C++ in a Nutshell

800 Pages·2003·2.201 MB·english

by  Ray Lischner

++
C
IN A NUTSHELL
Ray Lischner
C++ in a Nutshell
by Ray Lischner
Copyright © 2003 O’Reilly Media, Inc.
Printed in the United States of America.
Printing History:
May 2003: First Edition.
ISBN-10: 0-596-00298-X
ISBN-13: 978-0-596-00298-5
[M] [5/07]
Contents
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ix
1. Language Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Compilation Steps 1
Tokens 2
Comments 8
Character Sets 8
Alternative Tokens 9
Trigraphs 10
2. Declarations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Declarations and Definitions 12
Scope 14
Name Lookup 16
Linkage 22
Type Declarations 24
Object Declarations 29
Namespaces 42
3. Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Lvalues and Rvalues 50
Type Conversions 52
Constant Expressions 56
Expression Evaluation 57
Expression Rules 59
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4. Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Expression Statements 83
Declarations 84
Compound Statements 86
Selections 87
Loops 89
Control Statements 92
Handling Exceptions 94
5. Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Function Declarations 98
Function Definitions 106
Function Overloading 109
Operator Overloading 124
The main Function 130
6. Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
Class Definitions 132
Data Members 139
Member Functions 142
Inheritance 155
Access Specifiers 167
Friends 170
Nested Types 172
7. Templates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
Overview of Templates 175
Template Declarations 177
Function Templates 180
Class Templates 186
Specialization 191
Partial Specialization 194
Instantiation 195
Name Lookup 199
Tricks with Templates 205
Compiling Templates 208
8. Standard Library . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
Overview of the Standard Library 211
C Library Wrappers 215
Wide and Multibyte Characters 215
Traits and Policies 217
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Allocators 223
Numerics 225
9. Input and Output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
Introduction to I/O Streams 229
Text I/O 235
Binary I/O 237
Stream Buffers 237
Manipulators 241
Errors and Exceptions 243
10. Containers, Iterators, and Algorithms . . . . . . . . . . . . . . . . . . . . . . . . 246
Containers 246
Iterators 261
Algorithms 266
11. Preprocessor Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276
12. Language Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290
13. Library Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 327
<algorithm> 328
<bitset> 369
<cassert> 375
<cctype> 376
<cerrno> 378
<cfloat> 380
<ciso646> 384
<climits> 384
<clocale> 386
<cmath> 390
<complex> 397
<csetjmp> 406
<csignal> 407
<cstdarg> 410
<cstddef> 412
<cstdio> 413
<cstdlib> 429
<cstring> 439
<ctime> 445
<cwchar> 450
<cwctype> 465
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<deque> 470
<exception> 475
<fstream> 478
<functional> 487
<iomanip> 503
<ios> 504
<iosfwd> 523
<iostream> 525
<istream> 527
<iterator> 535
<limits> 553
<list> 558
<locale> 564
<map> 602
<memory> 613
<new> 623
<numeric> 627
<ostream> 629
<queue> 634
<set> 638
<sstream> 647
<stack> 655
<stdexcept> 657
<streambuf> 660
<string> 667
<strstream> 686
<typeinfo> 693
<utility> 695
<valarray> 698
<vector> 720
A. Compiler Extensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 729
B. Projects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 735
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 741
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 745
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Preface
C++inaNutshellisareferencetotheC++languageandlibrary.BeingaNutshell
guide,itisnotacomprehensivemanual,butitiscompleteenoughtocoverevery-
thingaworkingprofessionalneedstoknow.Nonetheless,C++issuchalargeand
complex language that even this Nutshell guide is a large book.
ThisbookcoverstheC++standard,theinternationalstandardpublishedasISO/IEC
14882:1998(E), Programming Languages—C++, plus Technical Corrigendum 1.
ManyimplementationsofC++extendthelanguageandstandardlibrary.Exceptfor
briefmentionsoflanguageandlibraryextensionsintheappendixes,thisbookcovers
only the standard. The standard library is large—it includes strings, containers,
common algorithms, and much more—but it omits much that is commonplace in
computing today: concurrency, network protocols, database access, graphics,
windows, and so on. See AppendixB for information about nonstandard libraries
that provide additional functionality.
This book is a reference. It is not a tutorial. Newcomers to C++ might find
portions of this book difficult to understand. Although each section contains
some advice on idioms and the proper use of certain language constructs, the
main focus is on the reference material. Visit http://www.tempest-sw.com/cpp/ for
links to sites and lists of books that are better suited for beginners.
Structure of This Book
Thisbookisdividedintotwointerleavedsectionsthatcoverthelanguageandthe
library,andasectionofappendixes.Roughlyspeaking,thelanguageisthepartof
C++thatdoesnotrequireanyadditional#includeheadersorfiles.Thelibraryis
the part of C++ that is declared in the standard headers.
Chapters 1–7, 11, and 12 cover the language. The first seven chapters form the
main language reference, organized by topic. It is customary for a programming
reference to contain a formal grammar, and this book does so in Chapter12,
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which is organized alphabetically by keyword (with some additional entries for
majorsyntacticcategories,suchasexpressions).Chapter11isareferenceforthe
preprocessor.
Chapter13 is the library reference, organized alphabetically by header. Chapters
8–10 present an overview of the library and introduce the topics that span indi-
vidual headers.
Sometimes,informationisduplicated,especiallyinChapter12.Mygoalhasbeen
topresentinformationwhenyouneedit,whereyouneedit.Itriedtobalancethe
need for a single, clear, complete description of each language feature with the
desire to reduce the number of cross references you must chase before you can
understand that language feature.
Here are more detailed descriptions of each chapter.
Chapter1,LanguageBasics,describesthebasicrulesfortheC++language:char-
acter sets, tokens, literals, and so on.
Chapter2, Declarations, describes how objects, types, and namespaces are
declared and how names are looked up.
Chapter3,Expressions, describes operators, precedence, and type casts.
Chapter4,Statements, describes all the C++ statements.
Chapter5, Functions, describes function declarations and definitions, overload
resolution, argument passing, and related topics.
Chapter6, Classes, describes classes (and unions and structures), members,
virtual functions, inheritance, accessibility, and multiple inheritance.
Chapter7, Templates, describes class and function template declarations, defini-
tions, instantiations, specializations, and how templates are used.
Chapter8, Standard Library, introduces the standard library and discusses some
overarching topics, such as traits and allocators.
Chapter9, Input and Output, introduces the I/O portion of the standard library.
Topics include formatted and unformatted I/O, stream buffers, and manipulators.
Chapter10, Containers, Iterators, and Algorithms, introduces the suite of
container class templates, their iterators, and generic algorithms. This is the
portion of the library that has traditionally been called the Standard Template
Library (STL).
Chapter11, Preprocessor Reference, is an alphabetical reference for the prepro-
cessor, which is part of the language, but with a distinct set of syntactic and
semantic rules.
Chapter12,LanguageReference,isanalphabeticalreferenceforthelanguageand
grammar. Backus-Naur Form (BNF) syntax descriptions are given for each
keywordandotherlanguageelements,withpointerstothefirstsevenchaptersfor
the main reference material.
Chapter13,LibraryReference,isareferencefortheentirestandardlibrary,orga-
nized alphabetically by header, and alphabetically by name within each header
section.
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AppendixA,CompilerExtensions,describeswaysthatsomecompilersextendthe
language:tosatisfycustomerneed,tomeetplatform-specificrequirements,andso
on.
AppendixB,Projects,describesafewinteresting,opensourceC++projects.You
can find information about additional projects on this book’s web site (http://
www.tempest-sw.com/cpp/).
The Glossary defines some words and phrases used throughout this book and in
the C++ community.
About the Examples
Whenever possible, the examples in this book are complete, compilable
programs. You can tell which examples fall into this category because they start
with#includedirectivesandcontainamain()function.Youcandownloadthese
examplesastextfilesfromthebook’swebsiteathttp://www.tempest-sw.com/cpp/
or from O’Reilly’s catalog page for this book: http://www.oreilly.com/catalog/
cplsian/.
Most examples are shortened to eliminate excess code that might interfere with
theclarityoftheexample.Inparticular,theseexamplesarefragmentsthatlacka
main function. Sometimes, an ellipsis indicates missing code, such as a function
body. In other cases, the omissions are clear from the context. Most abbreviated
examples have complete and compilable versions available for download.
Alloftheexampleshavebeencheckedwithseveraldifferentcompilers,including
Comeau Computing’s compiler with the Dinkumware standard library (widely
acknowledged as the most complete and correct implementations of the C++
standard). Not all compilers can compile all the examples due to limitations and
bugs in the compilers and libraries. For best results, try to work with the latest
version of your compiler. Recent releases of several major compilers have made
dramaticprogresstowardconformancewiththestandard.Whenpossible,Ihave
tried to alter the example files to work around the bugs without interfering with
the intent of the example.
I have checked all the examples with the following compilers:
Linux
• Borland Kylix 3.0
• Comeau 4.3.0.1
• GNU 3.2
• Intel 7.0
Microsoft Windows
• Borland C++ Builder 6.4
• Metrowerks CodeWarrior 8.3
• Microsoft Visual Studio.NET 7.0
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Conventions Used in This Book
This book uses the following conventions:
Constant Width
Used for identifiers and symbols, including all keywords. In the language
reference,constantwidthshowssyntaxelementsthatmustbeusedexactlyas
shown.Forexample,theifkeyword,parentheses,andelsekeywordmustbe
used exactly as follows:
if ( condition ) statement else statement
Afunctionnamethatisfollowedbyparenthesesreferstoafunctioncall,typi-
cally to obtain the function result. The function name without the
parentheses refers to the function in more general terms. For example:
Theemptyfunctionreturnstrueifthecontainerisempty,e.g.,size()==
0.
Constant Width Italic
Used in the language reference chapters for syntax elements that must be
replaced by your code. In the previous example, you must supply the
condition and the twostatements.
Constant Width Bold
Usedinexamplestohighlightkeylines,andincomplexdeclarationstohigh-
light the name being declared. In some C++ declarations, especially for
templates, the name gets buried in the middle of the declaration and can be
hard to spot.
Italic
Usedinthelanguagereferencefornonterminalsyntaxelements.Italicisalso
used for filenames, URLs, emphasis, and for the first use of a technical term.
...
Indicatesstatementsanddeclarationsthathavebeenremovedforthesakeof
brevity and clarity. An ellipsis is also a symbol in C++, but context and
comments make it clear when an ellipsis is a language element and when it
represents omitted code.
[first, last)
Indicatesarangeofvaluesfromfirsttolast,includingfirstandexcluding
last.
This icon indicates a tip, suggestion, or general note.
This icon indicates a warning or caution.
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