using System;

public class Program : IVisitor

{

    public static void Main()

    {

        var p=new Program();

        ICommonInterface[] children = new ICommonInterface[]{ new Child1(), new Child2(), new Child3() };

        foreach( var child in children)

            child.Host(p);

    }

    public void VisitedBy(Child1 c){ Console.WriteLine("Hello from Child1"); }

    public void VisitedBy(Child2 c){ Console.WriteLine("Hello from Child2"); }

    public void VisitedBy(Child3 c){ Console.WriteLine("Hello from Child3");}

}

​

public interface IVisitor

{

    public void VisitedBy(Child1 c);

    public void VisitedBy(Child2 c);

    public void VisitedBy(Child3 c);

}

​

public interface IHost

{

    void Host(IVisitor visitor);

}

​

public interface ICommonInterface : IHost

{

}

​

public class Child1:ICommonInterface

{

    public void Host(IVisitor visitor)

    {

        visitor.VisitedBy(this);

    }

}

​

public class Child2:ICommonInterface

{

    public void Host(IVisitor visitor)

    {

        visitor.VisitedBy(this);

    }

}

​

public class Child3:ICommonInterface

{

    public void Host(IVisitor visitor)

    {

        visitor.VisitedBy(this);

    }

}

​