Arrays 将更改的数组重置为其原始值

我有一个数组。我需要使用随机数生成器循环遍历所有数组元素，并且不希望重复

刚开始编码时，我即兴使用数组元素值，使用后将其设置为“”

再次选择数组元素时，我会检查新数组的数组元素值是否等于原始数组。如果没有，我输入一个新的随机索引号，然后重试

---

这可以通过以下两种方式工作，直到重新启动（startover（））

然而

''当我设置remainingQuestions=allQuestions-时，它在重新启动后不起作用。Result=每次重新启动时文本的（“/blank）”值的数量都会增加

''当我设置remainingQuestions=questionBank（）-时，它总是起作用

---

但是为什么我会做一些不同的事情。您的示例中缺少很多代码，因此需要进行一些更改，但要点如下：

import UIKit

class Question {

  let questionText : String
  let answer : Bool

  init(text: String, correctAnswer: Bool) {
    questionText = text
    answer = correctAnswer
  }
}

//Model: File - QuestionBank --------------------------------------

class QuestionBank {
  var list = [Question]()

  init() {
    list.append(Question(text: "", correctAnswer: false))
  }

  init(list: [Question]) {
    self.list = list
  }

  func pop() -> Question? {
    guard list.count > 0 else {
      return nil
    }
    return list.removeFirst()
  }
}



//Controller: File - ViewController -------------------------------

var remainingQuestions = QuestionBank()
var allQuestions = QuestionBank()

//Iteration snippet: ------------------------------------------

func answerPressed() {
  nextQuestion()
}

func nextQuestion() {
  guard let nextQuestion = remainingQuestions.pop() else {
      print("no questions left")
      startOver()
      return
  }
      questionLabel.text = nextQuestion.questionText
  }

  func startOver() {//also call on first setup
    remainingQuestions = QuestionBank(list: allQuestions.list.shuffled())

    nextQuestion()
  }

---

给你一个洗牌数组的实际例子

在任何视图控制器中的

viewDidLoad（）

中添加此项：

let questions:[String] = [
    "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten"
]
for _ in 1...4 {
    let shuffledQuestions:[String] = questions.shuffled()
    print(shuffledQuestions)
}

运行此命令时，您将在调试控制台中看到问题数组输出四次，每次都是随机顺序。它看起来像这样：

["Six", "Nine", "One", "Five", "Four", "Two", "Ten", "Three", "Eight", "Seven"]
["Two", "Nine", "Seven", "Four", "Six", "Five", "Eight", "One", "Three", "Ten"]
["Nine", "Ten", "Four", "Two", "One", "Five", "Eight", "Three", "Six", "Seven"]
["Six", "Three", "Seven", "One", "Five", "Two", "Eight", "Nine", "Four", "Ten"]

当然，每次运行它时，顺序都会有所不同

所以，这里有一个完整的10个问题的真/假测验的例子，问题顺序是随机的（随机的）。回答第10个问题后，您可以点击“重新启动测验”按钮，您将得到相同的10个问题，但顺序不同：

//Model: File - Question ------------------------------------------

class Question {

    var questionText : String
    let answer : Bool

    init(text: String, correctAnswer: Bool) {
        questionText = text
        answer = correctAnswer
    }
}

//Model: File - QuestionBank --------------------------------------

class QuestionBank {
    var list: [Question] = [
        Question(text: "One is an Even number?",   correctAnswer: false),
        Question(text: "Two is an Even number?",   correctAnswer: true),
        Question(text: "Three is an Even number?", correctAnswer: false),
        Question(text: "Four is an Even number?",  correctAnswer: true),
        Question(text: "Five is an Even number?",  correctAnswer: false),
        Question(text: "Six is an Even number?",   correctAnswer: true),
        Question(text: "Seven is an Even number?", correctAnswer: false),
        Question(text: "Eight is an Even number?", correctAnswer: true),
        Question(text: "Nine is an Even number?",  correctAnswer: false),
        Question(text: "Ten is an Even number?",   correctAnswer: true),
    ]
}

class RandomizeQuestionsViewController: UIViewController {

    let questionHeaderLabel: UILabel = {
        let v = UILabel()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.backgroundColor = .cyan
        v.numberOfLines = 0
        v.textAlignment = .center
        return v
    }()

    let questionLabel: UILabel = {
        let v = UILabel()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.backgroundColor = .yellow
        v.numberOfLines = 0
        v.textAlignment = .center
        return v
    }()

    let answerLabel: UILabel = {
        let v = UILabel()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.backgroundColor = .yellow
        v.numberOfLines = 0
        v.textAlignment = .center
        return v
    }()

    let nextButton: UIButton = {
        let v = UIButton()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.backgroundColor = .blue
        v.setTitle("Next Question", for: .normal)
        return v
    }()

    let restartButton: UIButton = {
        let v = UIButton()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.backgroundColor = .red
        v.setTitle("Restart Quiz", for: .normal)
        return v
    }()

    let trueButton: UIButton = {
        let v = UIButton()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.backgroundColor = UIColor(white: 0.9, alpha: 1.0)
        v.setTitleColor(.lightGray, for: .disabled)
        v.setTitleColor(.blue, for: .normal)
        v.layer.borderColor = UIColor.red.cgColor
        v.setTitle("True", for: .normal)
        return v
    }()

    let falseButton: UIButton = {
        let v = UIButton()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.backgroundColor = UIColor(white: 0.9, alpha: 1.0)
        v.setTitleColor(.blue, for: .normal)
        v.setTitleColor(.lightGray, for: .disabled)
        v.layer.borderColor = UIColor.red.cgColor
        v.setTitle("False", for: .normal)
        return v
    }()


    var shuffledQuestions: [Question] = [Question]()

    // arrays are zero-based
    var currentQuestionIndex: Int = 0

    override func viewDidLoad() {
        super.viewDidLoad()

        // add UI elements
        view.addSubview(questionHeaderLabel)
        view.addSubview(questionLabel)
        view.addSubview(trueButton)
        view.addSubview(falseButton)
        view.addSubview(answerLabel)
        view.addSubview(nextButton)
        view.addSubview(restartButton)

        NSLayoutConstraint.activate([

            questionHeaderLabel.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 40.0),
            questionHeaderLabel.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor, constant: 40.0),
            questionHeaderLabel.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor, constant: -40.0),
            questionHeaderLabel.heightAnchor.constraint(equalToConstant: 30.0),

            questionLabel.topAnchor.constraint(equalTo: questionHeaderLabel.bottomAnchor, constant: 0.0),
            questionLabel.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor, constant: 40.0),
            questionLabel.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor, constant: -40.0),
            questionLabel.heightAnchor.constraint(equalToConstant: 80.0),

            trueButton.topAnchor.constraint(equalTo: questionLabel.bottomAnchor, constant: 40.0),
            trueButton.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: -60.0),
            trueButton.widthAnchor.constraint(equalToConstant: 90.0),

            falseButton.topAnchor.constraint(equalTo: questionLabel.bottomAnchor, constant: 40.0),
            falseButton.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: 60.0),
            falseButton.widthAnchor.constraint(equalToConstant: 90.0),

            answerLabel.topAnchor.constraint(equalTo: trueButton.bottomAnchor, constant: 40.0),
            answerLabel.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor, constant: 40.0),
            answerLabel.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor, constant: -40.0),
            answerLabel.heightAnchor.constraint(equalToConstant: 80.0),

            nextButton.topAnchor.constraint(equalTo: answerLabel.bottomAnchor, constant: 40.0),
            nextButton.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: 0.0),
            nextButton.widthAnchor.constraint(equalToConstant: 160.0),

            restartButton.topAnchor.constraint(equalTo: answerLabel.bottomAnchor, constant: 40.0),
            restartButton.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: 0.0),
            restartButton.widthAnchor.constraint(equalToConstant: 160.0),

            ])

        trueButton.addTarget(self, action: #selector(trueTapped(_:)), for: .touchUpInside)
        falseButton.addTarget(self, action: #selector(falseTapped(_:)), for: .touchUpInside)
        nextButton.addTarget(self, action: #selector(nextQuestionTapped(_:)), for: .touchUpInside)
        restartButton.addTarget(self, action: #selector(restartQuizTapped(_:)), for: .touchUpInside)

        restartQuizTapped(nil)

    }

    @objc func restartQuizTapped(_ sender: Any?) -> Void {

        // hide restart button
        restartButton.isHidden = true

        // nextQuestion func increments the index...
        // set it to -1 so the first question will be index 0
        currentQuestionIndex = -1

        // shuffle the questions
        shuffledQuestions = QuestionBank().list.shuffled()

        // show the question
        nextQuestionTapped(nil)

    }

    @objc func nextQuestionTapped(_ sender: Any?) -> Void {

        // hide next button
        nextButton.isHidden = true

        // reset true/false button borders
        trueButton.layer.borderWidth = 0
        falseButton.layer.borderWidth = 0

        // increment the index
        currentQuestionIndex += 1

        if currentQuestionIndex < shuffledQuestions.count {

            // get current Question object from shuffled array
            let q: Question = shuffledQuestions[currentQuestionIndex]

            // set the label texts
            questionHeaderLabel.text = "Question \(currentQuestionIndex + 1) of \(shuffledQuestions.count)"
            questionLabel.text = q.questionText
            answerLabel.text = "Select True or False"

            // enable true/false buttons
            trueButton.isEnabled = true
            falseButton.isEnabled = true

        } else {

            // out of questions, so show restart button
            restartButton.isHidden = false

        }

    }

    @objc func trueTapped(_ sender: Any?) -> Void {

        // highlight selected button
        trueButton.layer.borderWidth = 3

        // get current Question object from shuffled array
        let q: Question = shuffledQuestions[currentQuestionIndex]

        var answerText = ""

        if q.answer == true {
            answerText = "Correct!" + "\n" + "It IS an Even number!"
        } else {
            answerText = "Wrong!" + "\n" + "It is NOT an Even number!"
        }

        updateUI(feedback: answerText)

    }

    @objc func falseTapped(_ sender: Any?) -> Void {

        // highlight selected button
        falseButton.layer.borderWidth = 3

        // get current Question object from shuffled array
        let q: Question = shuffledQuestions[currentQuestionIndex]

        var answerText = ""

        if q.answer == false {
            answerText = "Correct!" + "\n" + "It is NOT an Even number!"
        } else {
            answerText = "Wrong!" + "\n" + "It IS an Even number!"
        }

        updateUI(feedback: answerText)

    }

    func updateUI(feedback answer: String) -> Void {

        answerLabel.text = answer

        // disable true/false buttons
        trueButton.isEnabled = false
        falseButton.isEnabled = false

        // if there are more questions
        if currentQuestionIndex < shuffledQuestions.count - 1 {
            // show next question button
            nextButton.isHidden = false
        } else {
            // show restart button
            restartButton.isHidden = false
        }

    }

}

//模型：文件-问题------------------------------------------
课堂提问{
变量文本：字符串
让我们回答：布尔
初始化（文本：字符串，正确答案：Bool）{
问题文本=文本
答案=正确答案
}
}
//模型：文件库--------------------------------------
班级问题库{
变量列表：[问题]=[
问题（正文：“一是偶数？”，正确答案：假），
问题（文本：“2是偶数？”，正确答案：真），
问题（正文：“三是偶数？”，正确答案：错），
问题（正文：“四是偶数？”，正确答案：正确），
问题（文本：“五是偶数？”，正确答案：错），
问题（正文：“六是偶数？”，正确答案：正确），
问题（文本：“七是偶数？”，正确答案：错），
问题（正文：“八是偶数？”，正确答案：正确），
问题（文本：“九是偶数？”，正确答案：错），
问题（文本：“十是偶数？”，正确答案：正确），
]
}
类RandomizeQuestionViewController:UIViewController{
let questionHeaderLabel:UILabel={
设v=UILabel（）
v、 translatesAutoresizingMaskIntoConstraints=false
v、 背景色=.cyan
v、 numberOfLines=0
v、 textAlignment=.center
返回v
}()
let questionLabel:UILabel={
设v=UILabel（）
v、 translatesAutoresizingMaskIntoConstraints=false
v、 背景颜色=.黄色
v、 numberOfLines=0
v、 textAlignment=.center
返回v
}()
让应答器标签：UILabel={
设v=UILabel（）
v、 translatesAutoresizingMaskIntoConstraints=false
v、 背景颜色=.黄色
v、 numberOfLines=0
v、 textAlignment=.center
返回v
}()
let nextButton:ui按钮={
设v=UIButton（）
v、 translatesAutoresizingMaskIntoConstraints=false
v、 背景颜色=.blue
v、 setTitle（“下一个问题”，用于：。正常）
返回v
}()
让重新启动按钮：UIButton={
设v=UIButton（）
v、 translatesAutoresizingMaskIntoConstraints=false
v、 背景颜色=.red
v、 setTitle（“重启测验”，用于：。正常）
返回v
}()
让trueButton:UIButton={
设v=UIButton（）
v、 translatesAutoresizingMaskIntoConstraints=false
v、 backgroundColor=UIColor（白色：0.9，alpha:1.0）
v、 setTitleColor（.lightGray，用于：。已禁用）
v、 setTitleColor（.blue，表示：。正常）
v、 layer.borderColor=UIColor.red.cgColor
v、 setTitle（“True”，表示：。正常）
返回v
}()
let falseButton:UIButton={
设v=UIButton（）
v、 translatesAutoresizingMaskIntoConstraints=false
v、 backgroundColor=UIColor（白色：0.9，alpha:1.0）
v、 setTitleColor（.blue，表示：。正常）
v、 setTitleColor（.lightGray，用于：。已禁用）
v、 layer.borderColor=UIColor.red.cgColor
v、 setTitle（“False”，用于：。正常）
返回v
}()
var shuffledQuestions:[问题]=[问题]（）
//数组是零基的
var currentQuestionIndex:Int=0
重写func viewDidLoad（）{
super.viewDidLoad（）
//添加UI元素
view.addSubview（问题标题标签）
view.addSubview（问题标签）
view.addSubview（trueButton）
view.addSubview（错误按钮）
view.addSubview（应答标签）
view.addSubview（下一个按钮）
view.addSubview（重新启动按钮）
NSLayoutConstraint.activate([
questionHeaderLabel.topAnchor.constraint（等式：view.safeAreaLayoutGuide.topAnchor，常量：40.0），
问题标题标记.引导锚定约束（等于：view.SafeArealLayoutGuide.leadingAnchor，常量：40.0），
questionHeaderLabel.trailingAnchor.constraint（等式：view.safeArea LayoutGuide.trailingAnchor，常数：-40.0），
questionHeaderLabel.heightAnchor.constraint（等式常量：30.0），
questionLabel.topAnchor.constraint（等式：questionHeaderLabel.bottomAnchor，常量：0.0），
问题标签.leadingAnchor.constraint（等式：view.SafeArealLayoutGuide.leadingAnchor，Constant
//Model: File - Question ------------------------------------------

class Question {

    var questionText : String
    let answer : Bool

    init(text: String, correctAnswer: Bool) {
        questionText = text
        answer = correctAnswer
    }
}

//Model: File - QuestionBank --------------------------------------

class QuestionBank {
    var list: [Question] = [
        Question(text: "One is an Even number?",   correctAnswer: false),
        Question(text: "Two is an Even number?",   correctAnswer: true),
        Question(text: "Three is an Even number?", correctAnswer: false),
        Question(text: "Four is an Even number?",  correctAnswer: true),
        Question(text: "Five is an Even number?",  correctAnswer: false),
        Question(text: "Six is an Even number?",   correctAnswer: true),
        Question(text: "Seven is an Even number?", correctAnswer: false),
        Question(text: "Eight is an Even number?", correctAnswer: true),
        Question(text: "Nine is an Even number?",  correctAnswer: false),
        Question(text: "Ten is an Even number?",   correctAnswer: true),
    ]
}

class RandomizeQuestionsViewController: UIViewController {

    let questionHeaderLabel: UILabel = {
        let v = UILabel()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.backgroundColor = .cyan
        v.numberOfLines = 0
        v.textAlignment = .center
        return v
    }()

    let questionLabel: UILabel = {
        let v = UILabel()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.backgroundColor = .yellow
        v.numberOfLines = 0
        v.textAlignment = .center
        return v
    }()

    let answerLabel: UILabel = {
        let v = UILabel()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.backgroundColor = .yellow
        v.numberOfLines = 0
        v.textAlignment = .center
        return v
    }()

    let nextButton: UIButton = {
        let v = UIButton()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.backgroundColor = .blue
        v.setTitle("Next Question", for: .normal)
        return v
    }()

    let restartButton: UIButton = {
        let v = UIButton()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.backgroundColor = .red
        v.setTitle("Restart Quiz", for: .normal)
        return v
    }()

    let trueButton: UIButton = {
        let v = UIButton()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.backgroundColor = UIColor(white: 0.9, alpha: 1.0)
        v.setTitleColor(.lightGray, for: .disabled)
        v.setTitleColor(.blue, for: .normal)
        v.layer.borderColor = UIColor.red.cgColor
        v.setTitle("True", for: .normal)
        return v
    }()

    let falseButton: UIButton = {
        let v = UIButton()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.backgroundColor = UIColor(white: 0.9, alpha: 1.0)
        v.setTitleColor(.blue, for: .normal)
        v.setTitleColor(.lightGray, for: .disabled)
        v.layer.borderColor = UIColor.red.cgColor
        v.setTitle("False", for: .normal)
        return v
    }()


    var shuffledQuestions: [Question] = [Question]()

    // arrays are zero-based
    var currentQuestionIndex: Int = 0

    override func viewDidLoad() {
        super.viewDidLoad()

        // add UI elements
        view.addSubview(questionHeaderLabel)
        view.addSubview(questionLabel)
        view.addSubview(trueButton)
        view.addSubview(falseButton)
        view.addSubview(answerLabel)
        view.addSubview(nextButton)
        view.addSubview(restartButton)

        NSLayoutConstraint.activate([

            questionHeaderLabel.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 40.0),
            questionHeaderLabel.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor, constant: 40.0),
            questionHeaderLabel.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor, constant: -40.0),
            questionHeaderLabel.heightAnchor.constraint(equalToConstant: 30.0),

            questionLabel.topAnchor.constraint(equalTo: questionHeaderLabel.bottomAnchor, constant: 0.0),
            questionLabel.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor, constant: 40.0),
            questionLabel.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor, constant: -40.0),
            questionLabel.heightAnchor.constraint(equalToConstant: 80.0),

            trueButton.topAnchor.constraint(equalTo: questionLabel.bottomAnchor, constant: 40.0),
            trueButton.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: -60.0),
            trueButton.widthAnchor.constraint(equalToConstant: 90.0),

            falseButton.topAnchor.constraint(equalTo: questionLabel.bottomAnchor, constant: 40.0),
            falseButton.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: 60.0),
            falseButton.widthAnchor.constraint(equalToConstant: 90.0),

            answerLabel.topAnchor.constraint(equalTo: trueButton.bottomAnchor, constant: 40.0),
            answerLabel.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor, constant: 40.0),
            answerLabel.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor, constant: -40.0),
            answerLabel.heightAnchor.constraint(equalToConstant: 80.0),

            nextButton.topAnchor.constraint(equalTo: answerLabel.bottomAnchor, constant: 40.0),
            nextButton.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: 0.0),
            nextButton.widthAnchor.constraint(equalToConstant: 160.0),

            restartButton.topAnchor.constraint(equalTo: answerLabel.bottomAnchor, constant: 40.0),
            restartButton.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: 0.0),
            restartButton.widthAnchor.constraint(equalToConstant: 160.0),

            ])

        trueButton.addTarget(self, action: #selector(trueTapped(_:)), for: .touchUpInside)
        falseButton.addTarget(self, action: #selector(falseTapped(_:)), for: .touchUpInside)
        nextButton.addTarget(self, action: #selector(nextQuestionTapped(_:)), for: .touchUpInside)
        restartButton.addTarget(self, action: #selector(restartQuizTapped(_:)), for: .touchUpInside)

        restartQuizTapped(nil)

    }

    @objc func restartQuizTapped(_ sender: Any?) -> Void {

        // hide restart button
        restartButton.isHidden = true

        // nextQuestion func increments the index...
        // set it to -1 so the first question will be index 0
        currentQuestionIndex = -1

        // shuffle the questions
        shuffledQuestions = QuestionBank().list.shuffled()

        // show the question
        nextQuestionTapped(nil)

    }

    @objc func nextQuestionTapped(_ sender: Any?) -> Void {

        // hide next button
        nextButton.isHidden = true

        // reset true/false button borders
        trueButton.layer.borderWidth = 0
        falseButton.layer.borderWidth = 0

        // increment the index
        currentQuestionIndex += 1

        if currentQuestionIndex < shuffledQuestions.count {

            // get current Question object from shuffled array
            let q: Question = shuffledQuestions[currentQuestionIndex]

            // set the label texts
            questionHeaderLabel.text = "Question \(currentQuestionIndex + 1) of \(shuffledQuestions.count)"
            questionLabel.text = q.questionText
            answerLabel.text = "Select True or False"

            // enable true/false buttons
            trueButton.isEnabled = true
            falseButton.isEnabled = true

        } else {

            // out of questions, so show restart button
            restartButton.isHidden = false

        }

    }

    @objc func trueTapped(_ sender: Any?) -> Void {

        // highlight selected button
        trueButton.layer.borderWidth = 3

        // get current Question object from shuffled array
        let q: Question = shuffledQuestions[currentQuestionIndex]

        var answerText = ""

        if q.answer == true {
            answerText = "Correct!" + "\n" + "It IS an Even number!"
        } else {
            answerText = "Wrong!" + "\n" + "It is NOT an Even number!"
        }

        updateUI(feedback: answerText)

    }

    @objc func falseTapped(_ sender: Any?) -> Void {

        // highlight selected button
        falseButton.layer.borderWidth = 3

        // get current Question object from shuffled array
        let q: Question = shuffledQuestions[currentQuestionIndex]

        var answerText = ""

        if q.answer == false {
            answerText = "Correct!" + "\n" + "It is NOT an Even number!"
        } else {
            answerText = "Wrong!" + "\n" + "It IS an Even number!"
        }

        updateUI(feedback: answerText)

    }

    func updateUI(feedback answer: String) -> Void {

        answerLabel.text = answer

        // disable true/false buttons
        trueButton.isEnabled = false
        falseButton.isEnabled = false

        // if there are more questions
        if currentQuestionIndex < shuffledQuestions.count - 1 {
            // show next question button
            nextButton.isHidden = false
        } else {
            // show restart button
            restartButton.isHidden = false
        }

    }

}