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JavaScript JavaScript Loops, Arrays and Objects Tracking Multiple Items with Arrays Build a Quiz Challenge, Part 2 Solution

Posted by Nicolas Deroin
Nicolas Deroin
6,404 Points

Any bad habits I should kick before I move forward?

So here's my code

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

let correct = 0;
let incorrect = 0;
let grading = [];
let quiz = [
  [ 'How many stripes are there on the US flag?', '13'],
  [ 'What shape has three sides?', 'TRIANGLE'],
  [ 'What is the flight speed of an unladen swallow?', 'AFRICAN OR EUROPEAN?']
]

for ( i = 0; i < quiz.length; i += 1 ) {
    let input = prompt(quiz[i][0])

    if (input.toUpperCase() === quiz[i][1]) {
        grading.push('1')} else 
        grading.push('0')

    if (input.toUpperCase() === quiz[i][1]) {
        correct += 1} else
        incorrect += 1
  }

print(`You answered ${correct} question(s) correctly, and missed ${incorrect} question(s).`)
print(`<h2>You got these questions right:</h2>`)

for ( i = 0; i < grading.length; i += 1 ) {
  if (grading[i] === '1') {
    print(`<li> ${quiz[i][0]}</li>`)
  } }

print(`<h2>You got these questions wrong:</h2>`)

for ( i = 0; i < grading.length; i += 1 ) {
  if (grading[i] === '0') {
    print(`<li> ${quiz[i][0]}</li>`)
  } }

This code works and outputs exactly as I was expecting, but I also noticed that the way I went about it rarely - if ever - matches with Dave's technique. Are there any particularly bad habits I should kick, or is my version also acceptable?

1 Answer

Steven Parker
Steven Parker
231,236 Points
Steven Parker
Steven Parker
231,236 Points

Instead of performing the same test twice, you could combine the code blocks into a single test:

  if (input.toUpperCase() === quiz[i][1]) {
    grading.push("1");
    correct += 1;
  } else {
    grading.push("0");
    incorrect += 1;
  }

And I wouldn't call it a "bad habit", but it's more "best practice" to declare things things that don't change within the program (like "quiz") by using "const" instead of "let".

Nicolas Deroin
Nicolas Deroin
6,404 Points

Groovy, thanks for the help!