游戏管理器与单例模式

示例

public class GameManager
{
    private static GameManager instance;
    private GameManager() { }
    public static GameManager Instance
    {
        get
        {
            if (instance == null)
            {
                instance = new GameManager();
            }
            return instance;
        }
    }
    private int bulletNumber;

	public int ConsumeBullet(int capacity)
	{
		if(bulletNumber >= capacity)
		{
			bulletNumber -= capacity;
			return capacity;
		}
		int tem = bulletNumber;
		bulletNumber = 0;
		return tem;
	}
}