NEL FILE .H
#import <UIKit/UIKit.h>


@interface ViewController : UIViewController
@property (weak, nonatomic) IBOutletUILabel *nLabel;
- (IBAction)numeroid)sender;
@property (weak, nonatomic) IBOutletUIButton *button;




@end

NEL FILE .M
#import "ViewController.h"


@interfaceViewController ()


@end


@implementation ViewController
@synthesize nLabel,button;


- (void)viewDidLoad {
[superviewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}


- (void)didReceiveMemoryWarning {
[superdidReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}


- (IBAction)numeroid)sender {
if ( [nLabel.textisEqualToString:@"0"] )
{
nLabel.text = button.titleLabel.text;
}else{
nLabel.text = [NSStringstringWithFormat:@"%@%@", nLabel.text, button.titleLabel.text];
}
}