Can you explain what is meant by declarative programming style?

Declarative programming is an approach where you describe what needs to be done, rather than how to do it. Unlike imperative style, where the programmer specifies detailed steps and logic, declarative focuses on the end result.

In iOS, an example of declarative style is SwiftUI — you describe the interface and its state, and the system manages the display and updates itself.

An example of declarative UI in SwiftUI:

struct ContentView: View {
    @State private var isOn = false

    var body: some View {
        Toggle("Turn on", isOn: $isOn)
            .padding()
    }
}

Here, you simply describe what the interface should display (a toggle bound to the state), and the framework takes care of how to update the screen when isOn changes.

Thus, declarative programming simplifies development, making the code more readable and maintainable.