Herbert schildt the complete reference c++

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The Complete Reference

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abc

Contents at a Glance

Part I The Foundation of C++: The C Subset

1 An Overview of C 3

2 Expressions 13

3 Statements 57

4 Arrays and Null-Terminated Strings 89

5 Pointers 113

6 Functions 137

7 Structures, Unions, Enumerations, and User-Defined Types 161

8 C-Style Console I/O 187

9 File I/O 211

10 The Preprocessor and Comments 237

Part II C++ 11 An Overview of C++ 255

12 Classes and Objects 289

13 Arrays, Pointers, References and the Dynamic Allocation Operators 327

14 Function Overloading, Copy Constructors, and Default Arguments 361

15 Operator Overloading 385

v

16 Inheritance 419

17 Virtual Functions and Polymorphism 445

18 Templates 461

19 Exception Handling 489

20 C++ I/O System Basics 511

21 C++ File I/O 541

22 Run-Time Type ID and the Casting Operators 569

23 Namespaces, Conversion Functions,and Other Advanced Topics 593

24 Introducing the Standard Template Library 625

Part III The Standard Function Library 25 The C-Based I/O Functions 695

26 The String and Character Functions 719

27 The Mathematical Functions 733

28 Time, Date, and Localization Functions 743

29 The Dynamic Allocation Functions 753

30 Utility Functions 757

31 The Wide-Character Functions 771

Part IV The Standard C++ Class Library 32 The Standard C++ I/O Classes 783

33 The STL Container Classes 807

34 The STL Algorithms 835

35 STL Iterators, Allocators, and Function Objects 857

36 The String Class 877

37 The Numeric Classes 893

38 Exception Handling and Miscellaneous Classes 921

Part V Applying C++ 39 Integrating New Classes: A Custom String Class 931

40 An Object-Oriented Expression Parser 959

Index 995

Preface xxix

Part I The Foundation of C++: The C Subset 1 An Overview of C 3

The Origins of C 4

C Is a Middle-Level Language 4

C Is a Structured Language 6

C Is a Programmer's Language 8

The Form of a C Program 9

The Library and Linking 10

Separate Compilation 12

Understanding the C and CPP File Extensions 12

2 Expressions 13

The Five Basic Data Types 14

vii

Modifying the Basic Types 15

Identifier Names 16

Variables 17

Where Variables Are Declared 17

Local Variables 17

Formal Parameters 21

Global Variables 21

Access Modifiers 23

const 23

volatile 24

Storage Class Specifiers 25

extern 25

static Variables 27

register Variables 29

Variable Initializations 31

Constants 31

Hexadecimal and Octal Constants 32

String Constants 33

Backslash Character Constants 33

Operators 34

The Assignment Operator 34

Type Conversion in Assignments 35

Multiple Assignments 36

Arithmetic Operators 37

Increment and Decrement 37

Relational and Logical Operators 39

Bitwise Operators 42

The ? Operator 47

The & and * Pointer Operators 47

The Compile-Time Operator sizeof 49

The Comma Operator 50

The Dot (.) and Arrow (−>) Operators 51

The [ ] and ( ) Operators 51

Precedence Summary 52

Expressions 53

Order of Evaluation 53

Type Conversion in Expressions 53

Casts 54

Spacing and Parentheses 55

Shorthand Assignments 56

3 Statements 57

True and False in C and C++ 58

Selection Statements 59

if 59

Nested ifs 60

The if-else-if Ladder 62

The ? Alternative 63

The Conditional Expression 66

switch 67

Nested switch Statements 70

Iteration Statements 70

The for Loop 70

for Loop Variations 72

The Infinite Loop 76

for Loops with No Bodies 77

The while Loop 77

The do-while Loop 79

Declaring Variables within Selection and Iteration Statements 81

Jump Statements 82

The return Statement 82

The goto Statement 83

The break Statement 83

The exit( ) Function 85

The continue Statement 86

Expression Statements 88

Block Statements 88

4 Arrays and Null-Terminated Strings 89

Single-Dimension Arrays 90

Generating a Pointer to an Array 92

Passing Single-Dimension Arrays to Functions 92

Null-Terminated Strings 94

Two-Dimensional Arrays 96

Arrays of Strings 100

Multidimensional Arrays 101

Indexing Pointers 102

Array Initialization 105

Unsized Array Initializations 106

A Tic-Tac-Toe Example 108

5 Pointers 113

What Are Pointers? 114

Pointer Variables 115

The Pointer Operators 115

Pointer Expressions 116

Pointer Assignments 117

Pointer Arithmetic 117

Pointer Comparisons 119

Pointers and Arrays 120

Arrays of Pointers 122

Multiple Indirection 123

Initializing Pointers 124

Pointers to Functions 126

C's Dynamic Allocation Functions 129

Problems with Pointers 131

6 Functions 137

The General Form of a Function 138

Scope Rules of Functions 138

Function Arguments 139

Call by Value, Call by Reference 139

Creating a Call by Reference 140

Calling Functions with Arrays 142

argc and argv—Arguments to main( ) 144

The return Statement 147

Returning from a Function 147

Returning Values 149

Returning Pointers 151

Functions of Type void 152

What Does main( ) Return? 153

Recursion 153

Function Prototypes 155

Standard Library Function Prototypes 157

Declaring Variable-Length Parameter Lists 158

Old-Style Versus Modern Function Parameter Declarations 158

Implementation Issues 159

Parameters and General-Purpose Functions 159

Efficiency 159

7 Structures, Unions, Enumerations, and User-Defined Types 161

Structures 162

Accessing Structure Members 165

Structure Assignments 165

Arrays of Structures 166

Passing Structures to Functions 166

Passing Structure Members to Functions 167

Passing Entire Structures to Functions 167

Structure Pointers 169

Declaring a Structure Pointer 170

Using Structure Pointers 170

Arrays and Structures Within Structures 173

Bit-Fields 174

Unions 176

Enumerations 180

Using sizeof to Ensure Portability 183

typedef 184

8 C-Style Console I/O 187

An Important Application Note 188

Reading and Writing Characters 189

A Problem with getchar( ) 190

Alternatives to getchar( ) 190

Reading and Writing Strings 192

Formatted Console I/O 195

printf( ) 195

Printing Characters 196

Printing Numbers 196

Displaying an Address 198

The %n Specifier 198

Format Modifiers 199

The Minimum Field Width Specifier 199

The Precision Specifier 200

Justifying Output 201

Handling Other Data Types 202

The * and # Modifiers 202

scanf( ) 203

Format Specifiers 203

Inputting Numbers 203

Inputting Unsigned Integers 205

Reading Individual Characters Using scanf( ) 205

Reading Strings 205

Inputting an Address 206

The %n Specifier 206

Using a Scanset 206

Discarding Unwanted White Space 207

Non-White-Space Characters in the Control String 208

You Must Pass scanf( ) Addresses 208

Format Modifiers 208

Suppressing Input 209

9 File I/O 211

C Versus C++ File I/O 212

Streams and Files 212

Streams 212

Text Streams 213

Binary Streams 213

Files 213

File System Basics 214

The File Pointer 215

Opening a File 215

Closing a File 217

Writing a Character 218

Reading a Character 218

Using fopen( ), getc( ), putc( ), and fclose( ) 218

Using feof( ) 220

Working with Strings: fputs( ) and fgets( ) 222

rewind( ) 223

ferror( ) 224

Erasing Files 226

Flushing a Stream 227

fread( ) and fwrite( ) 227

Using fread( ) and fwrite( ) 228

fseek( ) and Random-Access I/O 229

fprintf( ) and fscanf( ) 231

The Standard Streams 232

The Console I/O Connection 234

Using freopen( ) to Redirect the Standard Streams 235

10 The Preprocessor and Comments 237

The Preprocessor 238

#define 238

Defining Function-like Macros 240

#error 241

#include 242

Conditional Compilation Directives 242

#if, #else, #elif, and #endif 243

#ifdef and #ifndef 245

#undef 246

Using defined 247

#line 248

#pragma 248

The # and ## Preprocessor Operators 248

Predefined Macro Names 250

C-Style Comments 250

Part II C++ 11 An Overview of C++ 255

The Origins of C++ 256

What Is Object-Oriented Programming? 257

Encapsulation 258

Polymorphism 258

Inheritance 259

Some C++ Fundamentals 259

A Sample C++ Program 260

A Closer Look at the I/O Operators 263

Declaring Local Variables 264

No Default to int 265

The bool Data Type 266

Old-Style vs Modern C++ 266

The New C++ Headers 268

Namespaces 269

Working with an Old Compiler 270

Introducing C++ Classes 270

Function Overloading 274

Operator Overloading 278

Inheritance 278

Constructors and Destructors 283

The C++ Keywords 287

The General Form of a C++ Program 288

12 Classes and Objects 289

Classes 290

Structures and Classes Are Related 293

Unions and Classes Are Related 295

Anonymous Unions 297

Friend Functions 298

Friend Classes 302

Inline Functions 303

Defining Inline Functions Within a Class 306

Parameterized Constructors 307

Constructors with One Parameter: A Special Case 309

Static Class Members 310

Static Data Members 310

Static Member Functions 315

When Constructors and Destructors Are Executed 317

The Scope Resolution Operator 319

Nested Classes 320

Local Classes 320

Passing Objects to Functions 321

Returning Objects 323

Object Assignment 324

13 Arrays, Pointers, References, and the Dynamic Allocation Operators 327

Arrays of Objects 328

Creating Initialized vs Uninitialized Arrays 330

Pointers to Objects 331

Type Checking C++ Pointers 333

The this Pointer 334

Pointers to Derived Types 336

Pointers to Class Members 339

References 341

Reference Parameters 341

Passing References to Objects 345

Returning References 346

Independent References 347

References to Derived Types 348

Restrictions to References 349

A Matter of Style 349

C++'s Dynamic Allocation Operators 349

Initializing Allocated Memory 351

Allocating Arrays 352

Allocating Objects 353

The nothrow Alternative 358

The Placement Forms of new and delete 359

14 Function Overloading, Copy Constructors, and Default Arguments 361

Function Overloading 362

Overloading Constructor Functions 364

Overloading a Constructor to Gain Flexibility 364

Allowing Both Initialized and Uninitialized Objects 366

Copy Constructors 368

Finding the Address of an Overloaded Function 372

The overload Anachronism 373

Default Function Arguments 374

Default Arguments vs Overloading 378

Using Default Arguments Correctly 380

Function Overloading and Ambiguity 380

15 Operator Overloading 385

Creating a Member Operator Function 386

Creating Prefix and Postfix Forms of the Increment and Decrement Operators 391

Overloading the Shorthand Operators 392

Operator Overloading Restrictions 392

Operator Overloading Using a Friend Function 393

Using a Friend to Overload ++ or – – 395

Friend Operator Functions Add Flexibility 398

Overloading new and delete 400

Overloading new and delete for Arrays 405

Overloading the nothrow Version of new and delete 408

Overloading Some Special Operators 409

Overloading [ ] 409

Overloading ( ) 413

Overloading –> 415

Overloading the Comma Operator 416

16 Inheritance 419

Base-Class Access Control 420

Inheritance and protected Members 422

Protected Base-Class Inheritance 426

Inheriting Multiple Base Classes 427

Constructors, Destructors, and Inheritance 428

When Constructor and Destructor Functions Are Executed 428

Passing Parameters to Base-Class Constructors 432

Granting Access 436

Virtual Base Classes 439

17 Virtual Functions and Polymorphism 445

Virtual Functions 446

Calling a Virtual Function Through a Base Class Reference 449

The Virtual Attribute Is Inherited 450

Virtual Functions Are Hierarchical 452

Pure Virtual Functions 455

Abstract Classes 457

Using Virtual Functions 457

Early vs Late Binding 460

18 Templates 461

Generic Functions 462

A Function with Two Generic Types 465

Explicitly Overloading a Generic Function 465

Overloading a Function Template 468

Using Standard Parameters with Template Functions 468

Generic Function Restrictions 469

Applying Generic Functions 470

A Generic Sort 471

Compacting an Array 472

Generic Classes 474

An Example with Two Generic Data Types 478

Applying Template Classes: A Generic Array Class 479

Using Non-Type Arguments with Generic Classes 481

Using Default Arguments with Template Classes 483

Explicit Class Specializations 485

The typename and export Keywords 486

The Power of Templates 487

19 Exception Handling 489

Exception Handling Fundamentals 490

Catching Class Types 496

Using Multiple catch Statements 497

Handling Derived-Class Exceptions 499

Exception Handling Options 500

Catching All Exceptions 500

Restricting Exceptions 502

Rethrowing an Exception 504

Understanding terminate( ) and unexpected( ) 505

Setting the Terminate and Unexpected Handlers 506

The uncaught_exception( ) Function 507

The exception and bad_exception Classes 508

Applying Exception Handling 508

20 The C++ I/O System Basics 511

Old vs Modern C++ I/O 512

C++ Streams 513

The C++ Stream Classes 513

C++'s Predefined Streams 514

Formatted I/O 515

Formatting Using the ios Members 515

Setting the Format Flags 516

Clearing Format Flags 517

An Overloaded Form of setf( ) 518

Examining the Formatting Flags 520

Setting All Flags 521

Using width( ), precision( ), and fill( ) 522

Using Manipulators to Format I/O 524

Overloading << and >> 528

Creating Your Own Inserters 528

Creating Your Own Extractors 534

Creating Your Own Manipulator Functions 537

21 C++ File I/O 541

<fstream> and the File Classes 542

Opening and Closing a File 542

Reading and Writing Text Files 545

Unformatted and Binary I/O 547

Characters vs Bytes 547

put( ) and get( ) 548

read( ) and write( ) 550

More get( ) Functions 553

getline( ) 553

Detecting EOF 555

The ignore( ) Function 557

peek( ) and putback( ) 558

flush( ) 558

Random Access 559

Obtaining the Current File Position 563

I/O Status 563

Customized I/O and Files 565

22 Run-Time Type ID and the Casting Operators 569

Run-Time Type Identification (RTTI) 570

A Simple Application of Run-Time Type ID 576

typeid Can Be Applied to Template Classes 578

The Casting Operators 580

dynamic_cast 580

Replacing typeid with dynamic_cast 584

Using dynamic_cast with Template Classes 586

const_cast 588

static_cast 590

reinterpret_cast 590

23 Namespaces, Conversion Functions,

and Other Advanced Topics 593

Namespaces 594

Namespace Fundamentals 594

using 598

Unnamed Namespaces 600

Some Namespace Options 601

The std Namespace 603

Creating Conversion Functions 605

const Member Functions and mutable 609

Volatile Member Functions 611

Explicit Constructors 612

Using the asm Keyword 613

Linkage Specification 614

Array-Based I/O 615

The Array-Based Classes 616

Creating an Array-Based Output Stream 616

Using an Array as Input 618

Input/Output Array-Based Streams 620

Using Dynamic Arrays 621

Using Binary I/O with Array-Based Streams 622

Summarizing the Differences Between C and C++ 623

24 Introducing the Standard Template Library 625

An Overview of the STL 626

Containers 626

Algorithms 627

Iterators 627

Other STL Elements 628

The Container Classes 629

General Theory of Operation 630

Vectors 631

Accessing a Vector Through an Iterator 635

Inserting and Deleting Elements in a Vector 637

Storing Class Objects in a Vector 639

Lists 641

Understanding end( ) 645

push_front( ) vs push_back( ) 647

Sort a List 648

Merging One List with Another 649

Storing Class Objects in a List 651

Maps 654

Storing Class Objects In a Map 658

Algorithms 660

Counting 660

Removing and Replacing Elements 666

Reversing a Sequence 668

Transforming a Sequence 669

Using Function Objects 671

Unary and Binary Function Objects 671

Using the Built-in Function Objects 671

Creating a Function Object 674

Using Binders 676

The string Class 679

Some string Member Functions 683

Strings Are Containers 689

Putting Strings into Other Containers 690

Final Thoughts on the STL 691

Part III The Standard Function Library 25 The C-Based I/O Functions 695

clearerr 696

fclose 697

feof 697

ferror 697

fflush 698

fgetc 698

fgetpos 698

fgets 699

fopen 699

fprintf 701

fputc 701

fputs 702

fread 702

freopen 702

fscanf 703

fseek 703

fsetpos 704

ftell 704

fwrite 705

getc 705

getchar 706

gets 706

perror 706

printf 707

putc 710

putchar 710

puts 710

remove 711

rename 711

rewind 711

scanf 711

setbuf 715

setvbuf 715

sprintf 716

sscanf 716

tmpfile 716

tmpnam 717

ungetc 717

vprintf, vfprintf, and vsprintf 718

26 The String and Character Functions 719

isalnum 720

isalpha 720

iscntrl 721

isdigit 721

isgraph 721

islower 721

isprint 722

ispunct 722

isspace 722

isupper 723

isxdigit 723

memchr 723

memcmp 723

memcpy 724

memmove 724

memset 725

strcat 725

strchr 725

strcmp 726

strcoll 726

strcpy 727

strcspn 727

strerror 727

strlen 727

localtime 748mktime 748setlocale 748strftime 749time 750

29 The Dynamic Allocation Functions 753

calloc 754free 754malloc 755realloc 755

30 Utility Functions 757

abort 758abs 758assert 759atexit 759atof 759atoi 760atol 760bsearch 760div 761exit 762getenv 762labs 762ldiv 763longjmp 763mblen 763mbstowcs 764mbtowc 764qsort 764raise 765rand 766setjmp 766signal 766srand 767strtod 767strtol 768strtoul 768system 769va_arg, va_start, and va_end 769wcstombs 770wctomb 770

31 The Wide-Character Functions 771

The Wide-Character Classification Functions 772

The Wide-Character I/O Functions 775

The Wide-Character String Functions 775

Wide-Character String Conversion Functions 775

Wide-Character Array Functions 778

Multibyte/Wide-Character Conversion Functions 779

Part IVThe Standard C++ Class Library

32 The Standard C++ I/O Classes 783

The I/O Classes 784

The I/O Headers 786

The Format Flags and I/O Manipulators 787

Several Data Types 789

The streamsize and streamoff Types 789

The streampos and wstreampos Types 789

The pos_type and off_type Types 789

The openmode Type 789

The iostate Type 790

The seekdir type 790

The failure Class 790

Overload << and >> Operators 790

The General-Purpose I/O Functions 791

put 798putback 798rdstate 798read 799readsome 799seekg and seekp 800setf 801setstate 801str 802stringstream, istringstream, ostringstream 802sync_with_stdio 803tellg and tellp 804unsetf 804width 804write 805

33 The STL Container Classes 807

The Container Classes 808

bitset 810deque 812list 815map 818multimap 820multiset 823queue 825priority_queue 826set 827stack 829vector 830

34 The STL Algorithms 835

adjacent_find 836binary_search 836copy 837copy_backward 837count 837count_if 838equal 838equal_range 838fill and fill_n 839find 839find_end 839find_first_of 839

remove, remove_if, remove_copy, and remove_copy_if 848

replace, replace_copy, replace_if, and replace_copy_if 848

reverse and reverse_copy 849

rotate and rotate_copy 849

35 STL Iterators, Allocators, and Function Objects 857

Iterators 858

The Basic Iterator Types 858The Low-Level Iterator Classes 859The Predefined Iterators 860Two Iterator Functions 868Function Objects 868

Function Objects 869Binders 870Negators 871Adaptors 872Allocators 875

36 The String Class 877

The basic_string Class 878The char_traits Class 890

37 The Numeric Classes 893

The complex Class 894The valarray Class 898

The slice and gslice Classes 913The Helper Classes 916The Numeric Algorithms 916

accumulate 916adjacent_difference 917inner_product 918partial_sum 919

38 Exception Handling and Miscellaneous Classes 921

Exceptions 922

<exception> 922

<stdexcept> 923auto_ptr 924The pair Class 926Localization 927Other Classes of Interest 927

Part VApplying C++

39 Integrating New Classes: A Custom String Class 931

The StrType Class 932

The Constructor and Destructor Functions 934

I/O on Strings 935

The Assignment Functions 937

Concatenation 938

Substring Subtraction 941

The Relational Operators 943

Miscellaneous String Functions 944

The Entire StrType Class 945

Using the StrType Class 954

Creating and Integrating New Types in General 957

A Simple Expression Parser 967

Understanding the Parser 973

Adding Variables to the Parser 974

Syntax Checking in a Recursive-Descent Parser 984

Building a Generic Parser 985

Some Things to Try 993

Index 995

This is the third edition of C++: The Complete Reference In the years that have transpired

since the second edition, C++ has undergone many changes Perhaps the most important

is that it is now a standardized language In November of 1997, the ANSI/ISO

committee charged with the task of standardizing C++, passed out of committee anInternational Standard for C++ This event marked the end of a very long, and attimes contentious, process As a member of the ANSI/ISO C++ committee, I watchedthe progress of the emerging standard, following each debate and argument Near theend, there was a world-wide, daily dialogue, conducted via e-mail, in which the prosand cons of this or that issue were put forth, and finally resolved While the processwas longer and more exhausting than anyone at first envisioned, the result was worththe trouble We now have a standard for what is, without question, the most importantprogramming language in the world

During standardization, several new features were added to C++ Some are

relatively small Others, like the STL (Standard Template Library) have ramificationsthat will affect the course of programming for years to come The net effect of theadditions was that the scope and range of the language were greatly expanded Forexample, because of the addition of the numerics library, C++ can be more convenientlyused for numeric processing Of course, the information contained in this edition

xxix

reflects the International Standard for C++ defined by the ANSI/ISO committee,including its new features.

What's New in the Third Edition

The third edition of C++: The Complete Reference is greatly expanded beyond its

predecessor In fact, the length of the book has nearly doubled! The main reason forthis is that the third edition now includes comprehensive coverage of both the standardfunction library and the standard class library Neither of these were sufficiently welldefined when the second edition was being prepared to warrant inclusion With thestandardization of C++ being complete, these topics can finally be added

Aside from these major additions, the third edition also includes a substantialamount of new material scattered throughout the book Most is the result of featuresthat have been added to C++ since the previous edition was prepared New or

expanded coverage includes the following topics: the Standard Template Library,run-time type ID (RTTI), the new casting operators, new features of templates,

namespaces, new-style headers, and the modern-style I/O system Also, some

fundamental changes to the way new and delete are implemented are described and

several new keywords are discussed

Frankly, if you have not taken a close look at C++ for the past few years, you will

be surprised at how much it has grown and how many new features have been added.It's not the same old C++ that you learned years ago

■ The Standard Function Library

■ The Standard Class Library

■ Sample C++ applications

Part One provides a comprehensive discussion of the C subset of C++ As mostreaders will know, C is the foundation upon which C++ was built It is the C subset

that defines the bedrock features of C++, including such things as for loops and if

statements It also defines the essential nature of C++'s block structure, pointers, andfunctions Since many readers are already familiar with and proficient in C, discussingthe C subset separately in Part One prevents the knowledgeable C programmer fromhaving to "wade through" reams of information he or she already knows Instead, the

experienced C programmer can simply turn to the sections of this book that cover the

C++-specific features

Part Two discusses in detail the extensions and enhancements to C added by C++

These include its object-oriented features such as classes, constructors, destructors, and

templates Thus, Part Two covers those constructs that "make C++, C++."

Part Three describes the standard function library and Part Four examines the

standard class library, including the STL (Standard Template Library) Part Five shows

two practical examples of applying C++ and object-oriented programming

A Book for All Programmers

This C++ reference is designed for all C++ programmers, regardless of their experience

level It does assume, however, a reader able to create at least a simple program If you

are just learning C++, this book will make an excellent companion to any C++ tutorial

and serve as a source of answers to your specific questions Experienced C++ pros will

find the coverage of the many new features added by the International Standard

especially useful

If You're Using Windows

If your computer uses Windows, then you have chosen the right language C++ is

completely at home with Windows programming However, none of the programs

in this book are Windows programs Instead, they are console-based programs The

reason for this is easy to understand: Windows programs are, by their nature, large and

complex The overhead required to create even a minimal Windows skeletal program

is 50 to 70 lines of code To write Windows programs that demonstrate the features of

C++ would require hundreds of lines of code each Put simply, Windows is not an

appropriate environment in which to discuss the features of a programming language

However, you can still use a Windows-based compiler to compile the programs in this

book because the compiler will automatically create a console session in which to

execute your program

Don't Forget: Code On The Web

Remember, the source code for all of the programs in this book is available

free-of-charge on the Web at http://www.osborne.com Downloading this code

prevents you from having to type in the examples

For Further Study

C++: The Complete Reference is your gateway into the "Herb Schildt" series of

programming books Here is a partial list of Schildt's other books

If you want to learn more about C++, then you will find these books especiallyhelpful

C++ From the Ground Up

Teach Yourself C++

Expert C++

If you want to learn more about C, the foundation of C++, we recommend

Teach Yourself C

C: The Complete Reference

The Annotated ANSI C Standard

If you will be developing programs for the Web, you will want to read

Java: The Complete Reference

co-authored by Herbert Schildt and Patrick Naughton

Finally, if you want to program for Windows, we recommend

Windows 98 Programming From the Ground Up

Windows NT 4 From the Ground Up

MFC Programming From the Ground Up

When you need solid answers, fast, turn to Herbert Schildt,

the recognized authority on programming.

Part I

The Foundation of C++:

The C Subset

T his book divides the description of the C++ language into

two parts Part One discusses the C-like features of C++.

This is commonly referred to as the C subset of C++ Part Two

describes those features specific to C++ Together, they describe the entire C++ language.

As you may know, C++ was built upon the foundation of C.

In fact, C++ includes the entire C language, and (with minor exceptions) all C programs are also C++ programs When C++ was invented, the C language was used as the starting point To C were added several new features and extensions designed to

1

support object-oriented programming (OOP) However, the C-like aspects of

C++ were never abandoned, and the ANSI/ISO C standard is a base document for

the International Standard for C++ Thus, an understanding of C++ implies an

understanding of C

In a book such as this Complete Reference, dividing the C++ language into two

pieces—the C foundation and the C++-specific features—achieves three major benefits:

1 The dividing line between C and C++ is clearly delineated

2 Readers already familiar with C can easily find the C++-specific information

3 It provides a convenient place in which to discuss those features of C++ thatrelate mostly to the C subset

Understanding the dividing line between C and C++ is important because both arewidely used languages and it is very likely that you will be called upon to write ormaintain both C and C++ code When working on C code, you need to know where Cends and C++ begins Many C++ programmers will, from time to time, be required towrite code that is limited to the "C subset." This will be especially true for embeddedsystems programming and the maintenance of existing applications Knowing thedifference between C and C++ is simply part of being a top-notch professional C++programmer

A clear understanding of C is also valuable when converting C code into C++ To

do this in a professional manner, a solid knowledge of C is required For example,without a thorough understanding of the C I/O system, it is not possible to efficientlyconvert an I/O-intensive C program into C++

Many readers already know C Covering the C-like features of C++ in their ownsection makes it easier for the experienced C programmer to quickly and easily findinformation about C++ without having to wade through reams of information that he

or she already knows Of course, throughout Part One, any minor differences between

C and C++ are noted Also, separating the C foundation from the more advanced,object-oriented features of C++ makes it possible to tightly focus on those advancedfeatures because all of the basics will have already been discussed

Although C++ contains the entire C language, not all of the features provided bythe C language are commonly used when writing "C++-style" programs For example,the C I/O system is still available to the C++ programmer even though C++ defines itsown, object-oriented version The preprocessor is another example The preprocessor isvery important to C, but less so to C++ Discussing several of the "C-only" features inPart One prevents them from cluttering up the remainder of the book

The C subset described in Part One constitutes the core of C++ and the foundation upon which C++'s object-oriented features are built All the features described here are part of C++ and available for your use.

Part One of this book is adapted from my book C: The Complete Reference (Osborne/McGraw-Hill) If you are particularly interested in C, you will find this book helpful.

Note

Remember

Chapter 1

An Overview of C

3

C++

To understand C++ is to understand the forces that drove its creation, the ideas

that shaped it, and the legacy it inherits Thus, the story of C++ begins with C.This chapter presents an overview of the C programming language, its origins, itsuses, and its underlying philosophy Since C++ is built upon C, this chapter provides

an important historical perspective on the roots of C++ Much of what makes C++what it is had its genesis in the C language

The Origins of C

C was invented and first implemented by Dennis Ritchie on a DEC PDP-11 that usedthe Unix operating system C is the result of a development process that started with anolder language called BCPL BCPL was developed by Martin Richards, and it

influenced a language called B, which was invented by Ken Thompson B led to thedevelopment of C in the 1970s

For many years, the de facto standard for C was the version supplied with the Unix

version 5 operating system It was first described in The C Programming Language by

Brian Kernighan and Dennis Ritchie (Englewood Cliffs, N.J.: Prentice-Hall, 1978) In thesummer of 1983 a committee was established to create an ANSI (American NationalStandards Institute) standard that would define the C language once and for all Thestandardization process took six years (much longer than anyone reasonably expected).The ANSI C standard was finally adopted in December 1989, with the first copiesbecoming available in early 1990 The standard was also adopted by ISO (InternationalStandards Organization) and is now referred to as the ANSI/ISO C standard For

simplicity, this book will use the term Standard C when referring to the ANSI/ISO C

standard Today, all mainstream C/C++ compilers comply with Standard C Standard

C is the foundation upon which C++ is built

C Is a Middle-Level Language

C is often called a middle-level computer language This does not mean that C is less

powerful, harder to use, or less developed than a high-level language such as BASIC

or Pascal, nor does it imply that C has the cumbersome nature of assembly language(and its associated troubles) Rather, C is thought of as a middle-level language because

it combines the best elements of high-level languages with the control and flexibilityofassembly language Table 1-1 shows how C fits into the spectrum of computer

languages

As a middle-level language, C allows the manipulation of bits, bytes, and

addresses—the basic elements with which the computer functions Despite this fact

C code is also very portable Portability means that it is easy to adapt software written

for one type of computer or operating system to another For example, if you can easilyconvert a program written for DOS so that it runs under Windows, that program isportable

All high-level programming languages support the concept of data types A data

type defines a set of values that a variable can store along with a set of operations that

can be performed on that variable Common data types are integer, character, and real.Although C has five basic built-in data types, it is not a strongly typed language, as arePascal and Ada C permits almost all type conversions For example, you may freely

intermix character and integer types in an expression

Unlike a high-level language, C performs almost no run-time error checking For

example, no check is performed to ensure that array boundaries are not overrun Thesetypes of checks are the responsibility of the programmer

In the same vein, C does not demand strict type compatibility between a parameterand an argument As you may know from your other programming experience, a

high-level computer language will typically require that the type of an argument be

(more or less) exactly the same type as the parameter that will receive the argument

However, such is not the case for C Instead, C allows an argument to be of any type

as long as it can be reasonably converted into the type of the parameter Further, C

provides all of the automatic conversions to accomplish this

Modula-2PascalCOBOLFORTRANBASIC

C++

CFORTH

Assembler

Table 1-1 C's Place in the World of Programming Languages

C is special in that it allows the direct manipulation of bits, bytes, words, andpointers This makes it well suited for system-level programming, where these

operations are common

Another important aspect of C is that it has only 32 keywords (27 from the

Kernighan and Ritchie de facto standard, and five added by the ANSI standardizationcommittee), which are the commands that make up the C language High-level

languages typically have several times more keywords As a comparison, considerthat most versions of BASIC have well over 100 keywords!

C Is a Structured Language

In your previous programming experience, you may have heard the term

block-structured applied to a computer language Although the term block-block-structured

language does not strictly apply to C, C is commonly referred to simply as a

structured language It has many similarities to other structured languages, such

as ALGOL, Pascal, and Modula-2

The reason that C (and C++) is not, technically, a block-structured language is that block-structured languages permit procedures or functions to be declared inside other procedures or functions Since C does not allow the creation of functions within functions, it cannot formally be called block-structured.

The distinguishing feature of a structured language is compartmentalization of code

and data This is the ability of a language to section off and hide from the rest of theprogram all information and instructions necessary to perform a specific task Oneway that you achieve compartmentalization is by using subroutines that employ local(temporary) variables By using local variables, you can write subroutines so that theevents that occur within them cause no side effects in other parts of the program Thiscapability makes it very easy for programs to share sections of code If you developcompartmentalized functions, you only need to know what a function does, not how itdoes it Remember, excessive use of global variables (variables known throughout theentire program) may allow bugs to creep into a program by allowing unwanted sideeffects (Anyone who has programmed in standard BASIC is well aware of this

problem.)

The concept of compartmentalization is greatly expanded by C++ Specifically, in C++, one part of your program may tightly control which other parts of your program are allowed access.

A structured language allows you a variety of programming possibilities It

directly supports several loop constructs, such as while, do-while, and for In a structured language, the use of goto is either prohibited or discouraged and is not the

common form of program control (as is the case in standard BASIC and traditional

Note

Note

FORTRAN, for example) A structured language allows you to place statements

anywhere on a line and does not require a strict field concept (as some older

language is that it is nonstructured Today, few programmers would consider using

a nonstructured language for serious, new programs

New versions of many older languages have attempted to add structured elements.

BASIC is an example However, the shortcomings of these languages can never be

fully mitigated because they were not designed with structured features from the

beginning.

C's main structural component is the function—C's stand-alone subroutine In

C, functions are the building blocks in which all program activity occurs They let

you define and code separately the separate tasks in a program, thus allowing your

programs to be modular After you have created a function, you can rely on it to

work properly in various situations without creating side effects in other parts of

the program Being able to create stand-alone functions is extremely critical in larger

projects where one programmer's code must not accidentally affect another's

Another way to structure and compartmentalize code in C is through the use of

code blocks A code block is a logically connected group of program statements that is

treated as a unit In C, you create a code block by placing a sequence of statements

between opening and closing curly braces In this example,