C# 7 and .NET: Designing Modern Cross-platform Applications

Making a field constant

If the value of a field will never ever change, you can use the const keyword and assign the value at compile time.

Inside the Person class, add the following code:

// constants 
public const string Species = "Homo Sapien"; 

Inside the Main method, change the code to look like this. Note that, to read a constant field, you must write the name of the class, not the name of an instance of the class:

WriteLine($"{p1.Name} is a {Person.Species}"); 

Run the application and view the additional output:

Bob Smith is a Homo Sapien

Examples of the const fields in Microsoft types include System.Int32.MaxValue and System.Math.PI because neither value will ever change, as you can see in the following screenshot:

Good Practice