Apple has said that Swift developers should prefer value types over reference types, and it seems that they have also taken that philosophy to heart. If we look at the Swift standard library (http://swiftdoc.org), we will see that the majority of types are implemented using structures. The reason Apple is able to implement the majority of Swift's standard library with structures is that, in Swift, structures have many of the same functionalities as classes. There are, however, some fundamental differences between classes and structures, and we will be looking at these differences later in this chapter.
In Swift, a structure is a construct that allows us to encapsulate the properties, methods, and initializers of an instance into a single type. They can also include other items, such as subscripts. However, we are going to focus on the basic items that make up a structure. This description may sound a lot like how we described classes in the last section. This is because classes...