实现贪吃蛇的有关功能，代码齐全

在该游戏中，玩家操纵一条贪吃的蛇在迷宫里行走，贪吃蛇按玩家所按的方向键折行，蛇头吃到各种食物(比如大力丸)后，会有各种反应(比如蛇身变长)，假如贪吃蛇碰上墙壁或者自身的话，就GameOver了(当然也可能是减去一条生命)。-Snake in the functional implementation, code complete in the game, players control a greedy snake walking in the maze, Snake by players off the line by the arrow keys, snakeheads eat a variety of foods (such as Dali Wan ), there will be a variety of responses (such as snake longer), if the Snake, then hit the wall or their own to GameOver (of course it may be less of a life.)