Book Image

Mastering Swift 5 - Fifth Edition

By : Jon Hoffman
Book Image

Mastering Swift 5 - Fifth Edition

By: Jon Hoffman

Overview of this book

Over the years, the Mastering Swift book has established itself amongst developers as a popular choice as an in-depth and practical guide to the Swift programming language. The latest edition is fully updated and revised to cover the new version: Swift 5. Inside this book, you'll find the key features of Swift 5 easily explained with complete sets of examples. From the basics of the language to popular features such as concurrency, generics, and memory management, this definitive guide will help you develop your expertise and mastery of the Swift language. Mastering Swift 5, Fifth Edition will give you an in-depth knowledge of some of the most sophisticated elements in Swift development, including protocol extensions, error handling, and closures. It will guide you on how to use and apply them in your own projects. Later, you'll see how to leverage the power of protocol-oriented programming to write flexible and easier-to-manage code. You will also see how to add the copy-on-write feature to your custom value types and how to avoid memory management issues caused by strong reference cycles.
Table of Contents (20 chapters)

Using a single parameter function

The syntax that's used to define a function in Swift is very flexible. This flexibility makes it easy for us to define simple C-style functions, or more complex functions, with local and external parameter names, which we will see later in this chapter. Let's look at some examples of how to define functions. The following example accepts one parameter and does not return any value back to the code that called it:

func sayHello(name: String) -> Void {  
  let retString = "Hello " + name  
  print(retString) 
} 

In the preceding example, we defined a function named sayHello() that accepted one parameter, named name. Inside the function, we printed out a greeting to the name of the person. Once the code within the function is executed, the function exits, and control is returned back to the code that called it. Rather than...