     }
     
     @IBAction func longPressedOutput(sender: UIGestureRecognizer) {
+        // Copy input label text to clipboard after a long press.
         if sender.state == .Began {
             UIPasteboard.generalPasteboard().string = outputCurrencyLabel.text
             print("Copied output currency value to clipboard.")

    }
    
    @IBAction func swipedInput(sender: AnyObject) {
        converter.removeLastInput()
        updateInterface()
    }
    
    @IBAction func longPressedInput(sender: UIGestureRecognizer) {
        if sender.state == .Began {
            UIPasteboard.generalPasteboard().string = inputCurrencyLabel.text
            print("Copied input currency value to clipboard.")

    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        
        // Pass the currency we are changing (input or output) and
        // the current currency code to the Change Currency View Controller.
        
        if segue.identifier == "ChangeInputCurrency" {
            let changeCurrencyViewController = (segue.destinationViewController as! UINavigationController).topViewController as! ChangeCurrencyViewController
            changeCurrencyViewController.targetCurrency = "input"
            changeCurrencyViewController.selectedCurrency = converter.inputCurrency.code
            changeCurrencyViewController.delegate = self
        }
        
        if segue.identifier == "ChangeOutputCurrency" {
            let changeCurrencyViewController = (segue.destinationViewController as! UINavigationController).topViewController as! ChangeCurrencyViewController
            changeCurrencyViewController.targetCurrency = "output"
            changeCurrencyViewController.selectedCurrency = converter.outputCurrency.code
            changeCurrencyViewController.delegate = self
        }
        
