xcode界面按钮点完之后为什么label栏里没有反应

我很烦恼这个问题，比如我现在设计了1这个按钮，然后在模拟器中运行，为什么显示点1label栏没有显示呢，我连接label栏的代码是这样的：
@property (strong,nonatomic) IBOutlet UILabel * display;
我所有的代码是这样的：

#import
@interface HelloViewController : UIViewController
@property (strong,nonatomic) IBOutlet UILabel * display;
-(IBAction) anjian1;
-(IBAction) jia;
@end
#import \\"HelloViewController.h\\"
@interface HelloViewController ()
@end
@implementation HelloViewController
@synthesize display;

• (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib. }
• (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated. } -(IBAction) anjian1{ display.text=@\\"1\\"; } -(IBAction) jia{ display.text=@\\"+\\"; } @end