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Object???Oriented Programming with Swift 2

You're reading from  Object???Oriented Programming with Swift 2

Product type Book
Published in Jan 2016
Publisher
ISBN-13 9781785885693
Pages 332 pages
Edition 1st Edition
Languages
Author (1):
Gaston C. Hillar Gaston C. Hillar
Profile icon Gaston C. Hillar

Table of Contents (16) Chapters

Object–Oriented Programming with Swift 2
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
1. Objects from the Real World to Playground 2. Structures, Classes, and Instances 3. Encapsulation of Data with Properties 4. Inheritance, Abstraction, and Specialization 5. Contract Programming with Protocols 6. Maximization of Code Reuse with Generic Code 7. Object-Oriented Programming and Functional Programming 8. Extending and Building Object-Oriented Code Exercise Answers Index

Understanding automatic reference counting


Automatic reference counting is very easy to understand. Imagine that we have to distribute the items that we store in a box. After we distribute all the items, we must throw the box in a recycle bin. We cannot throw the box to the recycle bin when we still have one or more items in it. Seriously, we don't want to lose the items we have to distribute because they are very expensive.

The problem has a very easy solution; we just need to count the number of items that remain in the box. When the number of items in the box reaches zero, we can get rid of the box.

Tip

One or more variables can hold a reference to a single instance of a class. Thus, it is necessary to count the number of references to an instance before Swift can get rid of an instance. When the number of references to a specific instance reaches zero, Swift can automatically and safely remove the instance from memory because nobody needs this specific instance anymore.

For example, you...

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