OOPS Example

Try this example which illustrates inheritance, polymorphism and encapsulation. What did you have in mind for the fourth?

using System;




class Parent // encapsulation - encapsulates data and method into a class
{
  private string name; // data hiding - hides state from outside code
 
  public string Name  // property exposes state to outside code
  {
    get { return name; }
    set { name = value; }
  }


  public Parent(string name)
  {
     this.name = name;
  }


  public Parent(){}


  public void MyMethod()
  {
     Console.WriteLine("Hello from Parent.MyMethod");
  }


  public virtual void MyVirtMethod() 
  {
     Console.WriteLine("Hello from Parent.MyVirtMethod");
  }


}




class Derived : Parent // inheritance - inherits from Derived
{


  public override void MyVirtMethod() 
  {
     Console.WriteLine("Hello from Derived.MyVirtMethod");
  }


}


class Test
{
  static void Main()
  {
      Derived d = new Derived();
      d.MyMethod(); // inheritance - MyMethod inherited from Parent
      Parent p = d;
      p.MyVirtMethod(); // polymorphism - Derived.MyVirtMethod called because p refers to a Derived object 
      p = new Parent("Fred");
      Console.WriteLine(p.Name);      
      Console.ReadKey();
  }
}