Appendix: An Introduction to Swift
While there are numerous programming languages and tools you can use to create iOS apps, the most popular tool is Xcode, which allows you to write iOS apps using two languages: Objective-C or Swift. Originally, Objective-C was the only language that Xcode supported, but in 2014, Apple introduced Swift. Two crucial advantages of Swift over Objective-C are that Swift is easier to read and write, and Swift is faster than Objective-C. While many older iOS apps are written in Objective-C, Swift is the programming language of the future for not only iOS but also for macOS, tvOS, watchOS, and any future operating systems Apple may develop in the future.
The best way to learn Swift is to use a special feature of Xcode ...