7-6 sdut-oop-9 计算长方形的周长和面积（类和对象） --python

知识点：
python创建多个构造方法

1. 使用classmethod
2. 将init的参数设为可变类型，在init语句中判断

class Rect:
    __length = 0
    __width = 0

    def __init__(self, l, w):
        self.__length = l
        self.__width = w

    @classmethod
    def initsec(self, l):
        return self(l, l)

    def leng(self):
        return self.__length

    def widt(self):
        return self.__width

    def e(self):
        return self.__width * self.__length

    def z(self):
        return 2 * (self.__width + self.__length)


while True:
    try:
        num = [int(x) for x in input().split()]
        if len(num) == 1:
            if num[0] <= 0:
                num[0] = 0
            t = Rect.initsec(num[0])

        else:
            if num[0] <= 0 or num[1] <= 0:
                num[0] = 0
                num[1] = 0
            t = Rect(num[0], num[1])

        print(t.leng(), t.widt(), t.z(), t.e())
    except:
        break