A base class reference can refer to a derived class object : Class Inheritance « Class Interface « C# / C Sharp

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A base class reference can refer to a derived class object
A base class reference can refer to a derived class object

/*
C#: The Complete Reference 
by Herbert Schildt 

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


// A base class reference can refer to a derived class object. 
 
using System; 
 
class 
  public int a; 
 
  public X(int i) { 
    a = i; 
  

 
class Y : X 
  public int b; 
 
  public Y(int i, int j: base(j) { 
    b = i; 
  

 
public class BaseRef 
  public static void Main() { 
    X x = new X(10)
    X x2;  
    Y y = new Y(56)
 
    x2 = x; // OK, both of same type 
    Console.WriteLine("x2.a: " + x2.a)
 
    x2 = y; // still Ok because Y is derived from X 
    Console.WriteLine("x2.a: " + x2.a)
 
    // X references know only about X members 
    x2.a = 19// OK 
//    x2.b = 27; // Error, X doesn't have a b member 
  
}


           
       
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