swiftでIBOutlet, IBAction ref: http://qiita.com/jazzsasori/items/6053e1467772b7ff9783

file0.txt

import UIKit

class ViewController: UIViewController {

    @IBOutlet var button:UIButton
    @IBAction func buttonTapped(sender:AnyObject) {
        var tappedButton:UIButton = sender as UIButton
        tappedButton.setTitle("tapped", forState:UIControlState.Normal)
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        button.setTitle("tap me", forState:UIControlState.Normal)
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }
}