Book Image

Mastering Swift 4 - Fourth Edition

By : Jon Hoffman
Book Image

Mastering Swift 4 - Fourth Edition

By: Jon Hoffman

Overview of this book

<p>Swift is the definitive language for Apple development today. It's a vital part of any iOS and macOS developer's skillset, helping them to build the most impressive and popular apps on the App Store - the sort of apps that are essential to iPhone and iPad users every day. With version 4.0, the Swift team has added new features to improve the development experience, making it easier to get the results you want and customers expect.</p> <p>Inside, you'll find the key features of Swift 4.0 and quickly learn how to use the newest updates to your development advantage. From Objective-C interoperability and ARC to closures and concurrency, this advanced Swift guide will develop your expertise and help you become fluent in this vital programming language.</p> <p>We'll give you an in-depth knowledge of some of the most sophisticated elements of Swift development, including protocol extensions, error-handling, design patterns, and concurrency. We'll guide you on how to use and apply them in your own projects. You'll see how to leverage the power of protocol-oriented programming to write flexible and easier-to-manage code.</p>
Table of Contents (24 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
Free Chapter
1
Taking the First Steps with Swift
2
Learning about Variables, Constants, Strings, and Operators

Memory management


As I mentioned at the start of this chapter, structures are value types and classes are reference types. What this means is that when we pass an instance of a structure within our application, such as a parameter of a method, we create a new instance of the structure in the memory. This new instance of the structure is only valid while the application is in the scope where the structure was created. Once the structure goes out of scope, the new instance of the structure is destroyed and the memory is released. This makes memory management of structures pretty easy and somewhat painless.

Classes, on the other hand, are reference types. This means that we allocate memory for the instance of the class only once, when it is initially created. When we pass an instance of the class within our application, either as a function argument or by assigning it to a variable, we really pass a reference to where the instance is stored in memory. Since the instance of a class may be referenced...