Let us C/ Yashavant Kanetkar

Contents
I. Getting Started •
What is C 2
Getting Started with C ' 4
The C Character Set 5
Constants, Variables and Keywords 5
Types of C Constants y
Rules for Constructing integer Constants 7
Rules for Constructing Real Constants 8
Rules for Constructing Character Constants 9
Types of C Variables 10
Rules for Constructing Variable Names 10
C Keywords 11
The First C Program 12
Compilation and Execution Ig
Receiving Input 19
C Instructions 91
Type Declaration Instruction 22
Arithmetic Instruction 23
Integer and Float Conversions 27
Type Conversion in Assignments 28
Hierarchy of Operations 30
Associativity of Operators 33
Control Instructions in C 35
'
Summary 3^
Exercise 3^
2. The Decision Control Structure 47
Decisions! Decisions! 48
The // Statement • 49
The Real Thing 53
Multiple Statements within if 55
The if-else Statement 55
Nested f-else's 59

Forms of if
Use of Logical Operators
The else //'Clause
The ! Operator
Hierarchy of Operators Revisited
A Word of Caution
The Conditional Operators
Summary
Exercise
The Loop Control Structure
Loops
The while Loop
Tips and Traps
More Operators
The /or Loop
Nesting of Loops
Multiple Initialisations in the/or Loop
The break Statement
The continue Statement
The do-while Loop
The Odd Loop
Summary
Exercise
The Case Control Structure
Decisions Using switch
The Tips and Traps
switch Versus if-else Ladder
The goto Keyword
Summary
Exercise
Functions & Pointers
What is a Function
Why Use Functions

Passing Values between Functions 167
Scope Rule of Functions 172
Calling Convention I73
One Dicey Issue I74
Advanced Features of Functions 175
Return Type of Function I77
Call by Value and Call by Reference 178
An Introduction to Pointers 178
PointerNotation I79
Back to Function Calls
186
Conclusions 189
Recursion 190
Recursion and Stack I95
Adding Functions to the Library 198
Summary 201
Exercise 202
6. Data Types kevisited 217
Integers, long and short 218
Integers, signed and unsigned 220
Chars, signed and unsigned 221
Floats and Doubles 223
A Few More Issues... 226
Storage Classes in C 227
Automatic Storage Class 228
Register Storage Class 231
Static Storage Class 232
External Storage Class 235
A Few Subtle Issues 238
Which to Use When 240
Summary 241
Exercise 241
7. The C Preprocessor 249
Features
of C Preprocessor 250
Macro Expansion 251
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Macros with Arguments 255
Macros versus Functions 260
File Inclusion 261
Conditional Compilation ' 263
Directives ^ 267
Miscellaneous Directives 268
(3fe/Directive 268
^pragma Directive 269
The Build Process 272
Preprocessing 274
Compilation 274
Assembling 274
Linking 276
Loading 277
Summary 279
Exercise 279
8. Arrays
What are Arrays 286
A Simple Program Using Array 288
More on Arrays 291
Array Initialization 291
Bounds Checking 292
Passing Array Elements to a Function 293
Pointers and Arrays 295
Passing an Entire Array to a Function 303
The Real Thing 304
Two Dimensional Arrays 306
Initializing a 2-Dimensional Array 307
Memory Map ofa 2-Dimensional Array , 308
Pointers and 2-Dimensional Arrays 309
Pointer to an Array 312
Passing 2-D array to a Function 314
Array of Pointers 317
Three Dimensional Array 319
Summary 321
Xlll
Exercise 322
9. Strings 345
What are Strings 346
More about Strings 347
Pointers and Strings 352
Standard Library String Functions 353
strlen() 354
strcpy( ) 356
strcat() 360
strcmp() 361
Two-Dimensional Array of Characters 362
Array of Pointers to Strings 365
Limitation of Array of Pointers to Strings 369
Solution 370
Summary 371
Exercise 372
10. Structures
Why Use Structures 382
Declaring a Structure 385
Accessing Structure Elements 388
How Structure Elements are Stored 388
Array of Structures 390
Additional Features of Structures 392
Uses of Structures 402
Summary 403
Exercise 404
11. Console Input/Output 413
Types ofI/O' 414
Console I/O Functions 415
Formatted Console I/O Functions 416
sprintf() and sscanf() Functions 425
Unformatted Console I/O Functions 426
Summary 430
xiv
Exercise
12. File Input/Output
Data Organization
File Operations
Opening a File
Reading from a File ^
Trouble in Opening a File
Closing the File
Counting Characters, Tabs, Spaces,...
A File-copy Program
Writing to a File
File Opening Modes
String (line) I/O in Files
The Awkward Newline
Record I/O in Files
Text Files and Binary Files
Record I/O Revisited
Database Management
Low Level Disk I/O
A Low Level File-copy Program
I/O Under Windows
Summary
Exercise
13. More Issues In Input/Output
Using argc and argv
Detecting Errors in Reading/Writing
Standard I/O Devices
I/O Redirection
Redirecting the Output
Redirecting the Input
Both Ways at Once

14. Operations On Bits 505
Bitwise Operators 506
One's Complement Operator 508
Right Shift Operator 510
Left Shift Operator 512
Bitwise AND Operator 517
Bitwise OR Operator 522
Bitwise XOR Operator 523
The showbits() Function 525
Hexadecimal Numbering System 526
Relationship between Binary and Hex 527
Summary 529
Exercise 530
15. Miscellaneous Features 535
Enumerated Data Type 536
Uses ofEnumerated Data Type 537
Are Enums Necessary • 540
Renaming Data Types with typedef 541
Typecasting 543
Bit Fields 545
Pointers to Functions 547
Functions Returning Pointers 550
Functions with Variable Number ofArguments 551
Unions . 555
Union of Structures 561
Utility of Unions 563
The volatile Qualifier ^ 565
Summary 565
Exercise - 566
16. C Under Windows 571
Salient Features of Windows Programming 572
Powerful API Function 572
Hardware Independent Programming 573
Event Driven Programming Model 574
17.
The First Windows Program
Graphics Under Windows
Device Independent Drawing
Hello Windows
Drawing Shapes
Types of Pens
Types of Brushes
Freehand Drawing, the Paintbrush Style
Capturing the Mouse
Device Context, a Closer Look
Displaying a Bitmap
Animation at Work
WM_CREATE and OnCreate()
616
WM_TIMER and OnTimer()
616
A Few More Points...
Windows, the Endless World...
619
Summary
619
Exercise
621
Network & Internet Programming 623
Network Communication
624
Packets and Sockets
626
Before We Start...
627
Protocols
627
IP Addresses
628
Port Numbers
629
Byte Ordering
630
Getting Started...
631
What's The Time Now
634
Creation of Socket
638
Sending Data to a Time Server 639
Receiving Date and Time
640
Communicating with Whois Server
641
Give Me the Home Page 645
Sending and Receiving Emails
647
Two-Way Communication 659

Summary
666
Exercise
18. C Under Linux
669
What is Linux
670
C Programming Under Linux
671
The 'Hello Linux' Program
672
Processes 674
Parent and Child Processes
675
More Processes
679
Zombies and Orphans 681
One Interesting Fact
684
Summary
684
Exercise
685
19. More Linux Programming
687
Communication using Signals
688
Handling Multiple Signals
691
Registering a Common Handler
693
Blocking Signals
695
Event Driven Programming
698
Where Do You Go From Here
703