'''
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()