Aimed at advanced C++ developers who want to hone their programming chops even further, Herb Sutter's More Exceptional C++
borrows the format of his earlier title, Exceptional C++
, and delivers some of today's best available thinking on the language in a handy and effective format. A compilation of the author's own experience and research on the thornier aspects of C++, this book will serve as a worthy resource for making sure you get the most out of this powerful language.
The concise text covers a range of challenging topics in C++ without attempting to be comprehensive. Each "item" is presented as a question for you to try and solve by yourself before the author presents his solution, plus additional detail as needed. For most topics, Sutter ends by giving his advice on the best practices (and gotcha's to avoid).
Early sections concentrate on using Standard Template Library (STL) container classes, such as removing items effectively, and the subtle differences between container types. Standout sections on designing custom templates (using specialisation techniques) and designing exception-safe classes will help you do more with your own classes. One entertaining problem here shows a number-guessing game (Mastermind) built as efficiently as possible using STL code (including expert-level use of generic functions to do much of the work).
Several problems on copy-on-write (COW) semantics for more efficient classes point out the issues surrounding code optimisation. (The author argues against a simplistic approach to optimising code, including an over-reliance on inlining functions. Several times, he points out the difficulty of getting COW code to work in multi-threaded projects.)
There has been a debate in the C++ community for years on whether it's possible to design truly "exception-safe" classes. Sutter points out the difficulty with a precise analysis of the issues surrounding exceptions and C++ constructors. Material on the finer points of inheriting classes (including when to avoid and when to use multiple inheritance in C++) will extend your class design options. A good section here is the author's explication of how to simulate COM/Java style interfaces in C++, which isn't immediately obvious, even to experienced C++ developers.
Later sections delve into code-maintenance issues, including advice for using macros, typedefs and namespaces. (Advice on migrating existing C++ code into namespaces will help you combine legacy code with other libraries.) A final appendix shows off some benchmarks for optimising strings using a variety of techniques.
Intelligent, provocative and demanding, More Exceptional C++ shows off why C++ continues to be a rich, complex and challenging language. Armed with titles such as this one, experienced C++ programmers can write better code and avoid pitfalls buried in the outer edges of their favourite language. --Richard Dragan
The Greek philosopher Socrates taught by asking his students questions--questions designed to guide them and help them draw conclusions from what they already knew, and to show them how the things they were learning related to each other and to their existing knowledge. This method has become so famous that we now call it the "Socratic method." From our point of view as students, Socrates' approach involves us, makes us think, and helps us relate and apply what we already know to new information.
This book takes a page from Socrates, as did its predecessor, Exceptional C++ Sutter00. It assumes you're involved in some aspect of writing production C++ software today, and uses a question-answer format to teach you how to make effective use of standard C++ and its standard library with a particular focus on sound software engineering in modern C++. Many of the problems are drawn directly from experiences I and others have encountered while working with production C++ code. The goal of the questions is to help you draw conclusions from things you already know as well as things you've just learned, and to show how they interrelate. The puzzles will show how to reason about C++ design and programming issues--some of them common issues, some not so common; some of them plain issues, some more esoteric; and a couple because, well, just because they're fun.
This book is about all aspects of C++. I don't mean to say that it touches on every detail of C++--that would require many more pages--but rather that it draws from the wide palette of the C++ language and library features to show how apparently unrelated items can be used together to synthesize novel solutions to common problems. It also shows how apparently unrelated parts of the palette interrelate on their own, even when you don't want them to, and what to do about it. You will find material here about templates and namespaces, exceptions and inheritance, solid class design and design patterns, generic programming and macro magic--and not just as randomized tidbits, but as cohesive Items showing the interrelationships among all of these parts of modern C++.
More Exceptional C++ continues where Exceptional C++ left off. This book follows in the tradition of the first: It delivers new material, organized in bite-sized Items and grouped into themed sections. Readers of the first book will find some familiar section themes, now including new material, such as exception safety, generic programming, and memory management techniques. The two books overlap in structure and theme, not in content.
Where else does More Exceptional C++ differ? This book has a much stronger emphasis on generic programming and on using the C++ standard library effectively, including coverage of important techniques such as traits and predicates. Several Items provide in-depth looks at considerations to keep in mind when using the standard containers and algorithms; many of these considerations I've not seen covered elsewhere. There's a new section and two appendixes that focus on optimization in single- and multithreaded environments--issues that are now more than ever of practical consequence for development shops writing production code.
Versions of most Items originally appeared in Internet and magazine columns, particularly as Guru of the Week
GotW issues #31 to 62, and as print columns and articles I've written for C/C++ Users Journal
, Dr. Dobb's Journal
, the former C++ Report
, and other publications.If you don't, start with a good C++ introduction and overview. Good choices are a classic tome like Bjarne Stroustrup's The C++ Programming Language
Stroustrup00, or Stan Lippman and Josee Lajoie's C++ Primer, Third Edition
Lippman98. Next, be sure to pick up a style guide such as Scott Meyers' classic Effective C++
books Meyers96 Meyers97. I find the browser-based CD version Meyers99 convenient and useful.How to Read This Book
Each Item in this book is presented as a puzzle or problem, with an introductory header that resembles the following:Item #: The Topic of This PuzzleDifficulty:
The topic tag and difficulty rating gives you a hint of what you're in for. Note that the difficulty rating is my subjective guess at how difficult I expect most people will find each problem, so you may well find that a "7" problem is easier for you than some "5" problem. Since writing Exceptional C++, I've regularly received e-mail saying that "Item #N is easier (or harder) than that!" It's common for different people to vote "easier!" and "harder!" for the same Item. Ratings are personal; any Item's actual difficulty for you really depends on your knowledge and experience and could be easier or harder for someone else. In most cases, though, you should find the rating to be a good rule-of-thumb guide to what to expect.
You might choose to read the whole book front to back; that's great, but you don't have to. You might decide to read all the Items in a section together because you're particularly interested in that section's topic; that's cool, too. Except where there are what I call a "miniseries" of related problems which you'll see designated as "Part 1," "Part 2," and so on, the Items are pretty independent, and you should feel free to jump around, following the many cross-references among the Items in the book, as well as some references to Exceptional C++. The only guidance I'll offer is that the miniseries are designed to be read consecutively as a group; other than that, the choice is yours.
Namespaces, Typename, References, and Other Conventions
I make quite a few recommendations in this book, and I won't give you guidelines that tell you to do something I don't already do myself. That includes what I do in my own example code throughout this book. I'll also bow to existing practice and modern style, even when it really makes no material difference.
On that note, a word about namespaces: In the code examples, if you see a using-directive at file scope in one example and at function scope in another example a few pages or Items later, there's no deeper reason than that's what felt right and aesthetically pleasing to me for that particular case; for the rationale, turn to Item 40. In the narrative text itself, I've chosen to qualify standard library names with std:: when I want to emphasize that it's the standard facility I'm talking about. Once that's established, I'll generally switch back to using the unqualified name.
When it comes to declaring template parameters, I sometimes come across people who think that writing class instead of typename is old-fashioned, even though there's no functional difference between the two and the standard itself uses class most everywhere. Purely for style, and to emphasize that this book is about today's modern C++, I've switched to using typename instead of class to declare template parameters. The only exception is one place in Item 33, where I quote directly from the standard; the standard says class, so I left it in there.
Unless I call something a "complete program," it's probably not. Remember that the code examples are usually just snippets or partial programs and aren't expected to compile in isolation. You'll usually have to provide some obvious scaffolding to make a complete program out of the snippet shown.
Finally, a word about URLs: On the Web, stuff moves. In particular, stuff I have no control over moves. That makes it a real pain to publish random Web URLs in a print book lest they become out of date before the book makes it to the printer's, never mind after it's been sitting on your desk for five years.If you find that a link printed in this book no longer works, send me e-mail and tell me; I'll update that redirector to point to the new page's location (if I can find the page again) or to say that the page no longer exists (if I can't). Either way, this book's URLs will stay up-to-date despite the rigors of print media in an Internet world. Whew.
Toronto, June 2001