/*readonly
The readonly keyword is different from the const keyword. A const field can only be 
initialized at the declaration of the field. A readonly field can be initialized either at the
 declaration or in a constructor.
*/
using System;
public class ReadOnlyTest 
{
   class MyClass 
   {
      public int x;
      public readonly int y = 25; // Initialize a readonly field
      public readonly int z;

      public MyClass() 
      {
         z = 24;   // Initialize a readonly instance field
      }

      public MyClass(int p1, int p2, int p3) 
      {
         x = p1; 
         y = p2; 
         z = p3;
      }
   }
   public static void Main() 
   {
      MyClass p1= new MyClass(11, 21, 32);   // OK
      Console.WriteLine("p1: x={0}, y={1}, z={2}" , p1.x, p1.y, p1.z);   
      MyClass p2 = new MyClass();
      p2.x = 55;   // OK
      Console.WriteLine("p2: x={0}, y={1}, z={2}" , p2.x, p2.y, p2.z);
   }
}