C#.NET Readonly

A readonly field can be initialized either at the declaration or in a constructor.

Example Program for C#.NET read only

Program

using System;

namespace ReadOnly

{

    class Program

    {

        static void Main(string[] args)

        {

            Maths m = new Maths();

            Console.ReadKey();

        }

    }

    class Maths

    {

        const int a = 10;

        readonly int b = 20;

        public Maths()

        {

            b = 25; //Assigning value to ready only variable in constructor

            // a = 20; //Value cannot be assigned to Const variable

            Console.WriteLine(b);

        }

    }

}

Output
25