天天向上

   1: interface IWeapon

   2: {

   3:     void Use();

   4: }

   1: class Sword : IWeapon

   2: {

   3:     public void Use()

   4:     {

   5:         Console.WriteLine("Sword");

   6:     }

   7: }

   1: class Axe:IWeapon

   2: {

   3:     public void Use()

   4:     {

   5:         Console.WriteLine("Axe");

   6:     }

   7: }

   1: class Club:IWeapon

   2: {

   3:     public void Use()

   4:     {

   5:         Console.WriteLine("Club");

   6:     }

   7: }

   1: class Character

   2: {

   3:     IWeapon weapon;

   4:     public void SetWeapon(IWeapon weapon)

   5:     {

   6:         this.weapon = weapon; 

   7:     }

   8:     public void Attack()

   9:     {

  10:         weapon.Use();

  11:     }

  12: }

   1: class Null : IWeapon

   2:  {

   3:      public void Use()

   4:      {

   5:          Console.WriteLine("Null Object");

   6:      }

   7:  }

   1: class Null : IWeapon

   2: {

   3:     public void Use()

   4:     {

   5:         Console.WriteLine("Null Object");

   6:     }

   7: }

   1: class Program

   2: {

   3:     static void Main(string[] args)

   4:     {

   5:         IWeapon weapon = null;

   6:         Character ryan = new Character();

   7:  

   8:         while (true)

   9:         {

  10:             Console.WriteLine("Choose a weapon for ryan: 1.Sword 2. Axe 3. Club");

  11:             string input = Console.ReadLine();

  12:             switch(input)

  13:             {

  14:                 case "1":

  15:                     weapon = new Sword(); 

  16:                     break;

  17:                 case "2":

  18:                     weapon = new Axe();

  19:                     break;

  20:                 case "3":

  21:                     weapon = new Club();

  22:                     break;

  23:                 default:

  24:                     weapon = new Null();

  25:                     break;

  26:             }

  27:             ryan.SetWeapon(weapon);

  28:             ryan.Attack();

  29:         }

  30:     }

  31: }