1.游戏要有图形用户界面，界面能够反映游戏所有的细节。
2.界面中要有坦克，墙，树林，河流。
3.界面中要有一个“家”,“家”被攻击中则输了游戏。
4.坦克分两种，敌方和我方。
5.墙也分为两种，可以穿透的普通墙，不可以穿透的铁墙。
6.树和河流均只有一种，树林坦克可以通过。
7.坦克可以发射子弹，敌我方的子弹属性一样。
8.我方子弹可以杀死敌方坦克，敌方子弹也可以杀死我方坦克，但需要多枪子弹才可以杀死。
9.敌方之间不可以杀死对方。(Implement a java version of the tank war game
[functional hints]
1. games have a graphical user interface, and the interface can reflect all the details of the game.
There are tanks, walls, woods, and rivers in the 2. interface.
There is a "home" in the 3. interface, and the "home" is attacked by the game.
4. tanks are divided into two types, the enemy and us.
The 5. walls are also divided into two kinds, the ordinary walls that can penetrate, the iron walls that can not be penetrated.
There is only one of the 6. trees and rivers, and the forest tanks can pass.
7. tanks can launch bullets, the enemy and our side of the same bullet properties.
8. our bullets can kill the enemy tanks, and the enemy bullets can kill our tanks, but they need multiple guns to kill them.
9. enemies can't kill each other.)