面向对象作业

1设计一个倒计时器

class Clock(object):
    def __init__(self, h, m, s):
        self.hour = h
        self.minute = m
        self.second = s

    def run_clock(self):
        if self.second == 0:
            self.minute -= 1
            self.second =60
        if self.minute < 0 :
            if self.hour != 0:
                self.hour -= 1
                self.minute = 59
        self.second -= 1

    def __str__(self):
        # 显示时间
        if self.hour == 0 and self.minute == 0 and self.second == 0:
            return 0
        return '%02d:%02d:%02d'%(self.hour,self.minute,self.second)


def main():
    clock = Clock(2, 0, 2)
    while True:
        time.sleep(1)
        if clock.__str__() == 0:
            print('时间到了')
            break
        print(clock)
        clock.run_clock()

if __name__ == '__main__':
    main()