play the game twenty questions in swift

main.swift
import UIKit

class ViewController: UIViewController {

    let questions = [
        "Is it an animal?",
        "Is it a type of food?",
        "Is it a plant?",
        "Is it larger than a car?",
        "Is it smaller than a pencil?",
        "Can it fly?",
        "Is it a household item?",
        "Is it found outdoors?",
        "Is it typically man-made?",
        "Is it a type of clothing?",
        "Is it round?",
        "Is it a type of vehicle?",
        "Is it a musical instrument?",
        "Is it a type of sports equipment?",
        "Is it typically used indoors?",
        "Is it a type of toy?",
        "Is it a type of technology?",
        "Is it a type of furniture?",
        "Is it a type of appliance?",
        "Is it a type of plant?"
    ]

    var currentQuestionIndex = 0
    var yesAnswers = [Bool]()

    let maxNumberOfQuestions = 20

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        askQuestion(index: currentQuestionIndex)
    }

    func askQuestion(index: Int) {
        if index >= maxNumberOfQuestions {
            showResult()
            return
        }

        let alert = UIAlertController(title: "Question \(index + 1)", message: questions[index], preferredStyle: .alert)

        alert.addAction(UIAlertAction(title: "Yes", style: .default, handler: { action in
            self.yesAnswers.append(true)
            self.currentQuestionIndex += 1
            self.askQuestion(index: self.currentQuestionIndex)
        }))

        alert.addAction(UIAlertAction(title: "No", style: .default, handler: { action in
            self.yesAnswers.append(false)
            self.currentQuestionIndex += 1
            self.askQuestion(index: self.currentQuestionIndex)
        }))

        self.present(alert, animated: true, completion: nil)
    }

    func showResult() {
        var guessedObject: String

        // Simple rule based decision making
        if yesAnswers[0] == true && yesAnswers[1] == true && yesAnswers[2] == true {
            guessedObject = "dog"
        } else if yesAnswers[1] == false && yesAnswers[2] == false && yesAnswers[6] == true {
            guessedObject = "chair"
        } else if yesAnswers[1] == true && yesAnswers[15] == true && yesAnswers[9] == false {
            guessedObject = "football"
        } else {
            guessedObject = "I don't know"
        }

        let alert = UIAlertController(title: "Result", message: "I guess you were thinking of a \(guessedObject)", preferredStyle: .alert)

        alert.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))

        self.present(alert, animated: true, completion: nil)
    }
}
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