super()函数的作用

1.super()调用父类方法，并重写>>>>>>减少代码量(Square类实现) 
2.它允许您在子类中调用超类的方法。 这种情况的主要用例是扩展继承方法的功能。 (cube类实现)
3.控制MRO（方法解析顺序）的构建方式

class Rectangle(object):

def __init__(self,length,width):
        self.length=length
        self.width=width

    def area(self):
        return self.length*self.width

    def Perimeter(self):
        return 2*self.length+2*self.width

# class Square(object):
#     def __init__(self,length):
#         self.length=length

#     def area(self):
#         return self.length*self.length

#     def Perimeter(self):
#         return 4*self.length
class Square(Rectangle):
    def __init__(self,length):
        super().__init__(length,length)

class Cube(Square):
    #表面积
    def surface_area(self):
        face_area=super().area()
        return face_area*6
    def volume(self):
        face_area=super().area()
        return self.length*face_area

def main():
    rectangle=Rectangle(2,4)
    print(rectangle.area(),rectangle.Perimeter())
    square=Square(4)
    print(square.area(),square.Perimeter())
    cube=Cube(4)
    print(cube.area(),cube.Perimeter(),cube.surface_area(),cube.volume())
if __name__ == '__main__':
    main()