//файл Foo.h
#import <Cocoa/Cocoa.h>

@interface Foo : NSObject
{
   NSString* str;
   static int i = 0;
}

- (NSString*) str;
@end

//Foo.m
#import "Foo.h"

@implementation
- (id) init
{
   return [self initWithStr:"number:" someInt:6];
}

- (id) initWithStr:(NSString*)theStr someInt:(int)value
{
   self = [super init];
   str = [NSString stringWithFormat:@"%@%d", theStr, value];
   return self;
}

- (NSString*) str
{
   return str;
}

- (void) setStr:(NSString*)theStr
{
   str = theStr;
}
@end

//main.m
#import <Cocoa/Cocoa.h>
#import "Foo.h"

int main(int argc, char *argv[])
{
   Foo objA;
   NSLog([objA str]);
   [objA setStr:@"hello world!"];
   NSLog([objA str]);

   Foo* objB = [[Foo alloc] init];
   Foo* objC = [[Foo alloc] initWithStr:@"My magic number:" value:265];
   objB = objC;

   NSLog([objB str]);

   [objA release];
   [objB release];
   [objC release];

   return 0;
}

(BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    
	[window makeKeyAndVisible];

	[self performSelectorInBackground:@selector(launchTimer) withObject:nil];
    
	return YES;
}

- (void)launchTimer {
	NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
	NSTimeInterval timeInterval = 3.0;
	
	self.timer = [NSTimer scheduledTimerWithTimeInterval:timeInterval
        target:self
        selector:@selector(timerFired:) 
        userInfo:[NSNumber numberWithDouble:timeInterval] repeats:NO];

	[pool release];
}

- (void)timerFired:(NSTimer *)aTimer {
	NSLog(@"User info: %@", [aTimer userInfo]);
}

#import <Foundation/Foundation.h>

@interface Foo : NSObject {
@private
	NSString * string_;
}

@property (nonatomic, readonly) NSString * string;

- (void)bar;

@end

@implementation Foo

@synthesize string = string_;

- (void)bar {
	self.string = nil;
}

- (void)dealloc {
	[string release];
	[super dealloc];
}

@end