choose_check_next.swift

    @IBAction func chooseAnswer(_ sender: UIButton) {
        let selectedAnswer = sender.currentTitle!
//        switch sender.tag {
//        case 1:
//            selectedAnswer = newQandA[questionIndex].optionA
//        case 2:
//            selectedAnswer = newQandA[questionIndex].optionB
//        case 3:
//            selectedAnswer = newQandA[questionIndex].optionC
//        case 4:
//            selectedAnswer = newQandA[questionIndex].optionD
//        default:
//            break
//        }
        if checkAnswer(userAnswer: selectedAnswer) {
            sender.backgroundColor = #colorLiteral(red: 0.4666666687, green: 0.7647058964, blue: 0.2666666806, alpha: 1)
        } else {
            sender.backgroundColor = #colorLiteral(red: 0.8078431487, green: 0.02745098062, blue: 0.3333333433, alpha: 1)
        }
        nextQuestion()
        Timer.scheduledTimer(timeInterval: 0.5, target: self, selector: #selector(showQandA), userInfo: nil, repeats: false)
    }
    
    func checkAnswer(userAnswer: String) -> Bool {
        if userAnswer == newQandA[questionIndex].answer {
            scoreNumber += 1
            return true
        } else {
            return false
        }
    }
    
    func nextQuestion() {
        if  questionIndex + 1 < newQandA.count {
            questionIndex += 1
        } else {
            performSegue(withIdentifier: "showResult", sender: ResultViewController.self)
        }
    }