All sample code in this book was written in Swift 4.2 with Xcode 10.0 on a Mac running macOS Mojave. To follow along with all the examples in this book you must have at least Xcode 10.0 installed on your machine. It is recommended that you also have at least macOS Mojave installed on your Mac because not all code samples are compatible with older versions of macOS.

This book assumes that you are somewhat familiar with Swift and iOS development. If you have no experience with Swift at all, it is recommended that you skim through Apple's Swift manual and go over the basics of iOS development. You don't have to be an expert on iOS development yet, but a solid foundation won't hurt you since the pacing of the book is aimed at somewhat experienced developers.

You can download the example code files for this book from your account at www.packt.com. If you purchased this book elsewhere, you can visit www.packt.com/support and register to have the files emailed directly to you.

You can download the code files by following these steps:

1. Log in or register at www.packt.com.
2. Select the SUPPORT tab.
3. Click on Code Downloads & Errata.
4. Enter the name of the book in the Search box and follow the onscreen instructions.

Once the file is downloaded, please make sure that you unzip or extract the folder using the latest version of:

• WinRAR/7-Zip for Windows
• Zipeg/iZip/UnRarX for Mac
• 7-Zip/PeaZip for Linux

The code bundle for the book is also hosted on GitHub at https://github.com/PacktPublishing/Mastering-iOS-12-Programming-Third-Edition. In case there's an update to the code, it will be updated on the existing GitHub repository.

We also have other code bundles from our rich catalog of books and videos available at https://github.com/PacktPublishing/. Check them out!

We also provide a PDF file that has color images of the screenshots/diagrams used in this book. You can download it here: https://www.packtpub.com/sites/default/files/downloads/9781789133202_ColorImages.pdf.

There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "Mount the downloaded WebStorm-10*.dmg disk image file as another disk in your system."

A block of code is set as follows:

func doSomething(completionHandler: (Int) -> Void) {
  // perform some actions
  var result = theResultOfSomeAction
  completionHandler(result)
}

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "Select System info from the Administration panel."