void move()
	{
		if(isLive)
		{
			sx+=lengthX;
			sy+=lengthY;

			if(isOutOfWindow()||isHitTank()||isHitWall())
			{
				this.dead();
			}
			if((int)Math.hypot(sx-oldx,sy-oldy)>MOVERANGE)  //ƶһը
			{
				//this.isBomb=true;
				this.dead();
			}
		}
	}