iOS 11 Swift 4 Play sound

sound.swift

import UIKit
import AVFoundation

class ViewController: UIViewController, AVAudioPlayerDelegate{
    
    var audioPlayer: AVAudioPlayer!

    @IBAction func notePressed(_ sender: UIButton) {
        playSound("note\(sender.tag)")
    }
    
    func playSound(_ soundFile: String) {
        let soundURL = Bundle.main.url(forResource: soundFile, withExtension: "wav")
        do{
            audioPlayer = try AVAudioPlayer(contentsOf: soundURL!)
        }
        catch {
            print(error.localizedDescription)
        }
        audioPlayer.play()
    }
}