Book Image

Mastering Swift 2

By : Jon Hoffman
Book Image

Mastering Swift 2

By: Jon Hoffman

Overview of this book

<p><span id="description" class="sugar_field">At their Worldwide Developer’s conference (WWDC) in 2015, Apple announced Swift 2, a major update to the innovative programming language they first unveiled to the world the year before. Swift 2 features exciting enhancements to the original iteration of Swift, acting, as Apple put it themselves as “a successor to the C and Objective-C languages.” – This book demonstrates how to get the most from these new features, and gives you the skills and knowledge you need to develop dynamic iOS and OS X applications.<br /> </span></p> <p><span id="description" class="sugar_field">Learn how to harness the newest features of Swift 2 todevelop advanced applications on a wide range of platforms with this cutting-edge development guide. Exploring and demonstrating how to tackle advanced topics such as Objective-C interoperability, ARC, closures, and concurrency, you’ll develop your Swift expertise and become even more fluent in this vital and innovative language. With examples that demonstrate how to put the concepts into practice, and design patterns and best practices, you’ll be writing better iOS and OSX applications in with a new level of sophistication and control.</span></p>
Table of Contents (24 chapters)
Mastering Swift 2
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Free Chapter
1
Taking the First Steps with Swift
2
Learning about Variables, Constants, Strings, and Operators
Index

Calculated subscripts


While the preceding example is very similar to using the stored properties in a class or structure, we can also use subscripts in a similar manner to the computed properties. Let's see how to do this:

struct MathTable {
    var num: Int
   
    subscript(index: Int) -> Int {
        return num * index
    }
}

In the preceding example, we used an array as the backend storage mechanism for the subscript. In this example, we use the value of the subscript to calculate the return value. We will use this subscript as follows:

var table = MathTable(num: 5)
print(table[4])

This example will display the calculated value of 5 (the number defined in the initialization) times 4 (the subscript value), which is equal to 20.