Difference between readonly and const keyword in C#

readonly keyword

readonly keyword is used to define a variable which can be assigned once after declaration either during declaration or in constructor. const keyword is used to define a constant to be used in the program. Following is the valid usage of a readonly and const keywords in C#.

Example

 Live Demo

using System.IO;
using System;

public class Program {
   public const int VALUE = 10;
   public readonly int value1;

   Program(int value){
      value1 = value;
   }
   public static void Main() {
      Console.WriteLine(VALUE);
      Program p1 = new Program(11);
      Console.WriteLine(p1.value1);
   }
}

Output

10
11

Following are some of the important differences between readonly and const keywords.