Get Programming with JavaScript - Listings 13.03 and 13.04

Listings 13.03 and 13.04 - Picking a question at random

HTML:

<!-- Number Generator -->
<script src="http://output.jsbin.com/qezoce.js"></script>

JS:

var getQuiz = function () {
    var qIndex = 0;

    var questions = [
        { question: "7 x 8", answer: "56" },
        { question: "12 x 12", answer: "144" },
        { question: "5 x 6", answer: "30" },
        { question: "9 x 3", answer: "27" }
    ];

    var getQuestion = function () {
        qIndex = between(0, questions.length - 1);
        return questions[qIndex].question;
    };

    var checkAnswer = function (userAnswer) {
        if (userAnswer === questions[qIndex].answer) {
            return "Correct!";
        } else {
            return "No, the answer is " + questions[qIndex].answer;
        }
    };

    return {
        quizMe: getQuestion,
        submit: checkAnswer
    };
};

var quiz = getQuiz();

Further Adventures

Listings 13.03 and 13.04 - Picking a question at random - Tasks 4 & 5

Update the program so that it keeps a score of correct answers.
Define a showScore function that displays the current score.

var getQuiz = function () {
    var qIndex = 0;
    var numAsked = 0;
    var numCorrect = 0;

    var questions = [
        { question: "7 x 8", answer: "56" },
        { question: "12 x 12", answer: "144" },
        { question: "5 x 6", answer: "30" },
        { question: "9 x 3", answer: "27" }
    ];

    var getQuestion = function () {
        numAsked += 1;
        qIndex = between(0, questions.length - 1);
        return questions[qIndex].question;
    };

    var checkAnswer = function (userAnswer) {
        if (userAnswer === questions[qIndex].answer) {
            numCorrect += 1;
            return "Correct!";
        } else {
            return "No, the answer is " + questions[qIndex].answer;
        }
    };

    var showScore = function () {
        return "Your score is " + numCorrect + " out of " + numAsked;
    };

    return {
        quizMe: getQuestion,
        submit: checkAnswer,
        score: showScore
    };
};

var quiz = getQuiz();