Understanding Properties Concept in C#

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

namespace Apps

{

    class PropertiesTest

    {

        private string title = "Hi";

        public string Title

        {

            get

            {

                return title;

            }

            set

            {

                title = value;

            }

        }

        public int duration { get; set; }

        public int fees { get; set; }

        private string[] topics = new string[5];

        public string this[int index]           // Implementing Indexer

        {

            get

            {

                return topics[index];

            }

            set

            {

                topics[index] = value;

            }

        }

        public void print()

        {

            Console.WriteLine(title);

        }

        public PropertiesTest(string title, int duration, int fees)

        {

            this.title = title;

            this.duration = duration;

            this.fees = fees;

            print();

        }

    }

    class UnderstandingPropertiesConcept

    {

        public static void Main()

        {

            PropertiesTest pt1 = new PropertiesTest("MS.Net", 52, 6000);

            pt1.Title = "Hello";

            Console.WriteLine(pt1.Title);

            PropertiesTest pt = new PropertiesTest("MS.Net", 52, 6000);

            Console.WriteLine(pt.Title);

            pt[0] = "Indexer Concept";

            pt[1] = "Indexer Concept";

            //foreach (string n in pt[])

            //{

            //    n = "indexer concept";

            //}

        }

    }

}