arc4random_uniform

@IBAction func getOmikuji(sender: AnyObject) {
        // 0 - n
        // arc4random_uniform(n + 1)
        let random = arc4random_uniform(10)
        
        self.myLabel.text = String(random)
    }

おーおーお

@IBOutlet weak var myLabel: UILabel!
    
    @IBAction func getOmikuji(sender: AnyObject) {
        // 0 - n
        // arc4random_uniform(n + 1)
        let results = ["大吉", "中吉","吉", "大凶"]
        let random = arc4random_uniform(UInt32(results.count))
        
        self.myLabel.text = results[Int(random)]
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
//        myLabel.layer.borderColor = UIColor.orange.cgColor
//        myLabel.layer.borderWidth = 5
//        myLabel.layer.cornerRadius = 50
        myLabel.layer.masksToBounds = true
        myLabel.layer.cornerRadius = myLabel.bounds.width / 2
        
        
        // Do any additional setup after loading the view, typically from a nib.
    }