Head First PHP & MySQL

Chapter 8. Eliminate Duplicate Code: Sharing is caring

Umbrellas aren’t the only thing that can be shared. In any web application you’re bound to run into situations where the same code is duplicated in more than one place. Not only is this wasteful, but it leads to maintenance headaches since you will inevitably have to make changes, and these changes will have to be carried out in multiple places. The solution is to eliminate duplicate code by sharing it. In other words, you stick the duplicate code in one place, and then just reference that single copy wherever you need it. Eliminating duplicate code results in applications that are more efficient, easier to maintain, and ultimately more robust.

Exercise

The Mismatch application has evolved since you last saw it, with improved navigation and a more consistent look and feel. But these improvements have come at a cost... duplicate code. Just by looking at the pages themselves, see if you can figure out what parts of Mismatch might represent a duplicate code problem. Circle and annotate these application parts, and also write down anything not visible that you think might also have code duplication issues.

Exercise Solution

The Mismatch application ...