@interface - *.h
UIWindow *window;
@property (nonatomic, retain) IBOutlet UIWindow *window;
@implement - *.m
@synthesize window;
-(void)applicationDidReceiveMemoryWarning:(UIApplication *)application
-(void)applicationSignificantTimeChange:(UIApplication *)application
-(void)applicationWillResignActive:(UIApplication *)application
-(void)applicationDidBecomeActive:(UIApplication *)application
-(void)applicationDidEnterBackground:(UIApplication *)application
-(void)applicationWillEnterForeground:(UIApplication *)application
UIApplicationDelegate는 애플리케이션의 시작과 종료에 관련된 작업을 할 수 있다.
-(void)applicationDidFinishLaunching:(UIApplication *)application
-(void)applicationWillTerminate:(UIApplication *)application
-(void)applicationDidFinishLaunching:(UIApplication *)application
-(void)applicationWillTerminate:(UIApplication *)application
