Seal a member

class Shape{//from  j  a  v a 2s .  co m
  public virtual int Area{
     get{
        return 0;
     }
  }
}

class Rectangle:Shape{
   public int width;
   public int height;
   
   public sealed override int Area{
      get{
         return width * height;
      }
   }
}

using System;//  j  av a 2 s  . co  m

public class BaseClass
{
  public string lastName;
  public string firstName;

  public BaseClass(string lastName, string firstName)
  {
    this.lastName = lastName;
    this.firstName = firstName;
  }

  public virtual void Accelerate()
  {
    Console.WriteLine("In BaseClass Accelerate() method");
    Console.WriteLine(firstName + " accelerating");
  }

}

public class DerivedClass : BaseClass
{
  public DerivedClass(string lastName, string firstName) : base(lastName, firstName)
  {
  }

  sealed public override void Accelerate()
  {
    Console.WriteLine("In DerivedClass Accelerate() method");
    Console.WriteLine(firstName + " accelerating");
  }

}

class MainClass
{

  public static void Main()
  {
    DerivedClass myDerivedClass = new DerivedClass("A", "M");

    Console.WriteLine("Calling myDerivedClass.Accelerate()");
    myDerivedClass.Accelerate();
  }
}