Program for Reverse String without in-build function in C# asp.net

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace reversestring

{

    class Program

    {

        static void Main(string[] args)

        {

            string Str, Revstr = "";

            int Length;

            Console.Write("Enter A String : ");

            Str = Console.ReadLine();

            Length = Str.Length - 1;

           

            while (Length >= 0)

            {

                Revstr = Revstr + Str[Length];

                Length--;

            }

            Console.WriteLine("Reverse  String  Is  {0}", Revstr);

            Console.ReadLine();

        }

    }

}