练习22——初识面向对象

1.人狗大战

class Person:
    def __init__(self, name, blood, aggr, sex):
        self.name = name
        self.blood = blood
        self.aggr = aggr
        self.sex = sex

    def attack(self, dog):
        dog.blood -= self.aggr

class Dog:
    def __init__(self, name, blood, aggr, kind):
        self.name = name
        self.blood = blood
        self.aggr = aggr
        self.kind = kind

    def bite(self, person):
        person.blood -= self.aggr

jin = Dog('金老板', 100, 20, 'teddy')
alex = Person('alex', 200, 10, '未知')
alex.attack(jin)
jin.bite(alex)
print(jin.blood)
print(alex.blood)

2.圆周长面积、正方形周长面积

circle 属性 半径 ，两个方法：求周长和面积
from math import pi
class circle:
    def __init__(self, r):
        self.r = r

    def area(self):
        print('面积是：{:.2f}'.format(pi * self.r**2))
    def perimeter(self):
        print('周长是：{:.2f}'.format(pi * self.r * 2))
c = circle(5)
c.area()
c.perimeter()

#正方形的面积和周长
class cube:
    def __init__(self, l):
        self.l = l

    def area(self):
        print('面积：{}'.format(self.l**2))

    def perimeter(self):
        print('周长：{}'.format(self.l*4))

cu1 = cube(5)
cu1.area()
cu1.perimeter()