Chapter 14. Use Class Instance Variables

In the last chapter we saw how you can add methods to your classes, methods that concern themselves with the issues that affect a class as a whole. But wherever you have code, you’re going to want to have data, which raises the question of where to store your class-level data. In this chapter we will look at the two alternatives that Ruby gives us for storing class-level data, the class variable, and the class instance variable.

We are going to start by looking at class variables, those Ruby things that start with @@ and seem to be the easy answer to storing your class-related information. Sadly, we will discover that class variables behave in some unfortunate ways, making them less of a solution and ...

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