INTRODUCTION
Do you struggle to write programs, even though you think you understand programming languages? Are you able to read through a chapter in a programming book, nodding your head the whole way, but unable to apply what you’ve read to your own programs? Are you able to comprehend a program example you’ve read online, even to the point where you could explain to someone else what each line of the code is doing, yet you feel your brain seize up when faced with a programming task and a blank screen in your text editor?
You’re not alone. I have taught programming for over 15 years, and most of my students would have fit this description at some point in their instruction. We will call the missing skill problem solving, the ability to take a given problem description and write an original program to solve it. Not all programming requires extensive problem solving. If you’re just making minor modifications to an existing program, debugging, or adding testing code, the programming may be so mechanical in nature that your creativity is never tested. But all programs require problem solving at some point, and all good programmers can solve problems.
Problem solving is hard. It’s true that a few people make it look easy—the “naturals,” the programming world’s equivalent of a gifted athlete, like Michael Jordan. For these select few, high-level ideas are effortlessly translated into source code. To make a Java metaphor, it’s as if their brains execute Java natively, while the rest of us have to run a virtual machine, interpreting as we go.
Not being a natural isn’t fatal to becoming a programmer—if it were, the world would have few programmers. Yet I’ve seen too many worthy learners struggle too long in frustration. In the worst cases, they give up programming entirely, convinced that they can never be programmers, that the only good programmers are those born with an innate gift.
Why is learning to solve programming problems so hard?
In part, it’s because problem solving is a different activity from learning programming syntax and therefore uses a different set of mental “muscles.” Learning programming syntax, reading programs, memorizing elements of an application programming interface—these are mostly analytical “left brain” activities. Writing an original program using previously learned tools and skills is a creative “right brain” activity.
Suppose you need to remove a branch that has fallen into one of the rain gutters on your house, but your ladder isn’t quite long enough for you to reach the branch. You head into your garage and look for something, or a combination of things, that will enable you to remove the branch from the gutter. Is there some way to extend the ladder? Is there something you can hold at the top of the ladder to grab or dislodge the branch? Maybe you could just get on the roof from another place and get the branch from above. That’s problem solving, and it’s a creative activity. Believe it or not, when you design an original program, your mental process is quite similar to that of the person figuring out how to remove the branch from the gutter and quite different from that of a person debugging an existing for loop.
Most programming books, though, focus their attention on syntax and semantics. Learning the syntax and semantics of a programming language is essential, but it’s only the first step in learning how to program in that language. In essence, most programming books for beginners teach how to read a program, not how to write one. Books that do focus on writing are often effectively “cookbooks” in that they teach specific “recipes” for use in particular situations. Such books can be quite valuable as time savers, but not as a path toward learning to write original code. Think about cookbooks in the original sense. Although great cooks own cookbooks, no one who relies upon cookbooks can be a great cook. A great cook understands ingredients, preparation methods, and cooking methods and knows how they can be combined to make great meals. All a great cook needs to produce a tasty meal is a fully stocked kitchen. In the same way, a great programmer understands language syntax, application frameworks, algorithms, and software engineering principles and knows how they can be combined to make great programs. Give a great programmer a list of specifications, turn him loose with a fully stocked programming environment, and great things will happen.
In general, current programming education doesn’t offer much guidance in the area of problem solving. Instead, it’s assumed that if programmers are given access to all of the tools of programming and requested to write enough programs, eventually they will learn to write such programs and write them well. There is truth in this, but “eventually” can be a long time. The journey from initiation to enlightenment can be filled with frustration, and too many who start the journey never reach the destination.
Instead of learning by trial and error, you can learn problem solving in a systematic way. That’s what this book is all about. You can learn techniques to organize your thoughts, procedures to discover solutions, and strategies to apply to certain classes of problems. By studying these approaches, you can unlock your creativity. Make no mistake: Programming, and especially problem solving, is a creative activity. Creativity is mysterious, and no one can say exactly how the creative mind functions. Yet, if we can learn music composition, take advice on creative writing, or be shown how to paint, then we can learn to creatively solve programming problems, too. This book isn’t going to tell you precisely what to do; it’s going to help you develop your latent problem-solving abilities so that you will know what you should do. This book is about helping you become the programmer you are meant to be.
My goal is for you and every other reader of this book to learn to systematically approach every programming task and to have the confidence that you will ultimately solve a given problem. When you complete this book, I want you to think like a programmer and to believe that you are a programmer.
About This Book
Having explained the necessity of this book, I need to make a few comments about what this book is and what it is not.
Prerequisites
This book assumes you are already familiar with the basic syntax and semantics of the C++ language and that you have begun writing programs. Most of the chapters will expect you to know specific C++ fundamentals; these chapters will begin with a review of those fundamentals. If you are still absorbing language basics, don’t worry. There are plenty of great books on C++ syntax, and you can learn problem solving in parallel to learning syntax. Just make sure you have studied the relevant syntax before attempting to tackle a chapter’s problems.
Chosen Topics
The topics covered in this book represent areas in which I have most often seen new programmers struggle. They also present a broad cross-section of different areas in early and intermediate programming.
I should emphasize, however, that this is not a “cookbook” of algorithms or patterns for solving specific problems. Although later chapters discuss how to employ well-known algorithms or patterns, you should not use this book as a “crib sheet” to get you past particular problems or focus on just the chapters that directly relate to your current struggles. Instead, I would work through the entire book, skipping material only if you lack the prerequisites needed to follow the discussion.
Programming Style
A quick note here about the programming style employed in this book: This book is not about high-performance programming or running the most compact, efficient code. The style I have chosen for the source code examples is intended to be readable above all other considerations. In some cases, I take multiple steps to accomplish something that could be done in one step, just so the principle I’m trying to demonstrate is made clear.
Some aspects of programming style will be covered in this book—but larger issues, like what should or should not be included in a class, not small issues, like how code should be indented. As a developing programmer, you will of course want to employ a consistent, readable style in all of the work you do.
Exercises
The book includes a number of programming exercises. This is not a textbook, and you won’t find answers to any of the exercises in the back. The exercises provide opportunities for you to apply the concepts described in the chapters. Whether you choose to try any of the exercises is, of course, up to you, but it is essential that you put these concepts into practice. Simply reading through the book will accomplish nothing. Remember that this book is not going to tell you exactly what to do in each situation. In applying the techniques shown in this book, you will develop your own ability to discover what to do. Furthermore, growing your confidence, another primary goal of this book, requires success. In fact, that’s a good way to know when you have worked through enough exercises in a given problem area: when you are confident that you can tackle other problems in the area. Lastly, programming exercises should be fun. While there may be moments where you’d rather be doing something else, working out a programming problem should be a rewarding challenge.
You should think of this book as an obstacle course for your brain. Obstacle courses build strength, stamina, and agility and give the trainer confidence. By reading through the chapters and applying the concepts to as many exercises as you can, you’re going to build confidence and develop problem-solving skills that can be used in any programming situation. In the future, when you are faced with a difficult problem, you’ll know whether you should try going over, under, or through it.
Why C++?
The programming examples in this text are coded using C++. Having said that, this book is about solving problems with programs, not specifically about C++. You won’t find many tips and tricks specific to C++ here, and the general concepts taught throughout this book can be employed in any programming language. Nevertheless, you can’t discuss programming without discussing programs, and a specific language had to be chosen.
C++ was selected for a number of reasons. First, it’s popular in a variety of problem areas. Second, because of its origins in the strictly procedural C language, C++ code can be written using both the procedural and object-oriented paradigms. Object-oriented programming is so common now that it could not be omitted from a discussion on problem solving, but many fundamental problem-solving concepts can be discussed in strictly procedural programming terms, and doing so simplifies both the code and the discussion. Third, as a low-level language with high-level libraries, C++ allows us to discuss both levels of programming. The best programmers can “hand-wire” solutions when required and make use of high-level libraries and application programming interfaces to reduce development time. Lastly, and partly as a function of the other reasons listed, C++ is a great choice because once you have learned to solve problems in C++, you have learned to solve problems in any programming language. Many programmers have discovered how the skills learned in one language easily apply to other languages, but this is especially true for C++ because of its cross-paradigm approach and, frankly, because of its difficulty. C++ is the real deal—it’s programming without training wheels. This is daunting at first, but once you start succeeding in C++, you’ll know that you’re not going to be someone who can do a little coding—you’re going to be a programmer.