Hands-On Design Patterns with Swift

The model layer

The model layer of our application will contain the following:

• The Question structure, responsible for holding the question string, as well as the expected answer (true/false)
• The QuestionController class, responsible for loading the questions as well as advancing to the next question:

// Question.swiftenum BooleanAnswer: String {    case `true`    case `false`}struct Question {    let question: String    let answer: BooleanAnswer}extension Question {    func isGoodAnswer(result: String?) -> Bool {       return result == answer.rawValue    }}// QuestionController.swiftclass QuestionController {    private var questions = [Question]()    // Load the questions from memory or disk    func load() { /* load from disk, memory or else */ } // Get the next question, ...