Strange sum problem

Question

Possible Duplicate:
Elegant workaround for JavaScript floating point number problem

var sum = 0;
$('[id$=percentOfTotalEditor]').each(
    function () {
        var igEditor = $find(this.id);
        var value = igEditor.get_value();
        sum += value;
    }
);

Then you'll see the magic:

sum == 1.1, value == 0.1. But after sum += value, sum == 1.2000000000000001

WTF!?

score 0 · Accepted Answer · answered Dec 14 '10 at 12:30

0

Numbers in javascript are stored as floating points - there will be some degree of imprecision - please see linked article, or search this site for floating point arithmetic for many explanations.

answered Dec 14 '10 at 12:30

Paddy

33,309
15
79
114

ok, have you any idea, how to solve this – Sergey Metlov Dec 14 '10 at 12:33
@JooLio - did you look at the linked duplicate? – Paddy Dec 14 '10 at 12:39

score 0 · Answer 2 · answered Dec 14 '10 at 12:33

Yes, this question is a duplicate as Paddy has suggested. Still, here's another Javascript library that will allow you to work with precise decimal numbers (up to a point): http://blog.brewsession.com/2008/06/28/problematic-decimal-arithmetic-in-javascript/

Strange sum problem

2 Answers2