simple timer in swift 4 - iOS App codez

import UIKit

class ViewController: UIViewController {

@IBOutlet weak var timerLabel: UILabel!

var timer = Timer()

var counter = 0

override func viewDidLoad() {

super.viewDidLoad()

timerLabel.text = String(counter)

// Do any additional setup after loading the view, typically from a nib.

}

@IBAction func startBtnPressed(_ sender: Any) {

timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(updateTimer), userInfo: nil, repeats: true)

}

@IBAction func pauseBtnPressed(_ sender: Any) {

timer.invalidate()

}

@IBAction func restartBtnPressed(_ sender: Any) {

counter = 0

timer.invalidate()

timerLabel.text = String(counter)

}

@objc func updateTimer() {

counter = counter+1

timerLabel.text = String(counter)

}