Table Of Content00 067231861x FM 12/11/02 10:01 AM Page i
Teach Yourself
C
24
in
Hours
Tony Zhang
SECOND EDITION
201 West 103rd St., Indianapolis, Indiana, 46290 USA
00 067231861x FM 12/11/02 10:01 AM Page ii
Sams Teach Yourself C in 24 Hours, ASSOCIATEPUBLISHER
Michael Stephens
Second Edition
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Copyright ©2000 by Sams Publishing Carol Ackerman
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Contents at a Glance
Introduction 1
Part I The Basics of C 9
Hour 1 Taking the First Step 11
2 Writing Your First C Program 27
3 Learning the Structure of a C Program 41
4 Understanding Data Types and Keywords 55
5 Handling Standard Input and Output 71
Part II Operators and Control-flow Statements 89
Hour 6 Manipulating Data 91
7 Working with Loops 105
8 Using Conditional Operators 121
9 Working with Data Modifiers and Math Functions 141
10 Controlling Program Flow 155
Part III Pointers and Arrays 173
Hour 11 Understanding Pointers 175
12 Understanding Arrays 189
13 Manipulating Strings 207
14 Understanding Scope and Storage Classes 223
Part IV Functions and Dynamic Memory Allocation 241
Hour 15 Working with Functions 243
16 Applying Pointers 259
17 Allocating Memory 279
18 Using Special Data Types and Functions 295
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Part V Structure, Union, File I/O, and More 311
Hour 19 Understanding Structures 313
20 Understanding Unions 333
21 Reading and Writing with Files 355
22 Using Special File Functions 373
23 Compiling Programs:The C Preprocessor 391
24 Where Do You Go from Here? 409
Part VI Appendixes 437
Appendix A ANSI Standard Header Files 439
B Answers to Quiz Questions and Exercises 441
Index 503
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Table of Contents
Introduction 1
Who Should Read This Book?................................................................................1
Special Features of This Book................................................................................1
Programming Examples..........................................................................................2
Q&A and Workshop................................................................................................4
Conventions Used in This Book..............................................................................4
What You’ll Learn in 24 Hours................................................................................4
Part I The Basics of C 9
Hour 1 Taking the First Step 11
What Is C? ............................................................................................................12
The ANSI C Standard ..........................................................................................15
Assumptions About You........................................................................................16
Setting Up Your System........................................................................................16
Hardware..........................................................................................................16
Software............................................................................................................16
A Sample C Programming Setup ....................................................................17
Using Microsoft’s Compiler ............................................................................18
Using Borland’s Compiler................................................................................21
Summary................................................................................................................24
Q&A......................................................................................................................25
Workshop ..............................................................................................................25
Quiz..................................................................................................................25
Hour 2 Writing Your First C Program 27
A Simple C Program..............................................................................................28
Comments..............................................................................................................29
The #includeDirective ........................................................................................31
Header Files......................................................................................................32
Angle Brackets (< >) and Double Quotes (“ “)..............................................32
The main()Function..............................................................................................33
The Newline Character (\n) ............................................................................33
The returnStatement......................................................................................34
The exit()Function........................................................................................34
Compiling and Linking..........................................................................................34
What’s Wrong with My Program?........................................................................36
Debugging Your Program......................................................................................37
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vi Sams Teach Yourself C in 24 Hours
Summary................................................................................................................37
Q&A......................................................................................................................38
Workshop ..............................................................................................................38
Quiz..................................................................................................................38
Exercises ..........................................................................................................39
Hour 3 Learning the Structure of a C Program 41
The Basics of a C Program....................................................................................42
Constants and Variables....................................................................................42
Expressions ......................................................................................................42
Statements........................................................................................................45
Statement Blocks..............................................................................................45
Anatomy of a C Function......................................................................................46
Determining a Function’s Type........................................................................46
Giving a Function a Valid Name......................................................................47
Passing Arguments to C Functions..................................................................47
The Beginning and End of a Function ............................................................48
The Function Body ..........................................................................................48
Making Function Calls..........................................................................................49
Summary................................................................................................................51
Q&A......................................................................................................................52
Workshop ..............................................................................................................52
Quiz..................................................................................................................52
Exercises ..........................................................................................................53
Hour 4 Understanding Data Types and Keywords 55
C Keywords ..........................................................................................................56
The charData Type ..............................................................................................57
Character Variables ..........................................................................................58
Character Constants..........................................................................................58
The Escape Character (\)..................................................................................59
Printing Characters ..........................................................................................60
The intData Type ................................................................................................62
Declaring Integer Variables..............................................................................62
Showing the Numeric Values of Characters....................................................63
The floatData Type ............................................................................................64
Declaring Floating-Point Variables..................................................................64
The Floating-Point Format Specifier (%f)........................................................65
The doubleData Type ..........................................................................................67
Using Scientific Notation......................................................................................67
Naming a Variable..................................................................................................68
Summary................................................................................................................68
Q&A......................................................................................................................68
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Contents vii
Workshop ..............................................................................................................69
Quiz..................................................................................................................69
Exercises ..........................................................................................................70
Hour 5 Handling Standard Input and Output 71
Understanding Standard I/O ................................................................................72
Getting Input from the User..................................................................................72
Using the getc()Function ..............................................................................72
Using the getchar()Function ........................................................................74
Printing Output on the Screen ..............................................................................75
Using the putc()Function ..............................................................................75
Another Function for Writing:putchar() ......................................................77
Revisiting the printf()Function..........................................................................78
Converting to Hex Numbers............................................................................79
Specifying the Minimum Field Width..............................................................81
Aligning Output................................................................................................83
Using the Precision Specifier ..........................................................................84
Summary................................................................................................................85
Q&A......................................................................................................................86
Workshop ..............................................................................................................86
Quiz..................................................................................................................87
Exercises ..........................................................................................................87
Part II Operators and Control-flow Statements 89
Hour 6 Manipulating Data 91
Arithmetic Assignment Operators ........................................................................92
The Assignment Operator (=) ..........................................................................92
Combining Arithmetic Operators with =..........................................................92
Getting Negations of Numeric Values ..................................................................95
Incrementing or Decrementing by One ................................................................96
Greater Than or Less Than?..................................................................................98
Using the Cast Operator......................................................................................101
Summary..............................................................................................................102
Q&A....................................................................................................................102
Workshop ............................................................................................................103
Quiz................................................................................................................103
Exercises ........................................................................................................103
Hour 7 Working with Loops 105
The whileLoop ..................................................................................................106
The do-whileLoop..............................................................................................107
Looping Under the forStatement ......................................................................109
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viii Sams Teach Yourself C in 24 Hours
The Null Statement..............................................................................................112
Using Complex Expressions in a forStatement............................................113
Using Nested Loops............................................................................................116
Summary..............................................................................................................118
Q&A....................................................................................................................118
Workshop ............................................................................................................119
Quiz................................................................................................................119
Exercises ........................................................................................................120
Hour 8 Using Conditional Operators 121
Measuring Data Sizes..........................................................................................122
Everything Is Logical..........................................................................................124
The Logical AND Operator (&&)....................................................................124
The Logical OR Operator (||) ......................................................................126
The Logical NEGATION Operator (!)..........................................................128
Manipulating Bits................................................................................................129
Converting Decimal to Hex or Binary ..........................................................129
Using Bitwise Operators................................................................................130
Using Shift Operators ....................................................................................133
What Does x?y:zMean? ....................................................................................135
Summary..............................................................................................................137
Q&A....................................................................................................................137
Workshop ............................................................................................................138
Quiz................................................................................................................138
Exercises ........................................................................................................138
Hour 9 Working with Data Modifiers and Math Functions 141
Enabling or Disabling the Sign Bit......................................................................142
The signedModifier......................................................................................142
The unsignedModifier..................................................................................143
Changing Data Sizes............................................................................................145
The shortModifier........................................................................................145
The longModifier..........................................................................................145
Adding h,l,or Lto printfand fprintfFormat Specifiers..........................147
Mathematical Functions in C..............................................................................148
Calling sin(),cos(),and tan()....................................................................149
Calling pow()and sqrt()..............................................................................150
Summary..............................................................................................................152
Q&A....................................................................................................................153
Workshop ............................................................................................................154
Quiz................................................................................................................154
Exercises ........................................................................................................154
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Contents ix
Hour 10 Controlling Program Flow 155
Always Saying “if…” ..........................................................................................156
The if-elseStatement..................................................................................158
Nested ifStatements......................................................................................160
The switchStatement..........................................................................................161
The breakStatement............................................................................................164
Breaking an Infinite Loop....................................................................................166
The continueStatement......................................................................................167
The gotoStatement..............................................................................................168
Summary..............................................................................................................170
Q&A....................................................................................................................170
Workshop ............................................................................................................171
Quiz................................................................................................................171
Exercises ........................................................................................................172
Part III Pointers and Arrays 173
Hour 11 Understanding Pointers 175
What Is a Pointer?................................................................................................176
Address (Left Value) Versus Content (Right Value)............................................176
The Address-of Operator (&)..........................................................................177
Declaring Pointers................................................................................................179
The Dereference Operator (*)........................................................................182
Null Pointers ..................................................................................................183
Updating Variables via Pointers..........................................................................183
Pointing to the Same Memory Location..............................................................184
Summary..............................................................................................................186
Q&A....................................................................................................................187
Workshop ............................................................................................................188
Quiz................................................................................................................188
Exercises ........................................................................................................188
Hour 12 Understanding Arrays 189
What Is an Array?................................................................................................190
Declaring Arrays............................................................................................190
Indexing Arrays..............................................................................................190
Initializing Arrays ..........................................................................................191
The Size of an Array............................................................................................192
Arrays and Pointers..............................................................................................194
Displaying Arrays of Characters....................................................................196
The Null Character (‘\0’)..............................................................................198
Multidimensional Arrays ....................................................................................199
