Program.cs

using System;

namespace VisitorPattern
{
// Visitee
interface IAnimal
{
  void Accept(IAnimalOperation operation);
}

// Visitor
interface IAnimalOperation
{
  void VisitMonkey(Monkey monkey);
  void VisitLion(Lion lion);
  void VisitDolphin(Dolphin dolphin);
}

class Monkey : IAnimal
{
  public void Shout()
  {
    Console.WriteLine("Oooh o aa aa!");
  }

  public void Accept(IAnimalOperation operation)
  {
      operation.VisitMonkey(this);
  }
}

class Lion : IAnimal
{
  public void Roar()
  {
    Console.WriteLine("Roaar!");
  }

  public void Accept(IAnimalOperation operation)
  {
      operation.VisitLion(this);
  }
}

class Dolphin : IAnimal
{
  public void Speak()
  {
    Console.WriteLine("Tuut tittu tuutt!");
  }

  public void Accept(IAnimalOperation operation)
  {
      operation.VisitDolphin(this);
  }
}

class Speak : IAnimalOperation
{
  public void VisitDolphin(Dolphin dolphin)
  {
    dolphin.Speak();
  }

  public void VisitLion(Lion lion)
  {
    lion.Roar();
  }

  public void VisitMonkey(Monkey monkey)
  {
    monkey.Shout();
  }
}

class Jump : IAnimalOperation
{
  public void VisitDolphin(Dolphin dolphin)
  {
      Console.WriteLine("Walked on water a little and disappeared!");
    }

  public void VisitLion(Lion lion)
  {
    Console.WriteLine("Jumped 7 feet! Back on the ground!");
  }

  public void VisitMonkey(Monkey monkey)
  {
      Console.WriteLine("Jumped 20 feet high! on to the tree!");
    }
}


  class Program
  {
    static void Main(string[] args)
    {
var monkey = new Monkey();
var lion = new Lion();
var dolphin = new Dolphin();

var speak = new Speak();

monkey.Accept(speak);    // Ooh oo aa aa!    
lion.Accept(speak);      // Roaaar!
dolphin.Accept(speak);   // Tuut tutt tuutt!

var jump = new Jump();

monkey.Accept(speak);   // Ooh oo aa aa!
monkey.Accept(jump);    // Jumped 20 feet high! on to the tree!

lion.Accept(speak);     // Roaaar!
lion.Accept(jump);      // Jumped 7 feet! Back on the ground!

dolphin.Accept(speak);  // Tuut tutt tuutt!
dolphin.Accept(jump);   // Walked on water a little and disappeared

      Console.ReadLine();
    }
  }
}