quiz.js

const questions = [
    {
    question: "Who is the father of C language?", 
    answers: [
        { text: "Steve Jobs", correct: false}, 
        { text: "James Gosling", correct: false},
        {text: "Dennis Ritchie", correct: true}, 
        {text: "Rasmus Lerdorf", correct: false},
    ]
},
{
    question: "Which of the following is not a valid C variable name?", 
    answers: [
        { text: "int number;", correct: false}, 
        { text: "float rate;", correct: false},
        {text: "int variable_count;", correct: false}, 
        {text: "int$main;", correct: true},
    ]
},
{
    question: "All keywords in C are in ____________", 
    answers: [
        { text: "LowerCase letters", correct: true}, 
        { text: "UpperCase letters", correct: false},
        {text: "CamelCase letters", correct: false}, 
        {text: "None of the above", correct: false},
    ]
},
{
    question: "Which of the following is true for variable names in C?", 
    answers: [
        { text: "They can contain alphanumeric characters as well as special characters", correct: false}, 
        { text: "It is not an error to declare a variable to be one of the keywords(like goto, static)", correct: false},
        {text: "Variable names cannot start with a digit", correct: true}, 
        {text: "Variable can be of any length", correct: false},
    ]
},
{
    question: "Which is valid C expression?", 
    answers: [
        { text: "int my_num = 100,000;", correct: false}, 
        { text: "int my_num = 100000;", correct: true},
        {text: "int my num = 1000;", correct: false}, 
        {text: "int $my_num = 10000;", correct: false},
    ]
},
{
    question: "Which of the following cannot be a variable name in C?", 
    answers: [
        { text: "volatile", correct: true}, 
        { text: "true", correct: false},
        {text: "friend", correct: false}, 
        {text: "export", correct: false},
    ]
},
{
    question: "What is short int in C programming?",
    answers: [
        { text: "The basic data type of C", correct: false },
        { text: "Qualifier", correct: false },
        { text: "Short is the qualifier and int is the basic data type", correct: true },
        { text: "All of the mentioned", correct: false }
    ]
},
{
    question: "Which of the following declaration is not supported by C language?",
    answers: [
        { text: "String str;", correct: true },
        { text: "char *str;", correct: false },
        { text: "float str = 3e2;", correct: false },
        { text: "Both “String str;” and “float str = 3e2;”", correct: false },
    ]
},
{
    question: "Which keyword is used to prevent any changes in the variable within a C program?", 
    answers: [
        { text: "immutable", correct: false }, 
        { text: "mutable", correct: false },
        { text: "const", correct: true }, 
        { text: "volatile", correct: false },
    ]
},
{
    question: "What is the result of logical or relational expression in C?",
    answers: [
        { text: "True or False", correct: false },
        { text: "0 or 1", correct: true },
        { text: "0 if an expression is false and any positive number if an expression is true", correct: false },
        { text: "None of the mentioned", correct: false },
    ]
},
{
    question: "Which of the following typecasting is accepted by C language?",
    answers: [
        { text: "Widening conversions", correct: false },
        { text: "Narrowing conversions", correct: false },
        { text: "Widening & Narrowing conversions", correct:true },
        { text: "None of the mentioned", correct:false },
    ]
},
{
    question: "Where in C the order of precedence of operators do not exist?",
    answers: [
        { text: "Within conditional statements, if, else", correct: false },
        { text: "Within while, do-while", correct: false },
        { text: "Within a macro definition", correct: false },
        { text: "None of the mentioned", correct: true },
    ]
},
{
    question: "Which of the following is NOT possible with any 2 operators in C?",
    answers: [
        { text: "Different precedence, same associativity", correct: false },
        { text: "Different precedence, different associativity", correct: false },
        { text: "Same precedence, different associativity", correct: true },
        { text: "All of the mentioned", correct: false}
    ]
},
{
    question: "What is an example of iteration in C?",
    answers: [
        { text: "for", correct: false },
        { text: "while", correct: false },
        { text: "do-while", correct: false },
        { text: "all of the mentioned", correct: true },
    ]
},
{
    question: "Functions can return enumeration constants in C?",
    answers: [
        { text: "true", correct: true },
        { text: "false", correct: false },
        { text: "depends on the compiler", correct: false },
        { text: "depends on the standard", correct: false },
    ]
},
]
const questionElement = document.getElementById("question");
const answerButtons = document. getElementById("answer-buttons");
const nextButton = document. getElementById("next-btn");

let currentQuestionIndex = 0;
let score = 0;

function startQuiz(){
    currentQuestionIndex = 0;
    score = 0;
    nextButton. innerHTML = "Next";
    showQuestion();
}

function showQuestion(){

    resetState();
    let currentQuestion = questions[currentQuestionIndex];
    let questionNo = currentQuestionIndex + 1;
    questionElement. innerHTML = questionNo + ". " + currentQuestion.question;

    currentQuestion.answers. forEach(answer => {
        const button = document. createElement ("button");
        button. innerHTML = answer.text;
        button.classList.add ("btn");
        answerButtons.appendChild(button);
        if(answer.correct){
            button.dataset.correct = answer.correct;
        }
        button.addEventListener("click", selectAnswer);
        });
}

function resetState(){
    nextButton.style.display = "none";
    while(answerButtons.firstChild){
        answerButtons.removeChild(answerButtons.firstChild)
    }
}

function selectAnswer(e){
    const selectedbtn = e.target;
    const isCorrect = selectedbtn.dataset. correct === "true";
    if(isCorrect){
        selectedbtn.classList.add("correct");
        score++;
    }
    else{
        selectedbtn.classList.add("incorrect");
    }
    Array.from(answerButtons.children).forEach(button => {
        if(button.dataset.correct === "true"){
            button.classList.add("correct");
        }
        button.disabled = true;
    });
    nextButton.style.display = "block"
}

function showScore() {
    resetState();
    questionElement.innerHTML = `You scored ${score} out of ${questions.length}!`;
    nextButton.innerHTML = "Play Again";
    nextButton.style.display = "block";
}

 
function handleNextButton(){
    currentQuestionIndex++;
    if(currentQuestionIndex < questions.length){
        showQuestion();
    }else{
    showScore();
    }
}

nextButton.addEventListener("click", ()=>{
    if(currentQuestionIndex < questions.length){
        handleNextButton();
    }else{
        startQuiz();
    }
})
startQuiz();