Sealed Class

Sealed class is used to define the inheritance level of a class.

The sealed modifier is used to prevent derivation from a class. An error occurs if a sealed class is specified as the base class of another class.

Some points to remember:   

1.  A class, which restricts inheritance for security reason is declared, sealed class.
2.  Sealed class is the last class in the hierarchy.
3.  Sealed class can be a derived class but can't be a base class.
4.  A sealed class cannot also be an abstract class. Because abstract class has to provide functionality and here we are 
     restricting it to inherit.

Practical demonstration of sealed class

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace sealed_class

{

    class Program

    {

        public sealed class BaseClass

        {

            public void Display()

        {

Console.WriteLine("This is a sealed class which can;t be further inherited");

        }

    }

        public class Derived : BaseClass

        {

          // this Derived class can;t inherit BaseClass because it is sealed

        }

   

        static void Main(string[] args)

        {

            BaseClass obj = new BaseClass();

            obj.Display();

            Console.ReadLine();

        }

    }

}