global variable concept in iphone example

ip6AppDelegate.h

@class ip6ViewController;

@interface ip6AppDelegate : UIResponder <UIApplicationDelegate>

{

    BOOL myAppDelVar;

    int myAppDelVar2;

}

@property (nonatomic, readwrite) BOOL myAppDelVar;

@property (nonatomic, readwrite) int myAppDelVar2;

ip6AppDelegate.m

#import "ip6AppDelegate.h"

#import "ip6ViewController.h"

@synthesize myAppDelVar, myAppDelVar2;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions

{

    myAppDelVar = 0;

    myAppDelVar2 = 1;

   

    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];

    // Override point for customization after application launch.

    self.viewController = [[ip6ViewController alloc] initWithNibName:@"ip6ViewController" bundle:nil];

    self.window.rootViewController = self.viewController;

    [self.window makeKeyAndVisible];

    return YES;

}

ip6ViewController.h

#import <UIKit/UIKit.h>

extern int myGlobal;

@class ip6AppDelegate;

@interface ip6ViewController : UIViewController

{

    ip6AppDelegate *appDelObj;

}

- (IBAction)clickBtnPressed:(id)sender;

@end

ip6ViewController.m

#import "ip6ViewController.h"

#import "ip6AppDelegate.h"

#import "ip6View2.h"

@implementation ip6ViewController

int myGlobal;

- (IBAction)clickBtnPressed:(id)sender

{

    ip6View2 *ip6View2VC = [[ip6View2 alloc] initWithNibName:@"ip6View2" bundle:nil];

   

    [self presentViewController:ip6View2VC animated:YES completion:nil];

}

- (void)viewDidLoad

{

    [super viewDidLoad];

    appDelObj = (ip6AppDelegate *)[[UIApplication sharedApplication] delegate];

   

    appDelObj.myAppDelVar = 1;

    appDelObj.myAppDelVar2 = 100;

   

    NSLog(@"AppDelVars: %d, %d", appDelObj.myAppDelVar, appDelObj.myAppDelVar2);

   

    myGlobal = 100;

}

- (void)viewWillAppear:(BOOL)animated

{

    NSLog(@"%d", myGlobal);

}

ip6View2.h

- (IBAction)back:(id)sender;

ip6View2.m

#import "ip6View2.h"

#import "ip6ViewController.h"

- (IBAction)back:(id)sender

{

    [self dismissViewControllerAnimated:YES completion:nil];

}

- (void)viewDidLoad

{

    [super viewDidLoad];

   

    myGlobal = 101;

}