Chris Minnick - Writing Computer Code

WRITING COMPUTER CODE

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John Wiley & Sons, Inc.
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Hoboken, NJ 07030-5774

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Copyright 2016 by John Wiley & Sons, Inc., Hoboken, New Jersey

Published simultaneously in Canada

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Library of Congress Control Number: 2016941390
ISBN 978-1-119-17730-2 (pbk); ISBN 978-1-119-17732-6 (ebk); ISBN 978-1-119-17733-3 (ebk)

1. Table of Contents

SO, YOU WANT TO GET STARTED WRITING REAL COMPUTER CODE! Maybe youve played with drag-and-drop programming languages or youve done modding in Minecraft, and youre ready for the next level. Great! There are currently more than 500 different languages for coding on computers (which isnt very many, when you consider that there are about 6,500 human languages!). Youre about to learn the most popular languages that are used by millions of coders all over the world.

In this book, youll learn to use HTML5, CSS3, and JavaScript to create programs for computers. More people have used these three computer-coding languages than any other coding language thats ever been invented. In fact, every single website that you visit makes use of these three languages. Thats why we think youve made a great decision by beginning your journey into the world of coding by picking up Writing Computer Code.

Computer code is fun and easy to learn. With some determination and a lot of imagination, youll be creating your very own computer programs in no time!

Just as the only way to become a great athlete or musician is to practice, practice, practice, the only way to become a computer programmer is to write code, write code, write code!

This book is put together as a series of projects with steps for constructing each project from start to finish. The projects also build upon one another, so that by the end of the book youll have an animated robot that you can control with your mouse and continue to modify and improve long after you finish all the projects.

Heres what you need to do the projects in this book:

• A computer running the Windows, Mac OS X, or Linux operating system
• A web browser, like Chrome, Firefox, or Safari
• An Internet connection

As you work through each project, keep in mind the following:

• Code and web addresses are in monofont. If youre reading this as an ebook, you can click web addresses, like www.dummies.com , to visit that website.
• When youre getting started, the best way to learn is to see how other people do it. For this reason, weve included pictures for every important step in the book, and all our examples are online at http://jsfiddle.net/user/watzthis/fiddles . If you want to check your work, or just copy ours, be sure to look at both of these.
• Every project wraps up with a last look at the projects big ideas in coding. The big ideas consist of codes and concepts youll find useful for future projects.
• Coding isnt that hard, but it does come with a lot of technical details. If you dont feel like reading all the explanations, just skip ahead to the next code example and try it out.

We already know that youre ready and willing to code. Because youre reading this, we know youre fully qualified and able to get started right away. We dont make many assumptions, but here are the things we wanted to mention upfront:

• You should be comfortable with using a web browser to visit websites, and with typing on a keyboard. The projects in this book wont likely work on a phone or tablet without a keyboard.
• Youre comfortable with very basic math. Were talking about addition, subtraction, multiplication, and division. We dont require anything very advanced at all, but basic math is an important part of programming.
• You have the patience and dedication to stick with it and troubleshoot bugs. We guarantee that programming can be a lot of fun, but we also guarantee that it can be frustrating when you have to track down the one typo or missed command that is making your whole program not work. Stick with it!

Thats really all there is to it. If you get stuck, keep in mind that many problems in writing computer code happen simply because of spelling errors or words that you type that a computer cant understand. Proceed slowly and carefully, and youll do great!

As you read through the projects in this book, youll see a few icons. The icons point out different things:

Watch out! The Warning icon marks important information that you can use to avoid common pitfalls when coding.