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JavaScript JavaScript Loops, Arrays and Objects Tracking Multiple Items with Arrays Build a Quiz Challenge, Part 1 Solution

Posted by Nir Frank
Nir Frank
3,578 Points

A question about Dave's solution, and an analysis of mine

First of all, where is Dave's script getting its questions from? As far as I can tell, he initializes the questions variable, but doesn't actually fill it with an array.

Second of all, this is my solution to the quiz problem - and I see that its quite different from Dave's. Where did I go wrong? Dave's seems much simpler, as opposed to mine. How could I shorten it or otherwise improve it?

 var questionsAnswers = [
  ['What is my first name?', 'nir'],
  ['How old am I?', 25],
  ['What city do I live in?', 'new york'],
  ['What country was I born in?', 'america']
];
var numCorrect = 0;
var listRight = '<h1>You got these questions correct:</h1><ol>';
var listWrong = '<h1>You got these questions wrong:</h1><ol>';
var guess;

//Begin Quiz Loop
for (var i = 0; i < questionsAnswers.length; i++) {
  guess = prompt(questionsAnswers[i][0]);
  if (isNaN(guess)) {
    guess = guess.toLowerCase();
  } else {
    guess = parseInt(guess);
  }
  if (guess === questionsAnswers[i][1]) {
    numCorrect += 1;
    listRight += '<li>' + questionsAnswers[i][0] + '</li>'
  } else {
    listWrong += '<li>' + questionsAnswers[i][0] + '</li>'
  }
}

listRight += '</ol>';
listWrong += '</ol>';

function print(message) {
  document.write(message);
}

print('You got ' + numCorrect + ' out of ' + questionsAnswers.length + ' questions right!');

if (numCorrect > 0) {
    print(listRight);
}

if (numWrong > 0) {
    print(listWrong);
}

1 Answer

Jonathan Grieve
MOD
Jonathan Grieve
Treehouse Moderator 91,253 Points
Jonathan Grieve
Jonathan Grieve
Treehouse Moderator 91,253 Points

I haven't attempted the challenge yet as there's a problem with workspaces but as far I can tell you've nailed down everything you need to do including capturing incorrect input.

I assume your script works? Don't worry if it's different to Dave's solution. There are often many ways of solving one programming problem. :-)

Nir Frank
Nir Frank
3,578 Points

Yup, it works! Thanks for your answer. As a follow-up question (if I may), I continued watching the videos and attempted to use Dave's newer print(message); function, which utilizes document.getElementByID() and .innerHTML. What happened was, only the wrong questions got printed out.

After some googling I simply changed:

function print(message) {
  var outputDiv = document.getElementById('output');
  outputDiv.innerHTML = message;
}

to:

//code removed for brevity...
  outputDiv.innerHTML += message;
}

But I also came across appendChild(). Is there a reason Dave doesn't get into appendChild()? Is it reserved for a different course?