定义一个狗类和一个人类：

狗拥有属性：姓名、性别和品种 拥有方法：叫唤

人类拥有属性：姓名、年龄、狗 拥有方法：遛狗

class Dog:
    def __init__(self, name, gender, variety):
        self.name = name
        self.gender = gender
        self.variety = variety
    def howl(self):
        print(f'{self.name}在叫唤')

d = Dog('旺财', '公', '柯基')
d.howl()

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age
    def stroll(self, dog):
        print(f'{self.name}遛{dog.name}')


p = Person('隔壁老王', '18')
p.stroll(Dog('旺财', '公', '柯基'))

定义一个矩形类，拥有属性：长、宽 拥有方法：求周长、求面积

class Rectangle:
    def __init__(self, length, width):
        self.length = length
        self.width = width
    def Perimeter(self):
        return self.width * 2 + self.length * 2
    def Area(self):
        return self.width * self.length
r = Rectangle(10, 5)
print(f'周长：{r.Perimeter()}, 面积：{r.Area()}')

定义一个二维点类，拥有属性：x坐标、y坐标 拥有方法：求当前点到另外一个点的距离

class Two:
    def __init__(self, x, y):
        self.x = x
        self.y = y
    def Get_distance(self, point):
        g = ((self.x - point.x) ** 2 + (self.y - point.y) ** 2) ** 1/2
        return g
t = Two(2, 3)
print(f'两点间的距离为{t.Get_distance(Two(3, 7))}')

定义一个圆类，拥有属性：半径、圆心 拥有方法：求圆的周长和面积、判断当前圆和另一个圆是否外切

pi = 3.1415926
class Circle:
    def __init__(self, r, x, y):
        self.r = r
        self.x = x
        self.y = y

    def Perimeter(self):
        return 2 * pi * self.r

    def Area(self):
        return pi * self.r ** 2

    def Judge(self, point):
        g = ((self.x - point.x) ** 2 + (self.y - point.y) ** 2) ** 1 / 2
        gg = self.r + point.r
        if g == gg:
            return 'yes'
        else:
            return 'no'
t = Circle(3, 2, 3)
print(f'是否外切：{t.Judge(Circle(4, 3, 7))}')

定义一个线段类，拥有属性：起点和终点， 拥有方法：获取线段的长度

class Segment:
    def __init__(self, begin, end):
        self.begin = begin
        self.end = end
    def Get_length(self):
        return self.end - self.begin
s = Segment(5, 10)
s.Get_length()
print(f'该线段长度为{s.Get_length()}')