using System;

public class Program

{

    public static void Main()

    {

        var cow = new Animal("cow","moo");

        var duck = new Animal("duck","quack");

        var pig = new Animal("pig","oink");

        var dog = new Animal("dog","woof");

        cow.Sing();

        duck.Sing();

        pig.Sing();

        dog.Sing();

    }

​

    public class Animal

    {

        private string _name;

        private string _sound;

        public Animal(string name, string sound)

        {

            _name = name;

            _sound = sound;

        }

        public void Sing()

        {

            var song = $@"Old MACDONALD had a farm

                        E-I-E-I-O

                        And on his farm he had a {_name}

                        E-I-E-I-O

                        With a {_sound} {_sound} here

                        And a {_sound} {_sound} there

                        Here a {_sound}, there a {_sound}

                        Everywhere a {_sound} {_sound}

                        Old MacDonald had a farm

                        E-I-E-I-O";

            Console.WriteLine(song);

            Console.WriteLine();

        }

    }

}