// The addQuestion function allows the exam administrator to add a question to the exam function addQuestion(uint _questionNumber, string memory _question, string memory _answer) public { require(msg.sender == administrator, "Only the administrator can add questions to the exam."); require(_questionNumber > 0 && _questionNumber <= numQuestions, "Invalid question number."); require(questions[_questionNumber] == bytes32(0), "Question has already been added.");

    questions[_questionNumber] = _question;
    answers[_questionNumber] = _answer;
}

// The submitAnswers function allows a user to submit their answers to the exam
function submitAnswers(uint[] memory _answers) public {
    require(isOpen, "Exam is closed.");
    require(_answers.length == numQuestions, "Incorrect number of answers.");
    address user = msg.sender;
    Submission storage submission = submissions[user];
    submission.numAttempts++;

    require(submission.numAttempts <= maxAttempts, "Exceeded maximum number of attempts.");

    // Grade the submission
    submission.score = 0;
    for (uint i = 0; i < numQuestions; i++) {
        if (_answers[i] == uint(answers[i])) {

{submission.score++; } } // Save the submission submission.answers = _answers; }}