Demonstrate a virtual method

   

/*
C#: The Complete Reference 
by Herbert Schildt 

Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/


// Demonstrate a virtual method. 
 
using System; 
 
class Base { 
  // Create virtual method in the base class.  
  public virtual void who() { 
    Console.WriteLine("who() in Base"); 
  } 
} 
 
class Derived1 : Base { 
  // Override who() in a derived class. 
  public override void who() { 
    Console.WriteLine("who() in Derived1"); 
  } 
} 
 
class Derived2 : Base { 
  // Override who() again in another derived class. 
  public override void who() { 
    Console.WriteLine("who() in Derived2"); 
  } 
} 
 
public class OverrideDemo { 
  public static void Main() { 
    Base baseOb = new Base(); 
    Derived1 dOb1 = new Derived1(); 
    Derived2 dOb2 = new Derived2(); 
 
    Base baseRef; // a base-class reference 
 
    baseRef = baseOb;  
    baseRef.who(); 
 
    baseRef = dOb1;  
    baseRef.who(); 
 
    baseRef = dOb2;  
    baseRef.who(); 
  } 
}