Summary
In this chapter, you learned how to write protocols and how to make classes, structures, and enumerations conform to them. You also learned how to extend the capabilities of a class by using an extension. Finally, you learned how to handle errors using the do-catch block.
It may seem rather abstract and hard to understand now, but as you will see in Part 3 of this book, you will use protocols to implement common functionalities in different parts of your program instead of writing the same program over and over. You will see how useful extensions are in organizing your code, which makes it easy to maintain. Last but not least, you'll see how good error handling makes it easy to pinpoint the mistakes you made while coding your app.
In the next chapter, you will start writing your first iOS application by creating the screens for it using storyboards, which allow you to rapidly prototype an application without having to type a lot of code.