checkExam.js

// The first input array is the key to the correct answers to an exam, like ["a", "a", "b", "d"]. The second one contains a student's submitted answers.

// The two arrays are not empty and are the same length. Return the score for this array of answers, giving +4 for each correct answer, -1 for each incorrect answer, and +0 for each blank answer, represented as an empty string (in C the space character is used).

// If the score < 0, return 0.

function checkExam(array1, array2) {
  let score = 0;

  for (let i = 0; i < array1.length; i++) {
    if (array2[i] === '') {
      score += 0;
    } else if (array1[i] === array2[i]) {
      score += 4;
    } else {
      score -= 1;
    }
  }

  return score < 0 ? 0 : score;
}