贪吃蛇：

1.程序开始时，贪吃蛇便开始爬行，方向默认朝下

2.当按下方向按键上下左右时，贪吃蛇便根据按下的键值改变当前的运行方向

3.当贪吃蛇越过边界，或者蛇头碰到自己的蛇身时，宣布死亡，重新生成一条贪吃蛇

4.当贪吃蛇吃掉一个食物，就自动加长一个节点



食物：

1.程序开始时，屏幕内自动生成一个食物

2.当贪吃蛇死亡时，重新生成一个食物

3.生成的食物不能与贪吃蛇的坐标重合-Snake: 1. When the program starts, the snake began to crawl, when the downward direction of the default 2. When you press the up and down direction keys, Snake will be based on the keys pressed to change the current direction of travel 3. When When Snake crossed the border, or snakeheads met his snake, declared dead, regenerate 4. When a Snake Snake eats a food, it is automatically extended one node food: 1. When the program starts, the screen automatically generated within a food 2. When Snake death, regenerate a food 3. Generate the food can not coincide with the coordinates of the Snake