Book Image

Learn iOS 11 Programming with Swift 4 - Second Edition

By : Craig Clayton
Book Image

Learn iOS 11 Programming with Swift 4 - Second Edition

By: Craig Clayton

Overview of this book

<p>You want to build iOS applications but where do you start? Forget sifting through tutorials and blog posts, this book is a direct route into iOS development, taking you through the basics and showing you how to put the principles into practice. So take advantage of this developer-friendly guide and start building applications that may just take the App Store by storm!</p> <p>Whether you're an experienced programmer or a complete novice, this book guides you through every facet of iOS development. From Xcode and Swift, the building blocks of modern iOS development, you'll quickly gain a solid foundation to begin venturing deeper into your development journey. Experienced programmers can jump right in and learn the latest iOS 11 features.</p> <p>You'll also learn advanced topics of iOS design, such as gestures and animations, to give your app the edge. Explore the latest developments in Swift 4 and iOS 11 by incorporating new features, custom-rich notifications, drag and drop features, and the latest developments in SiriKit. With further guidance on beta testing with TestFlight, you'll quickly learn everything you need to get your project on the App Store!</p>
Table of Contents (36 chapters)
Title Page
Copyright and Credits
Packt Upsell
Contributors
Preface
Free Chapter
1
Getting Familiar with Xcode
Index

Control flow


In programming, control flow is the order in which your code is executed. When working with Swift, we can use a variety of control statements. Loops, in particular, are useful for when you want to repeat a task multiple times. Let's take a look at a few different types of loop.

The for...in loop

One of the most common control statements is a for...in loop. It allows you to iterate over each element in a sequence. Let's see what a for...in loop looks like:

for <value> in <sequence> { 
 // Code here 
} 

We start the for...in loop with for, which is proceeded by <value>. This is actually a local constant (only the for...in loop can access it) and can be any name you like. Typically, you will want to give this value an expressive name. Next, we have in, which is followed by <sequence>. This is where we want to give it our sequence of numbers. Let's write the following into Playgrounds:

Notice that, in our Debug panel, we see all of the numbers we wanted in our...