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 multi-parameter function

We are not limited to just one parameter with our functions; we can also define multiple parameters. To create a multi-parameter function, we list the parameters in the parentheses and separate the parameter definitions with commas. Let's look at how to define multiple parameters in a function:

func sayHello(name: String, greeting: String) {  
  print("\(greeting) \(name)") 
} 

In the preceding example, the function accepts two arguments: name and greeting. We then print a greeting to the console using both parameters.

Calling a multi-parameter function is a little different from calling a single-parameter function. When calling a multi-parameter function, we separate the parameters with commas. We also need to include the parameter name for all the parameters. The following example shows how to call a multi-parameter function:

sayHello...