Timer App in Swift 5.

Timer.swift

//
//  Timer App
//

import Foundation

// time left to finish
var (hours, minutes, seconds) = (1, 0, 3)

// convert hours, minutes and seconds to seconds and add them together
var convert = hours * 3600 + minutes * 60 + seconds

// function that convert seconds to hours, minutes and seconds
func secondsToHrsMinSec(seconds: Int) -> (Int, Int, Int) {
    return (seconds / 3600, (seconds % 3600) / 60, seconds % 60)
}

while convert != 0 {
    // call the function
    let (h, m, s) = secondsToHrsMinSec(seconds: convert)
    // set the timer label format (hh:mm:ss)
    let format = String(format: "%02i:%02i:%02i", h, m, s)
    print(format)
    // one second delay
    sleep(1)
    // subtract one second
    convert -= 1
}

print("Ring, Ring")