Many programming books for beginners fall into two categories The first category includes books that don’t teach programming so much as game creation software or languages that simplify so much that what is taught is no longer programming The other category consists of books that teach programming like a mathematics textbook all principles and concepts with few real-life applications for the reader This book takes a different approach and teaches you how to program by making video games I show the source code for the games right up front and explain programming principles from the examples This approach was the key for me when I was learning to program The more I learned how other people’s programs worked the more ideas I had for my own programs All you’ll need is a computer some free software called the Python interpreter and this book Once you learn how to create the games in this book you’ll be able to develop games on your own Computers are incredible machines and learning to program them isn’t as hard as people think A computer program is a bunch of instructions that the computer can understand just like a storybook is a bunch of sentences sentences that the reader can understand To instruct a computer you write a program in a language the computer understands This book will teach you a programming language called Python There are many other program ming languages you can learn like BASIC Java JavaScript PHP and C When I was a kid I learned BASIC but newer programming languages like Python are even easier to learn Python is also used by professional programmers programmers in their work and when programming for fun Plus it’s totally free to install and use you’ll just need an internet connection to download it Because video games are nothing but computer programs they are also made up of instructions The games you’ll create from this book seem simple compared to the games for Xbox PlayStation or Nintendo These games don’t have fancy graphics because they’re meant to teach you coding basics They’re purposely simple so you can focus on learning to program Games don’t have to be complicated to be fun Who Is This Book For Programming isn’t hard but it is hard to find materials that teach you to do interesting things with programming Other computer books go over many topics most new coders don’t need This book will teach you how to program your own games you’ll learn a useful skill and have fun games to show for it This book is for (cid:120)(cid:3) Complete beginners who want to teach themselves programming even if they have no previous experience (cid:120)(cid:3) Kids and teenagers who want to learn programming by creating games (cid:120)(cid:3) Adults and teachers who wish to teach others programming (cid:120)(cid:3) Anyone young or old who wants to learn how to program by learning a professional programming language xxii Introduction
About This Book In most of the chapters in this book a single new game project is introduced introduced and explained A few of the chapters cover additional useful topics like debugging New programming concepts are explained as games make use of them and the chapters are meant to be read in order Here’s a brief rundown of what you’ll find in each chapter Chapter 1 The Interactive Shell explains how Python’s interactive shell can be used to experiment with code one line at a time Chapter 2 Writing Programs covers how to write complete programs in Python’s file editor In Chapter 3 Guess the Number you’ll program the first game in the book Guess the Number which asks the player to guess a secret number and then provides hints as to whether the guess is too high or too low In Chapter 4 A Joke-Telling Program you’ll write a simple program that tells the user several jokes In Chapter 5 Dragon Realm you’ll program a guessing game in which the player must choose between two caves one has a friendly dragon and the other has a hungry dragon Chapter 6 Using the Debugger covers how to use the debugger to fix problems in your code Chapter 7 Designing Hangman with Flowcharts explains how flowcharts flowcharts can be used to plan longer programs such as the Hangman game In Chapter 8 Writing the Hangman Code you’ll write the Hangman game following the flowchart from Chapter 7 Chapter 9 Extending Hangman extends the Hangman game with new features by making use of Python’s dictionary data type In Chapter 10 Tic-Tac-Toe you’ll learn how to write a human-versus computer Tic-Tac-Toe game that uses artificial intelligence In Chapter 11 The Bagels Deduction Game you’ll learn how to make a deduction game called Bagels in which the player must guess secret numbers based on clues Chapter 12 The Cartesian Coordinate System explains the Cartesian coordinate system which you’ll use in later games In Chapter 13 Sonar Treasure Hunt you’ll learn how to write a treasure hunting game in which the player searches the ocean for lost treasure chests In Chapter 14 Caesar Cipher you’ll create a simple encryption program program that lets you write and decode secret messages In Chapter 15 The Reversegam Game you’ll program an advanced human-versus-computer Reversi-type game that has a nearly unbeatable artificial intelligence opponent Introduction xxiii
Chapter 16 Reversegam AI Simulation expands on the Reversegam game in Chapter 15 to make multiple AIs that compete in computer versus-computer games Chapter 17 Creating Graphics introduces Python’s pygame module and shows you how to use it to draw 2D graphics Chapter 18 Animating Graphics shows you how to animate graphics with pygame In Chapter 19 Collision Detection you’ll learn how to detect when objects collide with each other in 2D games In Chapter 20 Using Sounds and Images you’ll improve your simple pygame games by adding sounds and images Chapter 21 A Dodger Game with Sounds and Images combines the concepts in Chapters 17 to 20 to make an animated game called Dodger How to Use This Book Most chapters in this book will begin with a sample run of the chapter’s featured program This sample run shows you what the program looks like when you run it The parts the user types are shown in bold I recommend that you enter the code for each program into IDLE’s file editor yourself rather than downloading or copying and pasting it You’ll remember more if you take the time to type the code Line Numbers and Indentation When typing the source code from this book do not type the line numbers at the start of each line For example if you saw the following line of code you would not need to type the 9 on the left side or the one space immediately immediately following it 9 number random randint 1 20 You’d enter only this number random randint 1 20 Those numbers are there just so this book can refer to specific lines in the program They are not part of the actual program’s source code Aside from the line numbers enter the code exactly as it appears in this book Notice that some of the lines of code are indented by four or eight or more spaces The spaces at the beginning of the line change how Python interprets instructions so they are very important to include Let’s look at an example The indented spaces here are marked with black circles so you can see them xxiv Introduction
while guesses 10 if number 42 print Hello The first line is not indented the second line is indented four spaces and the third line is indented eight spaces Although the examples in this book don’t have black circles to mark the spaces each character in IDLE is the same width so you can count the number of spaces by counting the number of characters on the line above or below Long Code Lines Some code instructions are too long to fit on one line in the book and will wrap around to the next line But the line will fit on your computer screen so type it all on one line without pressing ENTER You can tell when a new instruction starts by looking at the line numbers on the left This example has only two instructions 1 print This is the first instruction xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxx 2 print This is the second instruction not the third instruction The first instruction wraps around to a second line on the page but the second line does not have a line number so you can see that it’s still line 1 of the code Downloading and Installing Python You’ll need to install software called the Python interpreter The interpreter program understands the instructions you write in Python I’ll refer to the Python interpreter software as just Python from now on In this section I’ll show you how to download and install Python 3 specifically specifically Python 3 4 for Windows OS X or Ubuntu There are newer versions versions of Python than 3 4 but the pygame module which is used in Chapters 17 to 21 currently only supports up to 3 4 Make sure you’re using Python 3 not Python 2 Introduction xxv It’s important to know that there are some significant differences between Python 2 and Python 3 The programs in this book use Python 3 and you’ll get errors if you try to run them with Python 2 This is so important in fact that I’ve added a cartoon penguin to remind you about it On Windows download the Windows x86-64 MSI installer from https www python org downloads release python-344 and then double-click it You may have to enter the administrator password for your computer
