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

luther wardle
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luther wardle
Full Stack JavaScript Techdegree Student 18,029 Points

Build a quiz challenge-using 2 dimensional arrays:

Greetings, Here is my code to build a quiz using arrays The console returns this error

Uncaught TypeError: Cannot read property '0' of undefined at quiz.js:12 I checked and for some reason, it can't read my array at [i][0];

can anyone explain my problem? here's my code:

var questions = [ ['how many apples are in a tree','7'] ['how many groundhogs are there','1'] ];

var correctAnswers = 0 var question; var response; var html;

for(i=0;i<questions.length;i++){ question = questions[i][0]; answer = questions[i][1]; response=parseInt(prompt(question)); if(response===answer){ correctAnswers+=1; } } html='you got'+correctAnswers+'questions correct'; print(html);

2 Answers

Steven Parker
Steven Parker
229,608 Points

I see two issues with the declaration of "questions":

  • there should be a comma between the two inner arrays
  • based on how the code uses them, the answers should be numbers instead of strings
var questions = [
  ["how many apples are in a tree", 7],
  ["how many groundhogs are there", 1]
];