模拟qq游戏实现单机版的21点游戏，比较不错的，很有意思-21

21点游戏，玩家和电脑玩，谁的牌数和加起来大并且不超过21点就赢-21-point game, the player and the computer to play, who is large and the number of cards and add up to no more than 21-point win