Chapter 1. About this Book

1.1 Why this Book

Soon after its introduction, C++ became a de facto standard in object-oriented programming. This led to the goal of standardization. Only by having a standard, could programs be written that would run on different platforms from PCs to mainframes. Furthermore, a standard library would enable programmers to use general components and a higher level of abstraction without losing portability, rather than having to develop all code from scratch.

The standardization process was started in 1989 by an international ANSI/ISO committee. It developed the standard based on Bjarne Stroustrup's books The C++ Programming Language and The Annotated C++ Reference Manual. After the standard was completed in 1997, several formal motions by different countries made it an international ISO and ANSI standard in 1998. The standardization process included the development of a C++ standard library. The library extends the core language to provide some general components. By using C++'s ability to program new abstract and generic types, the library provides a set of common classes and interfaces. This gives programmers a higher level of abstraction. The library provides the ability to use

All of these are supported by a fairly simple programming interface. These components are very important for many programs. These days, data processing often means inputting, computing, processing, and outputting large amounts of data, which are often strings.

The library is not self-explanatory. To use these components and to benefit from their power, you need a good introduction that explains the concepts and the important details instead of simply listing the classes and their functions. This book is written exactly for that purpose. First, it introduces the library and all of its components from a conceptional point of view. Next, it describes the details needed for practical programming. Examples are included to demonstrate the exact usage of the components. Thus, this book is a detailed introduction to the C++ library for both the beginner and the practical programmer. Armed with the data provided herein, you should be able to take full advantage of the C++ standard library.

Caveat: I don't promise that everything described is easy and self-explanatory. The library provides a lot of flexibility, but flexibility for nontrivial purposes has a price. Beware that the library has traps and pitfalls, which I point out when we encounter them and suggest ways of avoiding them.

1.2 What You Should Know Before Reading this Book

To get the most from this book you should already know C++. (The book describes the standard components of C++, but not the language itself.) You should be familiar with the concepts of classes, inheritance, templates, and exception handling. However, you don't have to know all of the minor details about the language. The important details are described in the book (the minor details about the language are more important for people who want to implement the library rather than use it). Note that the language has changed during the standardization process, so your knowledge might not be up to date. Section 2.2, provides a brief overview and introduction of the latest language features that are important for using the library. You should read this section if you are not sure whether you know all the new features of C++ (such as the keyword typename and the concept of namespaces).

1.3 Style and Structure of the Book

The C++ standard library provides different components that are somewhat but not totally independent of each other, so there is no easy way to describe each part without mentioning others. I considered several different approaches for presenting the contents of this book. One was on the order of the C++ standard. However, this is not the best way to explain the components of the C++ standard library from scratch. Another was to start with an overview of all components followed by chapters that provided more details. Alternatively, I could have sorted the components, trying to find an order that had a minimum of cross-references to other sections. My solution was to use a mixture of all three approaches. I start with a brief introduction of the general concepts and the utilities that are used by the library. Then, I describe all the components, each in one or more chapters. The first component is the standard template library (STL). There is no doubt that the STL is the most powerful, most complex, and most exciting part of the library. Its design influences other components heavily. Then I describe the more self-explanatory components, such as special containers, strings, and numeric classes. The next component discussed is one you probably know and use already: the IOStream library. It is followed by a discussion of internationalization, which had some influence on the IOStream library.

Each component description begins with the component's purpose, design, and some examples. Next, a detailed description follows that begins with different ways to use the component, as well as any traps and pitfalls associated with it. The description usually ends with a reference section, in which you can find the exact signature and definition of a component's classes and its functions.

The following is a description of the book's contents. The first four chapters introduce this book and the C++ standard library in general:

Chapters 5 through 9 describe all aspects of the STL:

Chapters 10 through 12 describe "simple" individual standard classes:

Chapters 13 and 14 deal with I/O and internationalization (two closely related subjects):

The rest of the book contains:

1.4 How to Read this Book

This book is a mix of introductory user's guide and structured reference manual regarding the C++ standard library. The individual components of the C++ standard library are independent of each other, to some extent, so after reading Chapters 2 through 4 you could read the chapters that discuss the individual components in any order. Bear in mind, that Chapter 5 through Chapter 9 all describe the same component. To understand the other STL chapters, you should start with the introduction to the STL in Chapter 5.

If you are a C++ programmer who wants to know, in general, the concepts and all parts of the library, you could simply read the book from the beginning to the end. However, you should skip the reference sections. To program with certain components of the C++ standard library, the best way to find something is to use the index. I have tried to make the index very comprehensive to save you time when you are looking for something.

In my experience, the best way to learn something new is to look at examples. Therefore, you'll find a lot of examples throughout the book. They may be a few lines of code or complete programs. In the latter case, you'll find the name of the file containing the program as the first comment line. You can find the files on the Internet at my Web site at

1.5 State of the Art

While I was writing this book, the C++ standard was completed. Please bear in mind that some compilers might not yet confirm to it. This will most likely change in the near future. As a consequence, you might discover that not all things covered in this book work as described on your system, and you may have to change example programs to fit your specific environment. I can compile almost all example programs with version 2.8 or higher of the EGCS compiler, which is free for almost all platforms and available on the Internet (see and on several software CDs.

1.6 Example Code and Additional Information

You can access all example programs and acquire more informations about this book and the C++ standard library from my Web site at Also, you can find a lot of additional information about this topic on the Internet. See Internet Resources for details.

1.7 Feedback

I welcome your feedback (good and bad) on this book. I tried to prepare it carefully; however, I'm human, and at some time I have to stop writing and tweaking. So, you may find some errors, inconsistencies, or subjects that could be described better. Your feedback will give me the chance to improve later editions. The best way to reach me is by Email:

You can also reach me by phone, fax, or "snail" mail:

Nicolai M. Josuttis

Berggarten 9

D-38108 Braunschweig


Phone: +49 5309 574

Fax: +49 5309 5774

Many thanks.

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