10. Design Patterns. The most revolutionary advance in programming since objects is the introduction of design patterns. A design pattern is a language-independent codification of a solution to a common programming problem, expressed in such a way that it can apply to many contexts. Patterns such as Singleton, Factory Method, and Visitor now find their way into daily discussions around the keyboard. This chapter shows how to implement and use some of the more useful design patterns in C++.
11. Concurrent Programming. Users have long been used to responsive user interfaces that (seem to) process multiple tasks simultaneously. Modern operating systems allow processes to have multiple threads that share the process address space. Multi-threaded programming requires a different mindset, however, and comes with its own set of «gotchas.» This chapter uses a freely available library (the ZThread library by Eric Crahen of IBM) to show how to effectively manage multi-threaded applications in C++.
Exercises
We have discovered that simple exercises are exceptionally useful during a seminar to complete a student’s understanding, so you’ll find a set at the end of each chapter.
These are fairly simple, so they can be finished in a reasonable amount of time in a classroom situation while the instructor observes, making sure all the students are absorbing the material. Some exercises are a bit more challenging to keep advanced students entertained. They’re all designed to be solved in a short time and are only there to test and polish your knowledge rather than present major challenges (presumably, you’ll find those on your own—or more likely they’ll find you).
Exercise solutions
Solutions to exercises can be found in the electronic document The C++ Annotated Solution Guide, Volume 2, available for a nominal fee from www.MindView.net.
Source code
The source code for this book is copyrighted freeware, distributed via the web site http://www.MindView.net. The copyright prevents you from republishing the code in print media without permission.
In the starting directory where you unpacked the code you will find the following copyright notice:.
//:! :CopyRight.txt
Copyright (c) MindView, Inc., 2003
Source code file from the book
«Thinking in C++, 2nd Edition, Volume 2.»
All rights reserved EXCEPT as allowed by the
following statements: You can freely use this file
for your own work (personal or commercial),
including modifications and distribution in
executable form only. Permission is granted to use
this file in classroom situations, including its
use in presentation materials, as long as the book
«Thinking in C++» is cited as the source.
Except in classroom situations, you cannot copy
and distribute this code; instead, the sole
distribution point is http://www.MindView.net
(and official mirror sites) where it is
freely available. You cannot remove this
copyright and notice. You cannot distribute
modified versions of the source code in this
package. You cannot use this file in printed
media without the express permission of the
author. The authors makes no representation about
the suitability of this software for any purpose.
It is provided «as is» without express or implied
warranty of any kind, including any implied
warranty of merchantability, fitness for a
particular purpose or non-infringement. The entire
risk as to the quality and performance of the
software is with you. The authors and publisher shall not be liable for any damages suffered by you or any third party as a result of using or distributing software. In no event will the authors or the publisher be liable for any
lost revenue, profit, or data, or for direct,
indirect, special, consequential, incidental, or
punitive damages, however caused and regardless of
the theory of liability, arising out of the use of
or inability to use software, even if Bruce Eckel
and the publisher have been advised of the
possibility of such damages. Should the software
prove defective, you assume the cost of all
necessary servicing, repair, or correction. If you
think you've found an error, please submit the
correction using the form you will find at
www.MindView.net. (Please use the same
form for non-code errors found in the book.)
///:~
You may use the code in your projects and in the classroom as long as the copyright notice is retained.
Language standards
Throughout this book, when referring to conformance to the ANSI/ISO C standard, we will be referring to the 1989 standard, and will generally just say ‘C.’ Only if it is necessary to distinguish between Standard 1989 C and older, pre-Standard versions of C will we make the distinction. We do not reference C99 in this book.
As this book goes to press the ANSI/ISO C++ committee has long ago finished working on the first C++ standard, commonly known as C++98. We will use the term Standard C++ to refer to this standardized language. If we simply refer to C++, assume we mean «Standard C++.» The C++ standards committee continues to address issues important to the C++ community that will find expression in C++0x, a future C++ standard not likely to be available for many years.
Language support
Your compiler may not support all the features discussed in this book, especially if you don’t have the newest version of your compiler. Implementing a language like C++ is a Herculean task, and you can expect that the features will appear in pieces rather than all at once. But if you attempt one of the examples in the book and get a lot of errors from the compiler, it’s not necessarily a bug in the code or the compiler—it may simply not be implemented in your particular compiler yet. On the Windows platform we have validated all examples with the C++ compiler found in Microsoft’s Visual Studio .NET 2003; Borland C++ Builder version 6; the GNU projects g++ compiler, version 3.2, running under Cygwin; and the Edison Design Group’s C++ front end using the Dinkumware full C++ library. We have also run all the examples on Mac OS X with Metrowerks C++ version 8. In those instances where a compiler does not support the feature required by a sample program, we have so indicated in comments in the source code.
Seminars, CD-ROMs & consulting
Bruce Eckel’s company, MindView, Inc., provides public hands-on training seminars based on the material in this book, and also for advanced topics. Selected material from each chapter represents a lesson, which is followed by a monitored exercise period so each student receives personal attention. We also provide on-site training, consulting, mentoring, and design & code walkthroughs. Information and sign-up forms for upcoming seminars and other contact information can be found at http://www.MindView.net.
Errors
No matter how many tricks a writer uses to detect errors, some always creep in and these often leap off the page for a fresh reader. If you discover anything you believe to be an error, please use the feedback system built into the electronic version of this book, which you will find at http://www.MindView.net. The feedback system uses unique identifiers on the paragraphs in the book, so click on the identifier next to the paragraph that you wish to comment on. Your help is appreciated.