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an Introduction to programming in threads

This book teaches how to write GUI applications using the Python programming language and the Qt application development framework. The only essential prior knowledge is that you can program in some object-oriented programming language, such as C++, C#, Java, or of course, Python itself. For the rich text chapter, some familiarity with HTML and with regular expressions is assumed,and the databases and threading chapters assume some basic knowledge of those topics. A knowledge of GUI programming is not required, since all the key concepts are covered. The book will be useful to people who program professionally as part of their job, whether as full-time software developers, or those from other disciplines, including scientists and engineers, who need to do some programming in support of their work. It is also suitable for undergraduate and post-graduate students, particularly those doing courses or research that includes a substantial computing element. The exercises (with solutions) are provided especially to help students. Python is probably the easiest to learn and nicest scripting language in widespread use,and Qt is probably the best library for developing GUI applications. The combination of Python and Qt, “PyQt”, makes it possible to develop applications on any supported platform and run them unchanged on all the supported platforms—for example, all modern versions of Windows, Linux, Mac OS X, and most Unix-based systems. No compilation is required thanks to Python being interpreted, and no source code changes to adapt to different operating systems are required thanks to Qt abstracting away the platformspecific details. We only have to copy the source file or files to a target machine that has both Python and PyQt installed and the application will run. If you are new to Python:Welcome! You are about to discover a language that is clear to read and write, and that is concise without being cryptic. Python supports many programming paradigms, but because our focus is on GUI programming, we will take an object-oriented approach everywhere except in the very early chapters.

1.1 Introduction Credit: David Ascher, ActiveState, co-author of Learning Python (O'Reilly) Programming languages are like natural languages. Each has a set of qualities that polyglots generally agree on as characteristics of the language. Russian and French are often admired for their lyricism, while English is more often cited for its precision and dynamism: unlike the Académie-defined French language, the English language routinely grows words to suit its speakers' needs, such as "carjacking," "earwitness," "snail mail," "email," "googlewhacking," and "blogging." In the world of computer languages, Perl is well known for its many degrees of freedom: TMTOWTDI (There's More Than One Way To Do It) is one of the mantras of the Perl programmer. Conciseness is also seen as a strong virtue in the Perl and APL communities. In contrast, as you'll see in many of the discussions of recipes throughout this volume, Python programmers often express their belief in the value of clarity and elegance. As a well-known Perl hacker once said, Python's prettier, but Perl is more fun. I agree with him that Python does have a strong (as in well-defined) aesthetic, while Perl has more of a sense of humor. I still have more fun coding in Python, though. The reason I bring up these seemingly irrelevant bits at the beginning of this book is that the recipes you see in this first chapter are directly related to Python's aesthetic and social dynamics. In most of the recipes in this chapter, the author presents a single elegant language feature, but one that he feels is underappreciated. Much like I, a proud resident of Vancouver, will go out of my way to show tourists the really neat things about the city, from the parks to the beaches to the mountains, a Python user will seek out friends and colleagues and say, "You gotta see this!" Programming in Python, in my mind, is a shared social pleasure, not all that competitive. There's great pleasure in learning a new feature and appreciating its design, elegance, and judicious use, and there's a twin pleasure in teaching another or another thousand about that feature. When we identified the recipe categories for this collection, our driving notion was that there would be recipes of various kinds, each aiming to achieve something specific梐 souffle recipe, a tart recipe, an osso buco recipe. Those would naturally bunch into fairly typical categories, such as desserts, appetizers, and meat dishes, or their perhaps less appetizing, nonmetaphorical equivalents, such as files, algorithms, and so on. So we picked a list of categories, added the categories to the Zope site used to collect recipes, and opened the floodgates. Pretty soon, it became clear that some submissions were really hard to fit into the predetermined categories. These recipes are the Pythonic equivalent of making a roux (melted butter or fat combined with flour, used in sauce-making, for those of you without an Italian sauce background), kneading dough, flouring, flipping a pan's contents, blanching, and the myriad other tricks that any accomplished cook knows, but that you won't find in any "straight" recipe book. Many of these tricks and techniques are used in preparing various kinds of meals, but it's hard to pigeonhole them as relevant for a given type of dish. And if you're a novice cook looking up a fancy recipe, you're likely to get frustrated quickly, as these techniques are typically found only in books like Cooking for Divorced Middle-Aged Men. We didn't want to exclude this precious category from this book, so a new category was born. That explains why this chapter exists. This chapter is pretty flimsy, though, in that while the title refers to shortcuts, there is nothing here like what one could have expected had the language in question been Python's venerable cousin, Perl. If this had been a community-authored Perl cookbook, entries in this category would probably have outnumbered those in most other chapters. That is because Perl's syntax provides, proudly, many ways to do pretty much anything. Furthermore, each way is "tricky" in a good way: the writer gets a little thrill out of exploiting an odd corner of the language. That chapter would be impressive, and competitive, and fun. Python programmers just don't get to have that kind of fun on that kind of scale (by which I mean the scale of syntactic shortcuts and semantic-edge cases). No one gives multi-hour talks about tricks of the Python grand masters... Python grand masters simply don't have that many frequently used tricks up their sleeves!

Writing programs gives you the power to control your PC. Almost everyone knows how to use a computer, but few people take the next step and learn how to control it. If you use other people’s software, you will always be limited by what other people think you want to do. Write your own programs and the only limit will be your own imagination. Programming will make you more creative, it will make you think more precisely, and it will teach you to analyze and solve problems logically. Do you want to be programmed or be the programmer?

Introduction to Algorithms Prof. Charles E. Leiserson The theoretical study of computer-program performance and resource usage. What’s more important than performance? • modularity • correctness • maintainability • functionality • robustness • user-friendliness • programmer time • simplicity • extensibility • reliability

This book is a thorough rewrite of the first edition to reflect all the changes introduced in C++ by the finalization of the ANSI/ISO C++ Standard. The entire text present in the first edition has been examined and rewritten, sometimes removing old examples, often changing existing examples and adding new ones, and adding many new exercises. Significant rearrangement and re-ordering of the material took place to reflect the availability of better tools and my improved understanding of how people learn C++. A new chapter was added which is a rapid introduction to the C concepts and basic C++ features for those who haven’t been exposed. The CD ROM bound into the back of the book contains a seminar which is an even gentler introduction to the C concepts necessary to understand C++ (or Java). It was created by Chuck Allison for my company (MindView, Inc.) and it’s called “Thinking in C: Foundations for Java and C++.” It introduces you to the aspects...

This book is a thorough rewrite of the first edition to reflect all of the changes introduced in C++ by the finalization of the C++ Standard, and also to reflect what I’ve learned since writing the first edition. The entire text present in the first edition has been examined and rewritten, sometimes removing old examples, often changing existing examples and adding new ones, and adding many new exercises. Significant rearrangement and re-ordering of the material took place to reflect the availability of better tools and my improved understanding of how people learn C++. A new chapter was added which is a rapid introduction to the C concepts and basic C++ features for those who don’t have the C background to tackle the rest of the book. The CD ROM bound into the back of the book contains a seminar that is an even gentler introduction to the C concepts necessary to understand C++ (or Java...

As the Internet continues to evolve, so too does the necessity for a language that addresses the functionality needs of the Internet’s web viewers. Over time, some programming languages have come and gone, and others have continued to evolve. Several languages have moved into the lead in the race for supremacy. Although languages such as ColdFusion,ASP.NET, and CGI certainly have their advantages, PHP seems to be the developer’s choice for a versatile, open-source solution.PHP has grown over the years and, thanks to its devotees, has continued to adopt the functionality most preferred by its user base. By actually listening to the developers to help guide PHP’s development path, the PHP creators have introduced some impressive functionality over the years. However, PHP 4, while a sound developmental language and tool, was lacking on a few fronts. For instance, it had a means for developers to take an object-oriented approach, but several key pieces of functionality were not implemented, such as exception handling and session support (for objects). PHP 5 has changed all that. No longer must developers write classes that are missing functionality. Available to PHP is a full set of object-oriented development tools. Of particular note in PHP 5 is the ability to protect class variables in several ways. In addition, inheritance difficulties are now a thing of the past, and exception handling has become a nice way of taking care of pesky errors and validation.....

计算机网络第四版的全部答案，英文版 for example: 1.The dog can carry 21 gigabytes, or 168 gigabits. A speed of 18 km/hour equals 0.005 km/sec. The time to travel distance x km is x /0.005 = 200x sec, yielding a data rate of 168/200x Gbps or 840/x Mbps. For x < 5.6 km, the dog has a higher rate than the communication line.....

Linux是一套免费使用和自由传播的类Unix操作系统，它主要用于基于Intel x8 6系列CPU的计算机上。这个系统是由全世界各地的成千上万的程序员设计和实现的。其目的是建立不受任何商品化软件的版权制约的、全世界都能自由使用的Unix兼容产品。 　　　Linux的出现，最早开始于一位名叫Linus Torvalds的计算机业余爱好者，当时他是芬兰赫尔辛基大学的学生。他的目的是想设计一个代替Minix（是由一位名叫Andrew Tannebaum的计算机教授编写的一个操作系统示教程序）的操作系统，这个操作系统可用于386、486或奔腾处理器的个人计算机上，并且具有 Unix操作系统的全部功能，因而开始了Linux雏形的设计。 　　　Linux以它的高效性和灵活性著称。它能够在PC计算机上实现全部的Unix特性，具有多任务、多用户的能力。Linux是在GNU公共许可权限下免费获得的，是一个符合POSIX标准的操作系统。Linux操作系统软件包不仅包括完整的Linux操作系统，而且还包括了文本编辑器、高级语言编译器等应用软件。它还包括带有多个窗口管理器的X-Windows图形用户界面，如同我们使用Windows NT一样，允许我们使用窗口、图标和菜单对系统进行操作。 　　　Linux之所以受到广大计算机爱好者的喜爱，主要原因有两个，一是它属于自由软件，用户不用支付任何费用就可以获得它和它的源代码，并且可以根据自己的需要对它进行必要的修改，无偿对它使用，无约束地继续传播。另一个原因是，它具有Unix的全部功能，任何使用Unix操作系统或想要学习Unix操作系统的人都可以从Linux中获益

关于Mathematica的基础教程，翻译版，科学出版社，是全美经典学习指导系列丛书之一

摘自计算机网络原理书（前言）： This book is now in its fourth edition. Each edition has corresponded to a different phase in the way computer networks were used. When the first edition appeared in 1980, networks were an academic curiosity. When the second edition appeared in 1988, networks were used by universities and large businesses. When the third edition appeared in 1996, computer networks, especially the Internet, had become a daily reality for millions of people. The new item in the fourth edition is the rapid growth of wireless networking in many forms. The networking picture has changed radically since the third edition. In the mid-1990s, numerous kinds of LANs and WANs existed, along with multiple protocol stacks. By 2003, the only wired LAN in widespread use was Ethernet, and virtually all WANs were on the Internet. Accordingly, a large amount of material about these older networks has been removed. However, new developments are also plentiful. The most important is the huge increase in wireless networks, including 802.11, wireless local loops, 2G and 3G cellular networks, Bluetooth, WAP, i-mode, and others. Accordingly, a large amount of material has been added on wireless networks. Another newly-important topic is security, so a whole chapter on it has been added.

A pretty good book about compiler