Making a function that adds numbers in an array and returns their sum in javascript

Question

I'm trying to create a function that will add the numbers in an array and return their sum. For some reason it's returning 1 instead of 15 and I'm not sure why.

var myArray = [1,2,3,4,5];  
function addThemUp(myArray) {
    var arrayTotal = myArray.length; 
    var totalSum = 0;

    for(var x = 0; x <arrayTotal; x++) {
        totalSum += myArray[x];
        return(totalSum)
    }
}

addThemUp(myArray)

It's because your return is RIGHT in the for. So, it runs once, and returns. Boom. done. Move that return outside the FOR loop. — durbnpoisn, Jun 21 '16 at 19:34
var myArray = [1,2,3,4,5]; function addThemUp (myArray) { var arrayTotal = myArray.length; var totalSum = 0; for(var x = 0; x — Aaron, Jun 21 '16 at 19:34
Possible duplicate of [How to find the sum of an array of numbers](http://stackoverflow.com/questions/1230233/how-to-find-the-sum-of-an-array-of-numbers) — Phil, Jun 21 '16 at 19:36

score 4 · Answer 1 · answered Jun 21 '16 at 19:35

4

You placed the return statement inside the loop, so it will sum the first element only and then return. Instead, you should allow the loop to complete, and return the sum only after its done:

function addThemUp (myArray) {

    var arrayTotal = myArray.length; 
    var totalSum = 0;

    for(var x = 0; x < arrayTotal; x++){
        totalSum += myArray[x];
    }

    return(totalSum); // This is where the return should be
}

answered Jun 21 '16 at 19:35

Mureinik

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1

That definitely helped. That was my issue. – Aaron Jun 21 '16 at 19:48

KevBot · Answer 2 · 2016-06-22T03:48:35.423

3

In your case, you need to fix where the return of totalSum is, to be the last statement of your function (after the loop).

That being said, you may find that adding up all the numbers in an array is much cleaner and simpler to do with reduce:

function addThemUp(myArray) {
  return myArray.reduce(function(a, b) { return a + b; });
}

var myArray = [1, 2, 3, 4, 5];
console.log(addThemUp(myArray));

edited Jun 22 '16 at 03:48

answered Jun 21 '16 at 19:51

KevBot

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score 2 · Answer 3 · edited Jun 21 '16 at 19:36

2

You should return sum after for loop

var myArray = [1, 2, 3, 4, 5];

function addThemUp(myArray) {

    var arrayTotal = myArray.length;
    var totalSum = 0;

    for (var x = 0; x < arrayTotal; x++) {
        totalSum += myArray[x];
    }
    return totalSum;
}

console.log("Sum of all elements: " + addThemUp(myArray));

edited Jun 21 '16 at 19:36

Azim

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answered Jun 21 '16 at 19:34

isvforall

8,768
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Already been asked and has a much better solution: http://stackoverflow.com/a/16751601/185672 – Phil Jun 21 '16 at 19:35
1

I implemented the OP's code and changed the code to reflect your answer and it worked. – Obinna Nwakwue Jun 21 '16 at 19:36
That was the problem. I had my return in the for loop. Thanks for the help – Aaron Jun 21 '16 at 19:49

Making a function that adds numbers in an array and returns their sum in javascript

3 Answers3