Book Image

Mastering Swift 5.3 - Sixth Edition

By : Jon Hoffman
Book Image

Mastering Swift 5.3 - Sixth Edition

By: Jon Hoffman

Overview of this book

Over the years, Mastering Swift has proven itself among developers as a popular choice for an in-depth and practical guide to the Swift programming language. This sixth edition comes with the latest features, an overall revision to align with Swift 5.3, and two new chapters on building swift from source and advanced operators. From the basics of the language to popular features such as concurrency, generics, and memory management, this in-depth guide will help you develop your expertise and mastery of the language. As you progress, you will gain practical insights into some of the most sophisticated elements in Swift development, including protocol extensions, error handling, and closures. The book will also show you how to use and apply them in your own projects. In later chapters, you will understand how to use the power of protocol-oriented programming to write flexible and easier-to-manage code in Swift. Finally, you will learn how to add the copy-on-write feature to your custom value types, along with understanding how to avoid memory management issues caused by strong reference cycles. By the end of this Swift book, you will have mastered the Swift 5.3 language and developed the skills you need to effectively use its features to build robust applications.
Table of Contents (23 chapters)
21
Other Books You May Enjoy
22
Index

Constants and variables

Constants and variables associate an identifier (such as myName or currentTemperature) with a value of a particular type (such as the String or Integer type), where the identifier can be used to retrieve the value. The difference between a constant and a variable is that a variable can be updated or changed, while a constant cannot be changed once a value is assigned to it.

Constants are good for defining values that you know will never change, like the temperature that water freezes at or the speed of light. Constants are also good for defining a value that we use many times throughout our application, such as a standard font size or the maximum number of characters in a buffer. There will be numerous examples of constants throughout this book, and it is recommended that we use constants rather than variables whenever possible.

Variables tend to be more common in software development than constants. This is mainly because developers tend to prefer...