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