Become an xcoder

BECOME AN XCODER

Copyright © 2006 by Bert Altenburg, Alex Clarke and Philippe Mougin. Version 1.2.

Attribution: The licensors, Bert Altenburg, Alex Clarke and Philippe Mougin, permit others to copy,
modify and distribute the work. In return, the licensees must give the original authors credit.

Non-commercial: The licensors permit others to copy, modify and distribute the work and use the
work in paid-for and free courses. In return, licensees may not sell the work itself, although it may
accompany other work that is sold.

2

BECOME AN XCODER

__________________________________________________ 4

0 ______________________________________ 5

1 _____________________________ 7

2 __________________________ 13

3 ______________________________________________ 14

4 _______________________________________ 20

5 _____________________________________ 25

6 __________________________________________ 33

7 while _______________________________ 36

8 GUI ___________________ 39

9 _______________________________________ 55

10 awakeFromNib_____________________________________ 59

11 ______________________________________________ 61

12 ______________________________________________ 63

13 ______________________________________________ 69

14 _________________________________________ 73

15 __________________________________________ 75

3

BECOME AN XCODER

Apple Cocoa
Xcode Mac OS X Apple

Mac
Objective-C Xcode
(GUI)

[4]

[4.3] [4]

volume = baseArea * height; // [4.3]

Xcode

4

BECOME AN XCODER 0

0

Mac Macintosh

1. Mac Mac Mac
Mac Objective-C AppleScript
AppleScript
AppleScript for Absolute Starters

http://www.macscripter.net/books

2. Macintosh PC
Mac T Mac
Mac Mac

distributed computing, DC
Folding@home SETI@home
DC DC
Mac DC
Mac
DC Mac
Mac
Mac DC
DC

http://distributedcomputing.info/projects.html

3. Macintosh

4. Macintosh

5

BECOME AN XCODER 0

5. Macintosh

DC

6

BECOME AN XCODER 1

1

Xcode

Objective-C

2+6=

=3*4 *

x y

2+6=x

y=3*4

Objective-C
Objective-C statement

[1]
x = 4;

x 4
... [1]
compiler
Mac 0 1

Mac

7

BECOME AN XCODER 1

bug
debugging

x
pictureWidth [2]

[2]
pictureWidth = 8;

pictureWidth pictureWIDTH PictureWidth

[2]

Objective-C Objective-C
pictureWidth

"_"

door8k do8or do_or
door 8 8door
Door8

[3]

[3]
pictureWidth=8;
pictureHeight=6;
pictureSurfaceArea=pictureWidth*pictureHeight;

8

BECOME AN XCODER 1

[4]
pictureWidth = 8;
pictureHeight = 6;
pictureSurfaceArea = pictureWidth * pictureHeight;

[5]

[5]
pictureWidth = 8;
pictureHeight = 4.5;

integers [5.1] [5.2]

floating-
point

[5]

" "

[6]
int pictureWidth;
float pictureHeight, pictureSurfaceArea;
pictureWidth = 8;

[6.1] int pictureWidth integer
[6.2]
float
pictureWidth int
float pictureSur-
faceArea [6.2]

int float

int float
long long double

9

BECOME AN XCODER 1

[7]
unsigned int chocolateBarsInStock;

unsigned int unsigned int

[8]

[8]
int x = 10;
float y= 3.5, z = 42;

operators

+

-

/

*

Objective-C

x = x + 1; [9] [10]

[9]
x++;

[10]
++x;

x ++
[11] [12]

[11]
x = 10;

10

BECOME AN XCODER 1

y = 2 * (x++);

[12]
x = 10;
y = 2 * (++x);

[11] y 20 x 11 [12.2]
x 2 1 x 11 y 22 [12]
[13]

[13]
x = 10;
x++;
y = 2 * x;

* / + - 2*3+4 10
2 * (3 + 4) 14

[14, 15]

[14]
int x = 5, y = 12, ratio;
ratio = y / x;

[15]
float x = 5, y = 12, ratio;
ratio = y / x;

[14] 2 [15]
2.4

% % operand
%

[16]
int x = 13, y = 5, remainder;
remainder = x % y;

11

BECOME AN XCODER 1

remainder 3 x 2*y + 3

21 % 7 0 30 % 2 0 50 % 9 5

22 % 7 1 31 % 2 1 60 % 29 2

23 % 7 2 32 % 2 0

24 % 7 3 33 % 2 1

27 % 7 6 34 % 2 0

12

BECOME AN XCODER 2

2

[1]

[1]
float pictureWidth, pictureHeight, pictureSurfaceArea;
pictureWidth = 8.0;

//

Xcode /* */

/*
*/

Xcode
outcomment /* */

13

BECOME AN XCODER 3

3

Objective-C

function

main() main()

main() [1]

[1]
main()
{
// main()
}

[1.1] "main" "main"
main()

[1.2,1.5]

[2]

[2]
main()
{
//

//

14

BECOME AN XCODER 3

pictureWidth = 8.0;

//
}

main()
main()
circleArea() [3]

[3]
main()
{
pictureWidth = 8.0;
}

circleArea() // [3.9]
{

}

[3.9]
main()

circleArea() main() [4]

[4]
main()
{
float pictureWidth, pictureHeight, pictureSurfaceArea,
circleRadius, circleSurfaceArea; // [4.4]
pictureWidth = 8.0;
circleRadius = 5.0; // [4.7]

15

BECOME AN XCODER 3

//
circleSurfaceArea = circleArea(circleRadius); // [4.11]
}

[3]

float [4.4] initialize circleRadius
[4.7] [4.11] circleArea()
circleRadius circleArea() argument
circleRadius circleArea() circleArea()
return [3] circleArea()
[5]

circleArea()

[5]
circleArea(float theRadius) // [5.1]
{
float theArea;
// pi r
theArea = 3.1416 * theRadius * theRadius; //[5.5]
return theArea;
}

[5.1] circleArea()
theRadius theArea [5.5]
[5.3] main [4.4]
theRadius [5.1] [5.6]
[4.11] circleSurfaceArea

[5]

float [6.1]

[6]
float circleArea(float theRadius)
{
float theArea;
theArea = 3.1416 * theRadius * theRadius;
return theArea;
}

16

BECOME AN XCODER 3

[6.1] theArea
float main() circleSurfaceArea
[4.11]

[7]
int throwDice()
{
int noOfEyes;

// 1 6

return noOfEyes;
}

“void”
“return” return

[8]
void beepXTimes(int x);
{
// x
return;
}

pictureSurfaceArea()

[9]
float pictureSurfaceArea(float theWidth, float theHeight)
{
//
}

main() return
0 [10.10] main()
main() "int" [10.1]

[10]

17

BECOME AN XCODER 3

int main()
{
circleRadius, circleSurfaceArea;
pictureWidth = 8;
circleRadius = 5.0;
circleSurfaceArea = circleArea(circleRadius);
return 0; // [10.10]
}

float circleArea(float theRadius) // [10.13]
{
float theArea;
return theArea;
}

[10] [10.1] main() [10.13]
[10.9]
circleArea() main()

warning int main() function
declaration [11.1] [10.13]

[11]
float circleArea(float theRadius); //

int main()
{

[10]

rectangleArea() [12] main()

18

BECOME AN XCODER 3

main()

[12]
float rectangleArea(float length, float width)
{
return (length * width);
}

[12.3]
[10.15] theArea

[12]

rectangleArea

float

float [12.1]

Objective-C
Xcode
[11]

19

BECOME AN XCODER 4

4

Cocoa
NSLog()
" "

NSLog()
Cocoa

NSLog()

[1]
int main()
{
NSLog(@"Julia is a pretty actress.");
return 0;
}

[1] "Julia is a pretty actress." @" "
string

NSLog()
[1]

2005-12-22 17:39:23.084 test[399] Julia is a pretty actress.

character

main()

[2]
NSLog(@"");
NSLog(@" ");

[2.1] empty string
[2.2] space
1

20

BECOME AN XCODER 4

[3.1] n

[3]
NSLog(@"Julia is a pretty nactress.");

Julia is a pretty
actress.

[3.1] escape NSLog()
"n" " "

NSLog()

[4]
NSLog(@"Julia is a pretty actress.n");

[4.1]

Julia is a pretty actress.n

[5]
int x, integerToDisplay;
x = 1;
integerToDisplay = 5 + x;
NSLog(@"The value of the integer is %d.", integerToDisplay);

%d % d deci-
mal number %d
integerToDisplay [5]

The value of the integer is 6.

%f %d

[6]

21

BECOME AN XCODER 4

float x, floatToDisplay;
x = 12345.09876;
floatToDisplay = x/3.1416;
NSLog(@"The value of the float is %f.", floatToDisplay);

.2 % f

[7]
float x, floatToDisplay;
x = 12345.09876;
floatToDisplay = x/3.1416;
NSLog(@"The value of the float is %.2f.", floatToDisplay);

% f % d

[8]
int x = 123456;
NSLog(@"%2d", x);
NSLog(@"%4d", x);
NSLog(@"%6d", x);
NSLog(@"%8d", x);

[8]

123456
123456
123456
123456

[8.1, 8.2]
[8.4]

[9]
float x = 1234.5678
NSLog(@"Reserve a space of 10, and show 2 significant digits.");
NSLog(@"%10.2d", x);

22

BECOME AN XCODER 4

[10.3]
%d %f int float

[10]
int x = 8;
float pi = 3.1416;
NSLog(@"The integer value is %d, whereas the float value is %f.", x, pi);

[10b]
int x = 8;
float pi = 3.1416;
NSLog(@"The integer value is %f, whereas the float value is %f.", x, pi);

The integer value is 0.000000, whereas the float value is 0.000000.

NSLog()

import NSLog()

#import <Foundation/Foundation.h>

[11]
float circleArea(float theRadius);
float rectangleArea(float width, float height);

int main()
{
pictureWidth = 8.0;
circleRadius = 5.0;
pictureSurfaceArea = rectangleArea(pictureWidth, pictureHeight);

23

BECOME AN XCODER 4

NSLog(@"Area of circle: %10.2f.", circleSurfaceArea);
NSLog(@"Area of picture: %f. ", pictureSurfaceArea);
return 0;
}

float circleArea(float theRadius) //
{
float theArea;
return theArea;
}

float rectangleArea(float width, float height) //
{
return width * height;
}

24

BECOME AN XCODER 5

5

Mac Mac
compiler Mac
Apple Xcode Mac OS X
Xcode
http://developer.apple.com

Xcode Developer Applications

Preferences File New Pro-
ject

Xcode

Objective-C GUI Graphical User
Interface Command Line Utility Foundation Tool

25

BECOME AN XCODER 5

justatry
Finish

Terminal

"Groups & Files"
GUI GUI

Xcode "Groups"

Groups & Files justatry Source
justatry.m [1] main()
main()
justatry.m Apple
main()

26

BECOME AN XCODER 5

Xcode main()

[1]

int main (int argc, const char * argv[]) // [1.3]
{
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; // [1.5]

// insert code here...
NSLog(@"Hello, World!");
[pool release]; //[1.9]
return 0;
}

NSLog() import

main()

27

BECOME AN XCODER 5

NSlog

return 0;

main() [1.3]

NSAutoreleasePool [1.5]

pool release [1.9]

" "
main()
[1]
[1.3 1.5 1.9] Objective-
C

main

"pool"

Apple [1] Build and Go
build compile

Build and Go

Run Log
exited stopped 0 main()
[7.9]

[1]
NSLog " "

28

BECOME AN XCODER 5

[2]

int main (int argc, const char * argv[])
{
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

// insert code here...
NSLog(@"Julia is a pretty actress") //
[pool release]; //[2.9]
return 0;
}

Build [2.9]

Xcode

error: parse error before "release".

parse
import
[2.1] # [2.8]
[2.9]

Apple [1] [3]

[3]

float circleArea(float theRadius); // [3.3]

29

BECOME AN XCODER 5

int main (int argc, const char * argv[]) // [3.5]
{
int pictureWidth;
float pictureHeight, pictureSurfaceArea,
pictureWidth = 8;
circleRadius = 5.0;
NSLog(@"Area of picture: %f. Area of circle: %10.2f.",
pictureSurfaceArea, circleSurfaceArea);
[pool release];
return 0;
}

float circleArea(float theRadius) // [3.22]
{
float theArea;
return theArea;
}

float rectangleArea(float width, float height) // [3.29]
{
return width * height;
}

main() cir-
cleArea() [3.22] rectangleArea() [3.29]
main() [3.5] main() Apple

Area of picture: 36.000000. Area of circle: 78.54.

justatry has exited with status 0.

30

BECOME AN XCODER 5

Xcode
Xcode " " breakpoint

Build and Go popup menu

Build and Debug

31

BECOME AN XCODER 5

Xcode debugger

Continue debugger

Mac OS X

Objective-C
GUI

32

BECOME AN XCODER 6

6

[1.2]

[1]
int age = 42;
if (age > 30) // > " "
{
NSLog(@"age is older than thirty."); //[1.4]
}
NSLog(@"Finished."); //[1.6]

[1.2] if...
true
age > 30 [1.4]
[1.6] if

if...else [2]

[2]
int age = 42;
if (age > 30)
{
NSLog(@"age is older than thirty."); //[2.4]
}
else
{
NSLog(@"age is not older thirty."); //[2.7]
}
NSLog(@"Finished."); //[1.6]

[2.7] [2]

[2.2]

==

>

33

BECOME AN XCODER 6

<

>=

<=

!=

-

if

true false

Objective-C true false 1 0 BOOL
"true" 1 YES "false"
0 NO
[3]
int x = 3;
BOOL y;
y = (x == 4); // y 0

AND & &&
OR | ||

[4]
if ( (age >= 18) && (age < 65) )
{
NSLog(@"Probably has to work for a living.");
}

[5]
if (age >= 18)
{

34

BECOME AN XCODER 6

if (age < 65)
{
NSLog(@"Probably has to work for a living.");
}
}

35

BECOME AN XCODER 7 while

7
while

[1]

[1]

Objective-C

[2]
for
2.7

[2]
int x;
for (x = 1; x <= 10; x++)
{
}
NSLog(@"The value of x is %d", x);

[2] [1.4] 10 x 1
x <= 10 x 1
x x++
x 2 10 10
x 11 x <= 10
[2.6] loop x 11 10

x++
[3]

[3]
float celsius, tempInFahrenheit;
for (tempInFahrenheit = 0; tempInFahrenheit <= 200; tempInFahrenheit =
tempInFahrenheit + 20)

36


{
celsius = (tempInFahrenheit - 32.0) * 5.0 / 9.0;
NSLog(@"%10.2f -> %10.2f", tempInFahrenheit, celsius);
}

0.00 -> -17.78
20.00 -> -6.67
40.00 -> 4.44
60.00 -> 15.56
80.00 -> 26.67
100.00 -> 37.78
120.00 -> 48.89
140.00 -> 60.00
160.00 -> 71.11
180.00 -> 82.22
200.00 -> 93.33

Objective-C

while () { }

do {} while ()

for-loop
false loop

[4]
int counter = 1;
while (counter <= 10)
{
counter = counter + 1;
}
NSLog(@"The value of counter is %d", counter);

counter 11

do {} while ()

[5]

37


int counter = 1;
do
{
counter = counter + 1;
}
while (counter <= 10);

NSLog(@"The value of counter is %d", counter);

counter 11

GUI

38

BECOME AN XCODER 8 (GUI)

8
GUI
Objective-C
GUI Objective-C C
C Objective-C C
"Objective" Objective-C object

Objective-C

Objective-C
Objective-C

Safari Objective-C
Mac Safari
message

39


close

Safari

Safari Apple

a.

b. template Safari

b class
behave

instance 76

40


Mac minimize
Dock

access
close " "
close methods

RAM

button text field

close

41


Mac

message sending expression

Objective-C [1.1] [1.2]

[1]
[receiver message];
[receiver message:argument];

[1.2]

Xcode Application
Cocoa Application GUI
Xcode Groups & Files Resources
MainMenu.nib Double-click

42


Xcode MainMenu.nib

Interface Builder File
Hide Others "Window"
"Window"
"Cocoa-" GUI
" " palettes window
GUI "Window"
"System Font Text" GUI

GUI

43


NSButton
NSTextView Apple

"Window"

properties command-shift-
i "Window" In-
stances command-shift-i
pop-up menu Attributes Textured Window
brushed-steel look

Interface Builder inspector

behavior
inherit Objective-C C

44


NSWindow

"close"

" " superclass

hierarchy of inheritance

Objective-C sig-
nal error

implement
override

Apple
Apple

Apple close
invoke close
close recursive
[2]
//
[super close]; // close

"NSObject"
NSObject subclass NSWindow NSResponder
NSObject NSObject

MainMenu.nib Classes NSObject
Classes Subclass NSObject MainMenu.nib
"MAFoo"

45


MAFoo

MAFoo My Application

NS NS Apple NextStep
Apple Next, Inc. NextStep Mac OS X Steve
Jobs

CocoaDev wiki
http://www.cocoadev.com/index.pl?ChooseYourOwnPrefix

Cocoa NSWindow
NSColor MAFoo

Interface Builder Classes Instantiate MAFoo In-
stances MAFoo

MAFoo

46


MAFoo
MAFoo
reference
MAFoo MAFoo
MAFoo

MAFoo
MAFoo MAFoo MAFoo
MAFoo MAFoo trig-
ger FAFoo

outlet

MainFile.nib Classes MAFoo
command-shift-i inspector inspector
Action Add action MAFoo
"setTo5:"
5 Interface Builder
"reset:" 0
":"

47


MAFoo

inspector Outlet outlet "text-
Field"

outlet MAFoo

MAFoo 5 "Set to 5"

"Reset"

48


a) "Reset" MAFoo

b) "Set to 5" MAFoo

c) MAFoo

MainFile.nib Instances Control
Reset MaFoo
MAFoo

MAFoo

inspector MAFoo
"reset:" Connect

49


inspector

MAFoo reset:

Set to 5 MAFoo

MAFoo MAFoo control
Connect

MainMenu.nib MAFoo Classes
MAFoo Classes
Create Files for MAFoo Interface Builder

50


MAFoo

Xcode Other
Sources
Classes

Xcode

51


4 [11.1]

MAFoo.h header file
[3.5] NSObject
NSObject

[3]
/* MAFoo */

#import <Cocoa/Cocoa.h> // [3.3]

@interface MAFoo : NSObject
{
IBOutlet id textField; // [3.7]
}
- (IBAction)reset:(id)sender;
- (IBAction)setTo5:(id)sender;
@end

[3.7] outlet "id" "IB" Interface Buil-
der

IBAction [3.9 3.10] void
MAFoo

Interface Builder Actions

#import <Foundation/Foundation.h> [3.3]

MAFoo.m

[4]
#import "MAFoo.h"

@implementation MAFoo

- (IBAction)reset:(id)sender // [4.5]
{
}

52


- (IBAction)setTo5:(id)sender
{
}

@end

MAFoo.h
reset: setTo5:

MAFoo
Interface Builder MAFoo
MAFoo [5.7 5.12]

[5]
#import "MAFoo.h"


- (IBAction)reset:(id)sender
{
[textField setIntValue:0]; // [5.7]
}

{
[textField setIntValue:5]; // [5.12]
}

@end

textField outlet
Interface Builder outlet
setIntValue: setIntValue:

Xcode Build
and Go

53


54

BECOME AN XCODER 9

9

Apple setIntValue:

Apple
bug-free

Interface Builder
"NSButton"
''System Font Text" "NSTextField"
NSTextField

Xcode Help->Documentation Cocoa
"NSTextField" API-Search
NSText-
Field

NSTextField Class NSTextField

55

BECOME AN XCODER 9

Xcode Cocoa

NSObject

Method Types

NSTextField
NSControl NSView
HTML Inherits from
NSControl NSControl

NSControl
Inherits from NSView : NSResponder : NSObject

Setting the control s value

– setIntValue:

56

BECOME AN XCODER 9

setIntValue:

setIntValue:

- (void)setIntValue:(int)anInt

Sets the value of the receiver’s cell (or selected cell) to
the integer anInt. If the cell is being edited, it aborts all
editing before setting the value; if the cell doesn’t inherit
from NSActionCell, it marks the cell’s interior as needing to
be redisplayed (NSActionCell performs its own updating of
cells).
NSTextField
signature

Objective-C
void setInt-
Value: textField MAFood
(int) anInt
5 0

textField

" " Accessors
setIntValue:

[1]
- (int) intValue

textfield

[2]
resultReceived = [textField intValue];

Objective-C

57

BECOME AN XCODER 9

"
" polymorphism object-oriented programming

run-time

GUI setIntValue:

58

BECOME AN XCODER 10 awakeFromNib

10
awakeFromNib
Apple

framework [12] Foundation Kit
Application Kit

GUI

nib nib Next Interface Buil-
der Application Kit
Xcode Help Documentation

Full-Text Search
Full-Text Search Ap-
plication Kit Return Xcode Applica-
tion Kit Reference for Objective-C
Protocols NSNibAwakening

NSNibAwaking
Declared in AppKit/NSNibLoading.h
Programming Topic Loading Resources

Contents:
Protocol Description
Method Types
Instance Methods

Protocol Description
This informal protocol consists of a single method, awakeFrom-
Nib. Classes can implement this method to perform final ini-
tialization of state after objects have been loaded from an
Interface Builder archive.

59

BECOME AN XCODER 10 awakeFromNib

nib

MAFoo.m [1.15]

[1]
#import "MAFoo.h"


- (IBAction)reset:(id)sender
{
[textField setIntValue:0];
}

{
}

- (void)awakeFromNib // [1.15]
{
}

@end

awakeFromNib

60

BECOME AN XCODER 11

11

C
- pointer
- Objective-C

Mac

[1]
int x = 4;

Mac
x
[1] int
x long long double

"x = 4" 4 x
x address
x
x

pointer

& x
&x

expression x evaluate x
4 &x x

[2]
int *y;

y int y
x x y

61

BECOME AN XCODER 11

[3]
y = &x;

*y

4 "x"

*y = 5

"x = 5"

1

[4]
void increment(int *y)
{
*y = *y + 1;
}

[5]
int x = 4;
increment(&x);
// x 5

62

BECOME AN XCODER 12

12

integer long float
double BOOL pointer
string NSLog()
%
%d

[1]
float piValue = 3.1416;
NSLog(@"Here are three examples of strings printed to the screen.n");
NSLog(@"Pi approximates %10.4f.n", piValue);
NSLog(@"The number of eyes of a dice is %d.n", 6);

NSString NSMutableString NSString

[2]
NSString *favoriteComputer;
favoriteComputer = @"Mac!";
NSLog(favoriteComputer);

[2.1]
11
[2]

[3]
int *y;

y [2.1]
favoriteComputer NSString
Objective-C

@ Objective-C C
C Objective-C
Objective-C @

63

BECOME AN XCODER 12

Objective-C C Objective-C Uni-
code ASCII Unicode

[4]

[4]
NSString *favoriteActress = @"Julia";

favoriteActress "Julia"

favoriteComputer
[5] NSString

[5]

int main (int argc, const char *argv[])
{

NSString *x;
x = @"iBook"; // [5.7]
x = @"MacBook Pro Intel"; //

NSLog(x);
[pool release];
return 0;
}

MacBook Pro Intel

NSString immutable

Objective-C

64

BECOME AN XCODER 12

NSMutableString

length [6]

[6]

{
int theLength;
NSString * foo;

foo = @"Julia!";
theLength = [foo length]; // [6.10]
NSLog(@"The length is %d.", theLength);

[pool release];
return 0;
}

The length is 6.

foo bar
x

[6.10] foo length length NSString

- (unsigned int)length
Returns the number of Unicode characters in the receiver.

[7]
uppercaseString
NSString

[7]

65

BECOME AN XCODER 12


{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

NSString *foo, *bar;
foo = @"Julia!";
bar = [foo uppercaseString];
NSLog(@"%@ is converted into %@.", foo, bar);

[pool release];
return 0;
}

Julia! is converted into JULIA!

NSMutableString NSMutableString
appendString:

[8]

{

NSMutableString *foo; // [8.7]
foo = [@"Julia!" mutableCopy]; // [8.8]
[foo appendString:@" I am happy"];
NSLog(@"Here is the result: %@.", foo);

[pool release];
return 0;
}

66

BECOME AN XCODER 12

Here is the result: Julia! I am happy.

[8.8] mutableCopy NSString
mutable [8.8] foo
"Julia!"

Objective-C
[8.7] Objective-
C " " " "
" "

[8.7] foo "Julia!"

"foo"

foo bar

bar = foo;

foo bar

"foo"

"bar"

foo [foo dosomething];
bar [bar dosomething];

[9]

67

BECOME AN XCODER 12

{

NSMutableString *foo = [@"Julia!" mutableCopy];
NSMutableString *bar = foo;

NSLog(@"foo points to the string: %@.", foo);
NSLog(@"bar points to the string: %@.", bar);
NSLog(@"------------------------------");

[foo appendString:@" I am happy"];

NSLog(@"foo points to the string: %@.", foo);
NSLog(@"bar points to the string: %@.", bar);

[pool release];
return 0;
}

foo points to the string: Julia!
bar points to the string: Julia!
------------------------------
foo points to the string: Julia! I am happy
bar points to the string: Julia! I am happy

8
MAFoo

68

BECOME AN XCODER 13

13

array

index
element

1
1

NSArray NSMutableArray

[NSMutableArray array]

… …
NSMutableArray

Objective-C
meta-classes
Cocoa
"+" "-" 8 [4.5]
array

array
+ (id)array

69

BECOME AN XCODER 13

Creates and returns an empty array. This method is used by mu-
table subclasses of NSArray.

See Also: + arrayWithObject:, + arrayWithObjects:

[1]

{

NSMutableArray *myArray = [NSMutableArray array];

[myArray addObject:@"first string"];
[myArray addObject:@"second string"];
[myArray addObject:@"third string"];

int count = [myArray count];

NSLog(@"There are %d elements in my array", count);

[pool release];
return 0;
}

There are 3 elements in my array

0
objectAtIndex: [2.13]

[2]

{

70

BECOME AN XCODER 13




NSString *element = [myArray objectAtIndex:0]; // [2.13]

NSLog(@"The element at index 0 in the array is: %@", element);

[pool release];
return 0;
}

The element at index 0 in the array is: first string

[3]

{



int i;
int count;

71

BECOME AN XCODER 13

for (i = 0, count = [myArray count]; i < count; i = i + 1)
{
NSString *element = [myArray objectAtIndex:i];
NSLog(@"The element at index %d in the array is: %@", i, element);
}

[pool release];
return 0;
}

The element at index 0 in the array is: first string
The element at index 1 in the array is: second string
The element at index 2 in the array is: third string

NSArray NSMutableArray

replace
replaceObjectAtIndex:withObject:

Objective-C

[4]
[myArray replaceObjectAtIndex:1 withObject:@"Hello"];

1 @"Hello"
valid

Objective-C

" " Smalltalk
Objective-C expressive
" "
Objective-C

72

BECOME AN XCODER 14

14

Mac RAM

free

destroy

Cocoa
" " retain count

1 =
3

2

3

73

BECOME AN XCODER 14

retain
release Cocoa "autore-
lease pool" release -
autorelease pool
autorelease autorelease pool release
autorelease pool
autorelease pool

Cocoa reference count-
ing 15 Cocoa
Apple Apple Cocoa
automatic garbage collection
Apple

Apple 2006 WWDC World Wide Developer Conference
2007 Xcode 3.0 automatic garbage collection
Objective-C 2.0

74

BECOME AN XCODER 15

15

Xcode Objective-C

Apple

Apple
http://www.apple.com/developer

http://osx.hyperjeff.net/reference/CocoaArticles.php
http://www.cocoadev.com
http://www.cocoabuilder.com
http://www.stepwise.com

http://lists.apple.com/mailman/listinfo/cocoa-dev cocoa-dev
mailing list
http://www.cocoabuilder.com

http://www.catb.org/~esr/faqs/smart-questions.html "How To Ask Questions The
Smart Way" " " http://mis.ndhu.edu.tw/docu/
question.htm

Cocoa Stephen Kochan Programming in Objective-C

Big Nerd Ranch Aaron Hillegass Cocoa Programming for Mac OS X
Xcode James Duncan Davidson Apple O'Reilly Cocoa
with Objective-C

Mac
Apple
http://developer.apple.com/documentation/UserExperience/Conceptual/OSXHIGuid
elines/index.html

75

BECOME AN XCODER 15

Xcode 0

Bert, Alex, Philippe.

76

Become an xcoder

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