Improving existing code—refactoring—is one of the most common tasks you’ll face as a programmer.   Five Lines of Code  teaches you clear and actionable refactoring rules that you can apply without relying on intuitive judgements such as “code smells.” It’s written for working developers, guiding you step by step through applying refactoring patterns to the codebase of a 2D puzzle game. Following the author’s expert perspective—that refactoring and code smells can be learned by following a concrete set of principles—you’ll learn when to refactor your code, what patterns to apply to what problem, and the code characteristics that indicate it’s time for a rework. Thanks to this hands-on guide, you’ll find yourself programming faster while still delivering high-quality code that your teammates will love to work with. about the technologyRefactoring is a fact of life. All code is imperfect, and refactoring is a systematic process you can use to improve the quality of your codebase. Whatever your architecture, choice of OO language, or skill as a programmer, the continuous design improvements of refactoring make your code simpler, more readable, and less prone to bugs. You’ll be amazed at the productivity boost of adding refactoring to your code hygiene routine—it’s quicker to hammer out bad code and then improve it than spending hours writing good code in the first place! about the book Five Lines of Code  teaches working developers the shortcuts to quality code. You’ll follow author Christian Clausen’s unique approach to teaching refactoring that’s focused on concrete rules, and getting any method down to five lines or less to implement! There’s no jargon or tricky automated-testing skills required, just easy guidelines and patterns illustrated by detailed code samples. Chapter by chapter you’ll put techniques into action by refactoring a complete 2D puzzle game. Before you know it, you’ll be making serious and tangible improvements to your codebase. what's inside The symptoms of bad code The extracting method, introducing strategy pattern, and many other refactoring patterns Modifying code safely, even when you don’t understand it Writing stable code that enables change-by-addition Proper compiler practices Writing code that needs no comments Real-world practices for great refactoring about the readerFor developers who know an object-oriented programming language. about the author Christian Clausen  works as a Technical Agile Coach teaching teams how to properly refactor their code. Previously he worked as a software engineer on the Coccinelle semantic patching project, an automated refactoring tool. He has an MSc in computer science, and five years’ experience teaching software quality at a university level.