Tip

Constant and read-only members

Let other users know how useful this tip is by rating it below. Got a tip or code of your own you'd like to share? Submit it here!

What are constant and read-only members? Constant and read-only members specify that the value of the field or the local variable cannot be modified. A constant member can be declared using the keyword const, whereas a read-only member would be declared using the readonly modifier.The value of a const member is calculated at compile time. Therefore you cannot set a dynamic value to a const member. A read-only modifier specifies that the member can have its value set once only, and afterwards it becomes read- only. Therefore read-only can be used to set dynamic value.

Save the code below as ConstReadonly.cs, Compile C:>csc ConstReadonly.cs and run C:>ConstReadonly.


ConstReadonly.cs

using System;
class Circle
{
         private const double pi=3.14; //declare a Constant
Member 
         public readonly int radius; //declare a Readonly
Member

         public Circle(int r)
         {  
                   radius = r; //readonly member can be set
only once and afterward becomes readonly 
         }
         public double Area()
         {
                  return pi * radius * radius; 
         } 
} 

class Test 
{
                public static void Main(String [] args) 
               { 
                        Circle c = new Circle(10);
                        Console.WriteLine(c.Area());
                }
}


This was first published in January 2003

There are Comments. Add yours.

 
TIP: Want to include a code block in your comment? Use <pre> or <code> tags around the desired text. Ex: <code>insert code</code>

REGISTER or login:

Forgot Password?
By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy
Sort by: OldestNewest

Forgot Password?

No problem! Submit your e-mail address below. We'll send you an email containing your password.

Your password has been sent to:

Disclaimer: Our Tips Exchange is a forum for you to share technical advice and expertise with your peers and to learn from other enterprise IT professionals. TechTarget provides the infrastructure to facilitate this sharing of information. However, we cannot guarantee the accuracy or validity of the material submitted. You agree that your use of the Ask The Expert services and your reliance on any questions, answers, information or other materials received through this Web site is at your own risk.