Timer App iOS problem

@IBOutlet weak var timerCountdownLabel: UILabel!
@IBAction func timerCountdownSlider(_ sender: UISlider) {
    timerCountdownLabel.text = "\(Int(sender.value))"
}

@IBOutlet weak var timerLabel: UILabel!
@IBOutlet weak var tableView: UITableView!

var totalSeconds: Float = 0
var timer = Timer()
var lapTimeArray = [String]()
var audioPlayer = AVAudioPlayer()
var timerIsRunning = false



override func viewDidLoad() {
    super.viewDidLoad()
    do {
        let audioPath = Bundle.main.path(forResource: "Alarm", ofType: ".mp3")
        try audioPlayer = AVAudioPlayer(contentsOf: URL(fileURLWithPath: audioPath!))
    }
    catch {
        //ERROR
    }

}

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

// MARK: - Button Functions
//Start Button
@IBAction func startButtonDidTouch(_ sender: Any) {
    print("start Tapped")
    if !timerIsRunning{
        timer = Timer.scheduledTimer(timeInterval: 0.01, target: self, selector: #selector(self.updateTimer), userInfo: nil, repeats: true)
        timerIsRunning = true

    }


}
//Stop Button Method
@IBAction func stopButtonDidTouch(_ sender: Any) {
    if timerIsRunning{

        timer.invalidate()
        timerIsRunning = false
        audioPlayer.stop()
    }else{

        audioPlayer.stop()
    }


}
//Reset button Method
@IBAction func resetButtonDidTouch(_ sender: Any) {
    totalSeconds = 0
    timerLabel.text = "00:00:00"
    lapTimeArray = []
    tableView.reloadData()


}


//Time-in button Method
@IBAction func lapButtonDidTouch(_ sender: Any) {

    lapTimeArray.append(timerLabel.text!)
    tableView.reloadData()
    print("lap Tapped")
}


//MARK: Update Timer Method
@objc func updateTimer() {
    totalSeconds += 0.01
    let totalSecondsTimes100: Int  = Int(totalSeconds*100)

    let minutes = Int(totalSeconds/60)
    let timerChoice = Double(minutes) + 0.1


    //formats timer digit sequence
    let minStr = (minutes == 0) ? "00" : "0\(minutes)"
    let secStr = (totalSeconds < 9) ? "0\(Float(totalSecondsTimes100)/100)" : "\(Float(totalSecondsTimes100)/100)"


    switch Int(timerChoice) {
    case Int(timerCountdownLabel.text!)!:
        timerLabel.text = "\(minStr):\(secStr)"
        audioPlayer.play()
        timer.invalidate()
        timerIsRunning = false

    default:
        timerLabel.text = "\(minStr):\(secStr)"
       }

}


//MARK: - Methods for table view - required
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "lapRecordCell")
    cell?.textLabel?.text = lapTimeArray[indexPath.row]
    return cell!
}

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return lapTimeArray.count

}