说明：  这可是我昨天晚上的程序啊，对程序的注释比较到位，很容易理解的，只是有一些小的偏差，请朋友们帮忙改进吧，
(this yesterday evening procedures ah, the program notes compared in place, it is easy to understand. only some minor deviations, friends help improve it, thank you)