Head First C

Table of Contents (the real thing)......Page 11
Intro......Page 29
Who is this book for?......Page 30
We know what your brain is thinking......Page 31
Metacognition: thinking about thinking......Page 33
Here’s what WE did:......Page 34
Here’s what YOU can do to bend your brain into submission......Page 35
Read me......Page 36
The technical review team......Page 38
Acknowledgments......Page 39
Safari® Books Online......Page 40
Chapter 1: Getting Started with C: Diving in......Page 41
C is a language for small, fast programs......Page 42
But what does a complete C program look like?......Page 45
But how do you run the program?......Page 49
Two types of command......Page 54
Here’s the code so far......Page 55
Card counting? In C?......Page 57
There’s more to booleans than equals…......Page 58
What’s the code like now?......Page 65
Pulling the ol’ switcheroo......Page 66
Sometimes once is not enough…......Page 69
Loops often follow the same structure…......Page 70
You use break to break out…......Page 71
Your C Toolbox......Page 80
Chapter 2: Memory and Pointers: What are you pointing at?......Page 81
C code includes pointers......Page 82
Digging into memory......Page 83
Set sail with pointers......Page 84
Set sail sou’east, Cap’n......Page 85
Try passing a pointer to the variable......Page 87
Using memory pointers......Page 88
How do you pass a string to a function?......Page 93
Array variables are like pointers…......Page 94
What the computer thinks when it runs your code......Page 95
But array variables aren’t quite pointers......Page 99
Why arrays really start at 0......Page 101
Why pointers have types......Page 102
Using pointers for data entry......Page 105
Be careful with scanf()......Page 106
fgets() is an alternative to scanf()......Page 107
Anyone for three-card monte?......Page 109
Oops…there’s a memory problem…......Page 110
String literals can never be updated......Page 112
In memory: char *cards=“JQK”;......Page 113
If you’re going to change a string, make a copy......Page 114
In memory: char cards[]=“JQK”;......Page 115
Memory memorizer......Page 120
Your C Toolbox......Page 121
Chapter 2.5: Strings: String theory......Page 123
Desperately seeking Frank......Page 124
Create an array of arrays......Page 125
Find strings containing the search text......Page 126
Using the strstr() function......Page 129
It’s time for a code review......Page 134
Array of arrays vs. array of pointers......Page 138
Your C Toolbox......Page 141
Chapter 3: Creating Small Tools: Do one thing and do it well......Page 143
Small tools can solve big problems......Page 144
Here’s how the program should work......Page 148
But you’re not using files…......Page 149
You can use redirection......Page 150
You can redirect the Standard Input with <…......Page 151
…and redirect the Standard Output with >......Page 152
But there’s a problem with some of the data…......Page 154
Introducing the Standard Error......Page 160
By default, the Standard Error is sentto the display......Page 161
fprintf() prints to a data stream......Page 162
Let’s update the code to use fprintf()......Page 163
Small tools are flexible......Page 168
Don’t change the geo2json tool......Page 169
A different task needs a different tool......Page 170
Connect your input and output with a pipe......Page 171
The bermuda tool......Page 172
But what if you want to output tomore than one file?......Page 177
Roll your own data streams......Page 178
There’s more to main()......Page 181
Overheard at the Head First Pizzeria......Page 188
Let the library do the work for you......Page 189
Your C Toolbox......Page 196
Chapter 4: Using Multiple Source Files: Break it down, build it up......Page 197
Your quick guide to data types......Page 202
Don’t put something big into something small......Page 203
Use casting to put floats into whole numbers......Page 204
Oh no…it’s the out-of-work actors…......Page 208
Let’s see what’s happened to the code......Page 209
Compilers don’t like surprises......Page 211
Split the declaration from the definition......Page 213
Creating your first header file......Page 214
If you have common features…......Page 222
You can split the code into separate files......Page 223
Compilation behind the scenes......Page 224
The shared code needs its own header file......Page 226
It’s not rocket science…or is it?......Page 229
Don’t recompile every file......Page 230
First, compile the source into object files......Page 231
It’s hard to keep track of the files......Page 236
Automate your builds with the make tool......Page 238
How make works......Page 239
Tell make about your code with a makefile......Page 240
Liftoff!......Page 245
Your C Toolbox......Page 246
C Lab 1: Arduino......Page 247
The spec: make your houseplant talk......Page 248
Build the physical device......Page 250
Here’s what your code should do......Page 252
Here are some useful Arduino functions......Page 254
The finished product......Page 255
Chapter 5: Structs, Unions, and Bitfields: Roll your own structures......Page 257
Sometimes you need to hand around a lot of data......Page 258
Cubicle conversation......Page 259
Create your own structured data types with a struct......Page 260
Just give them the fish......Page 261
Read a struct’s fields with the “.” operator......Page 262
Can you put one struct inside another?......Page 267
How do you update a struct?......Page 276
The code is cloning the turtle......Page 278
You need a pointer to the struct......Page 279
(*t).age vs. *t.age......Page 280
Sometimes the same type of thing needs different types of data......Page 286
A union lets you reuse memory space......Page 287
How do you use a union?......Page 288
An enum variable stores a symbol......Page 295
Sometimes you want control at the bit level......Page 301
Bitfields store a custom number of bits......Page 302
Your C Toolbox......Page 306
Do you need flexible storage?......Page 307
Linked lists are like chains of data......Page 309
Linked lists allow inserts......Page 310
Create a recursive structure......Page 311
Create islands in C…......Page 312
Inserting values into the list......Page 313
Use the heap for dynamic storage......Page 318
Give the memory back when you’re done......Page 319
Ask for memory with malloc()…......Page 320
Oh, no! It’s the out-of-work actors…......Page 321
Let’s fix the code using the strdup() function......Page 326
Free the memory when you’re done......Page 330
Exhibit A: the source code......Page 338
An overview of the SPIES system......Page 340
Software forensics: using valgrind......Page 342
Look at the evidence......Page 343
The fix on trial......Page 347
Your C Toolbox......Page 349
Chapter 7: Advanced Functions: Turn your functions up to 11......Page 351
Looking for Mr. Right…......Page 352
Pass code to a function......Page 356
You need to tell find() the name of a function......Page 357
Every function name is a pointer to the function…......Page 358
…but there’s no function data type......Page 359
How to create function pointers......Page 360
Get it sorted with the C Standard Library......Page 365
Use function pointers to set the order......Page 366
Automating the Dear John letters......Page 374
Create an array of function pointers......Page 378
Make your functions streeeeeetchy......Page 383
Your C Toolbox......Page 390
Chapter 8: Static and Dynamic Libraries: Hot-swappable code......Page 391
Code you can take to the bank......Page 392
Angle brackets are for standard headers......Page 394
But what if you want to share code?......Page 395
Sharing .h header files......Page 396
Share .o object files by using the full pathname......Page 397
An archive contains .o files......Page 398
Create an archive with the ar command…......Page 399
Finally, compile your other programs......Page 400
The Head First Gym is going global......Page 405
Calculating calories......Page 406
But things are a bit more complex…......Page 409
Programs are made out of lots of pieces…......Page 410
Dynamic linking happens at runtime......Page 412
Can you link .a at runtime?......Page 413
First, create an object file......Page 414
What you call your dynamic library depends on your platform......Page 415
Your C Toolbox......Page 427
C Lab 2: OpenCV......Page 429
The spec: turn your computer into an intruder detector......Page 430
What your code should do......Page 432
The finished product......Page 434
Chapter 9: Processes and System Calls: Breaking boundaries......Page 437
System calls are your hotline to the OS......Page 438
Then someone busted into the system…......Page 442
Security’s not the only problem......Page 443
The exec() functions give you more control......Page 444
There are many exec() functions......Page 445
The array functions: execv(), execvp(), execve()......Page 446
Passing environment variables......Page 447
Most system calls go wrong in the same way......Page 448
Read the news with RSS......Page 456
exec() is the end of the line for your program......Page 460
Running a child process with fork() + exec()......Page 461
Your C Toolbox......Page 467
Chapter 10: Interprocess Communication: It\'s good to talk......Page 469
Redirecting input and output......Page 470
A look inside a typical process......Page 471
Redirection just replaces data streams......Page 472
fileno() tells you the descriptor......Page 473
Sometimes you need to wait…......Page 478
Stay in touch with your child......Page 482
Connect your processes with pipes......Page 483
Case study: opening stories in a browser......Page 484
In the parent......Page 485
Opening a web page in a browser......Page 486
The death of a process......Page 491
Catching signals and running your own code......Page 492
sigactions are registered with sigaction()......Page 493
Rewriting the code to use a signal handler......Page 494
Use kill to send signals......Page 497
Sending your code a wake-up call......Page 498
Your C Toolbox......Page 506
Chapter 11: Sockets and Networking: There\'s no place like 127.0.0.1......Page 507
The Internet knock-knock server......Page 508
Knock-knock server overview......Page 509
BLAB: how servers talk to the Internet......Page 510
A socket’s not your typical data stream......Page 512
Sometimes the server doesn’t start properly......Page 516
Why your mom always told you to check for errors......Page 517
Reading from the client......Page 518
The server can only talk to one person at a time......Page 525
You can fork() a process for each client......Page 526
Writing a web client......Page 530
Clients are in charge......Page 531
Create a socket for an IP address......Page 532
getaddrinfo() gets addresses for domains......Page 533
Your C Toolbox......Page 540
Chapter 12: Threads: It\'s a parallel world......Page 541
Tasks are sequential…or not…......Page 542
…and processes are not always the answer......Page 543
Simple processes do one thing at a time......Page 544
Employ extra staff: use threads......Page 545
How do you create threads?......Page 546
Create threads with pthread_create......Page 547
The code is not thread-safe......Page 552
You need to add traffic signals......Page 553
Use a mutex as a traffic signal......Page 554
Your C Toolbox......Page 561
C Lab 3: Blasteroids......Page 563
Write the arcade game Blasteroids......Page 564
Your mission: blast the asteroids without getting hit......Page 565
Allegro......Page 566
What does Allegro do for you?......Page 567
Building the game......Page 568
The spaceship......Page 569
The blast......Page 572
The asteroid......Page 573
Use transformations to move things around......Page 575
The finished product......Page 576
It’s been great having you here in Cville!......Page 577
Appendix i: Leftovers: The top ten things (we didn\'t cover)......Page 579
#1. Operators......Page 580
#2. Preprocessor directives......Page 582
#3. The static keyword......Page 583
#4. How big stuff is......Page 584
#5. Automated testing......Page 585
#6. More on gcc......Page 586
#7. More on make......Page 588
#8. Development tools......Page 590
#9. Creating GUIs......Page 591
#10. Reference material......Page 592
Appendix ii: C Topics: Revision roundup......Page 593
Basics......Page 594
Pointers and memory......Page 596
Strings......Page 597
Data streams......Page 598
Data types......Page 600
Multiple files......Page 601
Structs......Page 602
Unions and bitfields......Page 603
Data structures......Page 604
Dynamic memory......Page 605
Advanced functions......Page 606
Static and dynamic libraries......Page 608
Processes and communication......Page 610
Sockets and networking......Page 612
Threads......Page 613
Index......Page 615