title: How to place a subview in the center of parent view using .center?
body: <p>I have two subviews: the purple one belongs to a main view and it works wonderful with the syntax:</p>
  
  <pre><code>sSubview.center = view.center 
  </code></pre>
  
  <p>The orange one belongs to the purple view and the same syntax doesn't place it correctly in the center.
  Could you see where my mistake is?</p>
  
  <pre><code>Here is my code:
  
  import UIKit
  
  class ViewController: UIViewController {
  
  var sSubview = UIView()
  var sLabel = UILabel()
  
  override func viewDidLoad() {
      super.viewDidLoad()
      // Do any additional setup after loading the view, typically from a nib.
      view.backgroundColor = UIColor.lightGray
  }
  
  override func didReceiveMemoryWarning() {
      super.didReceiveMemoryWarning()
      // Dispose of any resources that can be recreated.
  }
  
  override func viewDidLayoutSubviews() {
  
      createSimplestSubview()
  
  }
  
  // First subview
  
  func createSimplestSubview() {
   sSubview = UIView(frame: CGRect(x: 0, y: 0, width: view.frame.width * 0.9, height: view.frame.height * 0.9))
   sSubview.backgroundColor = UIColor.purple // just for test, to make it visible
   sSubview.center = view.center // that s pretty easy!
  
   view.addSubview(sSubview)
   createSimplestLabel()
   }
  
  // Second subview
  
  func createSimplestLabel() {
  
      sLabel = UILabel(frame: CGRect(x: 0, y: 0, width: sSubview.frame.width * 0.3, height: sSubview.frame.height * 0.2))
      sLabel.backgroundColor = UIColor.orange // just for test, to make it visible
      sLabel.center = sSubview.center
      sLabel.text = "This label has to be centered!"
      sLabel.textAlignment = .center
      sLabel.numberOfLines = 0
      sSubview.addSubview(sLabel)
  
  }
  </code></pre>
  
  <p>}</p>
  
  <p>Here is a screen:
  <a href="https://i.stack.imgur.com/6zRtn.png" rel="noreferrer"><img src="https://i.stack.imgur.com/6zRtn.png" alt="enter image description here"></a></p>