23种设计模式之策略模式（strategy）

public class Hand  
{  
    public const int HANDVALUE_GUU = 0;//石头  
    public const int HANDVALUE_CHO = 1;//剪刀  
    public const int HANDVALUE_PAA = 2;//布  
  
    private int handvalue;  
    private Hand(int handvalue)  
    {  
        this.handvalue = handvalue;  
    }  
  
    public static Hand[] hands =   
    {   
        new Hand(HANDVALUE_GUU),   
        new Hand(HANDVALUE_CHO),   
        new Hand(HANDVALUE_PAA)   
    };  
  
    /// <summary>  
    /// 从值获得对象实例  
     /// </summary>  
    /// <param name="handvalue"></param>  
    /// <returns></returns>  
    public static Hand GetHand(int handvalue)  
    {  
        return hands[handvalue];  
    }  
}  

public interface Strategy  
{  
    Hand NextHand();  
} 

public class WinningStrategy : Strategy  
{  
    private bool won = false;  
    private Hand prevHand;  
    private Random random = new Random();  
  
    public Hand NextHand()  
    {  
        if (!won)  
        {  
            prevHand = Hand.GetHand(random.Next(3));  
        }  
        Console.WriteLine("调用了WinningStrategy策略");  
        return prevHand;  
    }  
}  

public class ProbStrategy : Strategy  
{  
    public Hand NextHand()  
    {  
        int handvalue = 0;  
        //省略具体实现  
  
        Console.WriteLine("调用了ProbStrategy策略");  
        return Hand.GetHand(handvalue);  
    }  
}  

public class Player  
{  
    private string name;  
    private Strategy strategy;  
    public Player(string name, Strategy strategy)  
    {  
        this.name = name;  
        this.strategy = strategy;  
    }  
  
    /// <summary>  
    /// 向战略请示手势  
    /// </summary>  
    /// <returns></returns>  
    public Hand NextHand()  
    {  
        return strategy.NextHand();  
    }  
}  

class Program  
{  
    static void Main(string[] args)  
    {  
       //策略模式  
        while (true)  
        {  
            Console.WriteLine("/r/n请选择：1、WinningStrategy策略游戏；2、ProbStrategy策略游戏...");  
            string line = Console.ReadLine();  
            if (line.Equals("1"))  
            {  
                Strategy.Strategy strategy = new WinningStrategy();  
                Player player = new Player("abc", strategy);  
                player.NextHand();  
            }  
            else if (line.Equals("2"))  
            {  
                Strategy.Strategy strategy = new ProbStrategy();  
                Player player = new Player("abc", strategy);  
                player.NextHand();  
            }  
        }  
    }  
}