UIVCRVC.swift

import UIKit

class ViewController: UIViewController {
  var labelText = UILabel(frame: .zero)
  override func viewDidLoad() {
    super.viewDidLoad()
    view.addSubview(labelText)
    labelText.translatesAutoresizingMaskIntoConstraints = false
    NSLayoutConstraint.activate([
      labelText.centerYAnchor.constraint(equalTo: view.centerYAnchor),
      labelText.centerXAnchor.constraint(equalTo: view.centerXAnchor)
    ])
  }
}