Book Image

Learning Swift Second Edition - Second Edition

By : Andrew J Wagner
Book Image

Learning Swift Second Edition - Second Edition

By: Andrew J Wagner

Overview of this book

Swift is Apple’s new programming language and the future of iOS and OS X app development. It is a high-performance language that feels like a modern scripting language. On the surface, Swift is easy to jump into, but it has complex underpinnings that are critical to becoming proficient at turning an idea into reality. This book is an approachable, step-by-step introduction into programming with Swift for everyone. It begins by giving you an overview of the key features through practical examples and progresses to more advanced topics that help differentiate the proficient developers from the mediocre ones. It covers important concepts such as Variables, Optionals, Closures, Generics, and Memory Management. Mixed in with those concepts, it also helps you learn the art of programming such as maintainability, useful design patterns, and resources to further your knowledge. This all culminates in writing a basic iOS app that will get you well on your way to turning your own app ideas into reality.
Table of Contents (19 chapters)
Learning Swift Second Edition
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Control flow


Objective-C has many of the same control flow paradigms as Swift. We will go through each of them quickly, but before we do, let's take a look at the Objective-C equivalent of print:

var name = "Sarah"
println("Hello \(name)")
NSString *name = @"Sarah";
NSLog(@"Hello %@", name);

Instead of print, we are using a function called NSLog. Objective-C does not have string interpolation, so NSLog is a somewhat more complex solution than print. The first argument to NSLog is a string that describes the format to be printed out. This includes a placeholder for each piece of information we want to log that indicates the type it should expect. Every placeholder starts with a percent symbol. In this case, we are using an at-symbol to indicate what we are going to be substituting in a string. Every argument after the initial format will be substituted for the placeholders in the same order they are passed in. Here, this means that it will end up logging Hello Sarah just like the Swift code...