
setattr(pc1, 'os', 'win10')
# 删
delattr(pc1, 'os')

2.声明⼀个人的类和狗的类:
狗的属性:名字、颜⾊色、年年龄
狗的⽅方法:叫唤
人的属性:名字、年年龄、狗
人的⽅方法:遛狗
a.创建⼈人的对象⼩小明，让他拥有⼀一条狗⼤大⻩黄，然后让⼩小明去遛⼤大⻩黄

class Pet:
    def __init__(self, pet_name='dog', color='yellow', age='2'):
        self.pet_name = pet_name
        self.color = color
        self.age = age

    def bark(self):
        print('%s开始了叫唤' % self.pet_name)


class Owner:
    def __init__(self, name='jack', age=18, pet=None):
        self.name = name
        self.age = age
        self.pet = pet

    def walk_the_dog(self):
        if not self.pet:
            print('你没有狗!遛自己!!')
        else:
            print('%s牵着%s在散步' % (self.name, self.pet.pet_name))


d1 = Pet('大黄', '黄', '2')
p1 = Owner('小明', 18, d1)
p1.walk_the_dog()

3.声明⼀一个圆类，自己确定有哪些属性和方法

class Circle:
    pie = 3.1415926535897

    def __init__(self, radius=1):
        self.radius = radius

    def square(self):
        return Circle.pie * (self.radius ** 2)

    def perimeter(self):
        return Circle.pie * self.radius * 2

4.创建⼀一个学⽣生类:
属性:姓名，年龄，学号
方法:答到，展示学⽣生信息
创建⼀一个班级类:
属性:学⽣生，班级名
方法:添加学⽣生，删除学生，点名, 求班上学生的平均年龄

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

    def response(self):
        print('%s,到!' % self.name)

    def show_stu_info(self):
        print('姓名:%s,年龄:%d,学号:%s' % (self.name, self.age, self.stu_id))


class Class:
    def __init__(self, class_name):
        self.class_name = class_name
        self.students = []

        def func1():
            num = 1
            while True:
                yield 'stu'+str(num)
                num += 1
        self.create_id = func1()

    def add_student(self):
        name = input('学生姓名:')
        age = int(input('学生年龄:'))
        stu_id = next(self.create_id)
        stu = Student(name, age, stu_id)
        self.students.append(stu)

    def del_student(self):
        del_name = input('请输入要删除的学生的姓名:')
        flag = False
        for stu in self.students[:]:
            if stu.name == del_name:
                flag = True
                stu.show()
                value = input('是否删除(y/n):')
                if value == 'y':
                    self.students.remove(stu)
        if not flag:
            print('没有该学生!')

    def call_name(self):
        pass

    def show_all_students(self):
        print('===========%s===========' % self.class_name)
        for stu in self.students:
            stu.show_stu_info()