Book Image

Swift 3 Object-Oriented Programming - Second Edition

By : Gaston C. Hillar
Book Image

Swift 3 Object-Oriented Programming - Second Edition

By: Gaston C. Hillar

Overview of this book

Swift has quickly become one of the most-liked languages and developers’ de-facto choice when building applications that target iOS and macOS. In the new version, the Swift team wants to take its adoption to the next level by making it available for new platforms and audiences. This book introduces the object-oriented paradigm and its implementation in the Swift 3 programming language to help you understand how real-world objects can become part of fundamental reusable elements in the code. This book is developed with XCode 8.x and covers all the enhancements included in Swift 3.0. In addition, we teach you to run most of the examples with the Swift REPL available on macOS and Linux, and with a Web-based Swift sandbox developed by IBM capable of running on any web browser, including Windows and mobile devices. You will organize data in blueprints that generate instances. You’ll work with examples so you understand how to encapsulate and hide data by working with properties and access control. Then, you’ll get to grips with complex scenarios where you use instances that belong to more than one blueprint. You’ll discover the power of contract programming and parametric polymorphism. You’ll combine generic code with inheritance and multiple inheritance. Later, you’ll see how to combine functional programming with object-oriented programming and find out how to refactor your existing code for easy maintenance.
Table of Contents (17 chapters)
Swift 3 ObjectOriented Programming - Second Edition
Credits
About the Author
Acknowledgement
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Understanding initialization and its customization


When you ask Swift to create an instance of a specific class, something happens under the hood. Swift creates a new instance of the specified type, allocates the necessary memory, and then executes the code specified in the initializer.

Note

You can think of initializers as equivalents of constructors in other programming languages such as C# and Java.

When Swift executes the code within an initializer, there is already a live instance of the class. Thus, we have access to the properties and methods defined in the class. However, we must be careful in the code we put in the initializer because we might end up generating huge delays when we create instances of the class.

Note

Initializers are extremely useful to execute setup code and properly initialize a new instance.

So, for example, before you can call either the calculatedArea or calculatedPerimeter method, you want both the semiMajorAxis and semiMinorAxis fields for each new Ellipse instance...