依類別存放檔案
1. File -> New -> File
2. Objective-C class
3. 輸入 class 名稱
4. create 確定後會產生 .m 和 .h 檔
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; NSLog(@"Hello World!"); [pool drain];
@autoreleasepool{ NSLog(@"Hello World!"); }
int UIApplicationMain ( int argc, char *argv[], NSString *principalClassName, NSString *delegateClassName );
main.main.UIApplication, you may designate the subclass as the delegate; the subclass instance receives the application-delegate messages. Specify nil if you load the delegate object from your application’s main nib file.