'''
类方法
@classmethod注解在方法上标识
'''

from time import time, localtime, sleep

class Clock(object):
    '''数字时钟'''

    def __init__(self, hour=0, minute=0, second=0):
        self._hour = hour
        self._minute = minute
        self._second = second

    '''类方法'''
    @classmethod
    def now(cls):
        ctime = localtime(time())
        return cls(ctime.tm_hour, ctime.tm_min, ctime.tm_sec)
    
    def run(self):
        '''走字'''
        self._second += 1
        if self._second == 60:
            self._second = 0
            self._minute += 1
            if self._minute == 60:
                self._minute = 0
                self._hour += 1
                if self._hour == 24:
                    self._hour = 0

    def show(self):
        '''显示时间'''
        return '%02d:%02d:%02d' % (self._hour, self._minute, self._second)

def main():
    # 通过类方法创建对象并获取系统时间
    clock = Clock.now()
    while True:
        # 打印当前时间
        print(clock.show())
        sleep(1)
        clock.run()

if  __name__ == '__main__':
    main()