What components and structures are initialized when a software application starts?

When launching an iOS application, several key components and structures are initialized:

• UIApplication — the main application object that manages its lifecycle.
• AppDelegate — the application delegate that receives lifecycle events (launch, background, termination).
• UIWindow — the window that displays the user interface.
• ViewControllers — controllers that manage the application's screens.

First, the UIApplication object is created, then the application(_:didFinishLaunchingWithOptions:) method is called in the AppDelegate, where the initial interface and other services are usually configured. After that, the window becomes key and visible, and the root controller is displayed.