"Cannot find 'ContentView' in scope in Swift

Question

I'm just learning Swift, I created this starter project that needs UIKit, but whenever I run the code I get the following error:

"Cannot find 'ContentView' in scope in Swift

And here's the code:

import UIKit


class ViewController: UIViewController {
    
    
    private let imageView: UIImageView = {
        let imageView = UIImageView()
        imageView.contentMode = .scaleAspectFill
        imageView.backgroundColor = .white
        return imageView
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .systemPink
    }
    
    
}

Answer 1

You might need to clean the Build folder, ie, use the keyboard shortcut Shift + Command + K or via the Menu “Product > Clean Build Folder”
You might need to restart Xcode.
You might need to restart your Mac

or

Are you loading the viewcontroller in AppDelegate/SceneDelegete manulay?

class AppDelegate: UIResponder, UIApplicationDelegate {
    var window: UIWindow?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        window = UIWindow(frame: UIScreen.main.bounds)
        window?.rootViewController = ViewController()
        window?.makeKeyAndVisible()
        return true
    }

}