using System;

​

public delegate void someDel(string str);

​

public class SomeClass

{   

    public void Print(string a, string b, someDel callback){

        Console.WriteLine(a + b);

        callback(a);

    }

    public void str_(string str){

        str = str + str;

    }

    public void str_1(string str){

        Console.WriteLine("delegate " + str);

    }

}

public class Program

{

    //public delegate void someDel(string str);

    public static void Main()

    {

        SomeClass someClass = new SomeClass();

        someDel del = someClass.str_1;

        someClass.Print("hi", " there", del);

        //Console.WriteLine("Hello World");

    }

}