What methods are used to implement user interface layout in UIKit?

In UIKit, user interface layout can be implemented using the following methods:

1. Storyboard — a visual editor where the interface is created via drag-and-drop, and connections between screens and elements are set graphically.

2. XIB (Nib) files — separate interface files created in Interface Builder and loaded programmatically.

3. Programmatically (code) — creating and configuring UI elements in Swift or Objective-C code, providing full control over the interface.

4. SwiftUI — a modern declarative framework from Apple for describing UI, which can be used alongside UIKit.

Example of programmatically creating a button in UIKit using Swift:

let button = UIButton(type: .system)
button.setTitle("Press me", for: .normal)
button.frame = CGRect(x: 50, y: 100, width: 100, height: 50)
view.addSubview(button)