Before you can improve your project structure with value types and protocols, it's a good idea to improve upon your structure in general. We haven't really thought about the reuse possibilities of certain aspects of the Hello-Contacts app, which results in code that's harder to maintain in the long run. This is especially true for larger projects that are built over an extended period of time.
If you take a look at the source code for this project in the book's code bundle, you'll find that the project was slightly modified. First, all the project files were put together in sensible groups. Doing so makes it easier for you to navigate your project's files, and it creates a natural place for certain files, as shown in the following screenshot:
The structure applied in this project is merely a suggestion; if you feel that...
