Book Image

PHP 7 Programming Cookbook

By : Doug Bierer
Book Image

PHP 7 Programming Cookbook

By: Doug Bierer

Overview of this book

PHP 7 comes with a myriad of new features and great tools to optimize your code and make your code perform faster than in previous versions. Most importantly, it allows you to maintain high traffic on your websites with low-cost hardware and servers through a multithreading web server. This book demonstrates intermediate to advanced PHP techniques with a focus on PHP 7. Each recipe is designed to solve practical, real-world problems faced by PHP developers like yourself every day. We also cover new ways of writing PHP code made possible only in version 7. In addition, we discuss backward-compatibility breaks and give you plenty of guidance on when and where PHP 5 code needs to be changed to produce the correct results when running under PHP 7. This book also incorporates the latest PHP 7.x features. By the end of the book, you will be equipped with the tools and skills required to deliver efficient applications for your websites and enterprises.
Table of Contents (22 chapters)
PHP 7 Programming Cookbook
Credits
Foreword
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Building a bubble sort


The classic bubble sort is an exercise often assigned to university students. Nonetheless, it's important to master this algorithm as there are many occasions where built-in PHP sorting functions do not apply. An example would be sorting a multi-dimensional array where the sort key is not the first column.

The way the bubble sort works is to recursively iterate through the list and swap the current value with the next value. If you want items to be in ascending order, the swap occurs if the next item is less than the current item. For descending order, the swap occurs if the reverse is true. The sort is concluded when no more swaps occur.

In the following diagram, after the first pass, Grape and Banana are swapped, as are Orange and Cherry. After the 2nd pass, Grape and Cherry are swapped. No more swaps occur on the last pass, and the bubble sort ends:

How to do it...

  1. We do not want to actually move the values around in the array; that would be horribly expensive in terms...