Advantages to Using Private Static Methods

Question

When creating a class that has internal private methods, usually to reduce code duplication, that don\'t require the use of any instance fields, are there performance or mem

Answer 1

When I'm writing a class, most methods fall into two categories:

• Methods that use/change the current instance's state.
• Helper methods that don't use/change the current object's state, but help me compute values I need elsewhere.

Static methods are useful, because just by looking at its signature, you know that the calling it doesn't use or modify the current instance's state.

Take this example:

public class Library
{
    private static Book findBook(List books, string title)
    {
        // code goes here
    }
}

If an instance of library's state ever gets screwed up, and I'm trying to figure out why, I can rule out findBook as the culprit, just from its signature.

I try to communicate as much as I can with a method or function's signature, and this is an excellent way to do that.