freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/iterate-through-an-array-with-a-for-loop.english.md

id, title, challengeType, videoUrl, forumTopicId

id	title	challengeType	videoUrl	forumTopicId
5675e877dbd60be8ad28edc6	Iterate Through an Array with a For Loop	1	https://scrimba.com/c/caeR3HB	18216

Description

A common task in JavaScript is to iterate through the contents of an array. One way to do that is with a for loop. This code will output each element of the array arr to the console:

var arr = [10, 9, 8, 7, 6];
for (var i = 0; i < arr.length; i++) {
   console.log(arr[i]);
}

Remember that arrays have zero-based indexing, which means the last index of the array is length - 1. Our condition for this loop is i < arr.length, which stops the loop when i is equal to length. In this case the last iteration is i === 4 i.e. when i becomes equal to arr.length and outputs 6 to the console.

Instructions

Declare and initialize a variable total to 0. Use a for loop to add the value of each element of the myArr array to total.

Tests

tests:
  - text: <code>total</code> should be declared and initialized to 0.
    testString: assert(code.match(/(var|let|const)\s*?total\s*=\s*0.*?;?/));
  - text: <code>total</code> should equal 20.
    testString: assert(total === 20);
  - text: You should use a <code>for</code> loop to iterate through <code>myArr</code>.
    testString: assert(/for\s*\(/g.test(code) && /myArr\s*\[/g.test(code));
  - text: You should not attempt to directly assign the value 20 to <code>total</code>.
    testString: assert(!code.replace(/\s/g, '').match(/total[=+-]0*[1-9]+/gm));

Challenge Seed

// Setup
var myArr = [ 2, 3, 4, 5, 6];

// Only change code below this line

After Test

(function(){if(typeof total !== 'undefined') { return "total = " + total; } else { return "total is undefined";}})()

Solution

var myArr = [ 2, 3, 4, 5, 6];
var total = 0;

for (var i = 0; i < myArr.length; i++) {
  total += myArr[i];
}