Creating pageview showing 3 images and adding them to scroll view

example.m

#define SCROLLWIDTH 279
- (void)viewDidLoad {
    scrollView.contentSize=CGSizeMake(SCROLLWIDTH*3, 
     scrollView.frame.size.height);
    scrollView.delegate = self;
    for (int i =0; i<=3; i++) {
        UIImageView *imageView = [[UIImageView alloc]initWithFrame:
CGRectMake(SCROLLWIDTH*i, 0, scrollView.frame.size.width,
 scrollView.frame.size.height)];
        if (i==0)  {
            imageView.backgroundColor = [UIColor redColor];
        }
        else if (i==1)  {
            imageView.backgroundColor = [UIColor greenColor];
        }
        else {
            imageView.backgroundColor = [UIColor yellowColor];
        }
      [scrollView addSubview:imageView];
    }
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}