In what situations is it appropriate to apply the MVC architectural pattern?

MVC is suitable for projects with relatively simple UI and logic, where flexibility and testability are secondary to development speed and ease of understanding.

The use of MVC can be justified in the following cases:

• Projects with a short lifecycle or MVP (Minimum Viable Product).
• Small applications with a limited number of screens.
• Teams with limited experience in more complex architectures.

Problems of MVC in large projects:

• "Massive View Controller": The View Controller becomes too large and contains a lot of logic, making it difficult to maintain and test.
• Weak separation of concerns: The View Controller often takes on too many roles (handling UI, business logic, interaction with the model).
• Testing complexity: Logic is mixed with UI, which makes unit testing difficult.

// Example of a simple MVC implementation
class ViewController: UIViewController {
    var model: DataModel!
    @IBOutlet weak var dataLabel: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()
        model = DataModel()
        updateUI()
    }

    func updateUI() {
        dataLabel.text = model.data
    }

    @IBAction func buttonTapped(_ sender: Any) {
        model.updateData()
        updateUI()
    }
}

class DataModel {
    var data: String = "Initial Data"

    func updateData() {
        data = "Updated Data"
    }
}

In more complex projects, it is preferable to use architectural patterns such as MVVM, VIPER, or RIBs, which provide better separation of responsibilities, improve testability, and scalability.