XCODE application giving fatal error.

//
//  ViewController.swift
//  RBGSlider
//
//  Created by Kyler on 7/3/16.
//  Copyright © 2016 Kyler. All rights reserved.
//

import UIKit

class ViewController: UIViewController {

    @IBOutlet var screenView: UIView!

    var redSliderValue: Float = 50.0
    var blueSliderValue: Float = 50.0
    var greenSliderValue: Float = 50.0

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


    // Get the value of the sliders
    @IBAction func redSlider(sender: UISlider) {
        redSliderValue = sender.value
        updateScreenColor()
    }

    @IBAction func blueSlider(sender: UISlider) {
        blueSliderValue = sender.value
        updateScreenColor()
    }

    @IBAction func greenSlider(sender: UISlider) {
        greenSliderValue = sender.value
        updateScreenColor()
    }

    // Helper functions
    func updateScreenColor() {
        screenView.backgroundColor = UIColor(colorLiteralRed: redSliderValue, green: greenSliderValue, blue: blueSliderValue, alpha: 1)
    }

}