'''
@Author: your name
@Date: 2020-07-19 10:29:31
@LastEditTime: 2020-07-19 10:51:19
@LastEditors: Please set LastEditors
@Description: In User Settings Edit
@FilePath: \vscode_py\day13.py
'''
import math
# Question 47
# 写一个类，计算圆的面积
class Circle():
    def __init__(self,r):
        self.r = r
        print("Circle constructor")
    def area(self):
        self.area=(self.r)**2*math.pi

# Question 48
# 矩形类
class Rect():
    def __init__(self,l,w):
        self.l = l
        self.w = w
        print("Rect constructor")
    def area(self):
        self.area=(self.l*self.w)
        print("Rect area:{}".format(self.area))


# Question 49
# 定义一个类Shape，其子类为Square，计算面积
class Shape():
    def __init__(self):
        pass    
    def area(self):
        return 0
class Square(Shape):
    def __init__(self,length=0):
        Shape.__init__(self)   # 父类初始化
        self.length = length
        # self.area=0
        print("Square constructor")
    def area(self):
        self.area=(self.length)**2
        print("Square:{}".format(self.area))
    

# Question 50
# Please raise a RuntimeError exception.
# Use raise() to raise an exception.
def Q50():
    raise RuntimeError("something wrong")





if __name__ == "__main__":
    # c=Circle(10)
    # c.area()
    # print(c.area)



    # r=Rect(10,5)
    # r.area()



    # s=Square(3)
    # s.area()
    
    # f=Shape()
    # print(f.area())

    # s1=Square()
    # s1.area()

    Q50()