protected Tank containsRelativeEnemyTank(Tank tank, int x, int y){
		
		if(tank.isPlayer()){
			for(Tank t: _enemyTanks){
				if(t.getX() == x && t.getY() == y)
					return t;
			}
		}else{
			for(Tank t: _playerTanks){
				if(t.getX() == x && t.getY() == y)
					return t;
			}
		}		
		return null;
	}