378956 - 0.1 * 0.1 = 0.010000000000000002

Status: RESOLVED DUPLICATE of bug 5856

(Core :: JavaScript Engine, defect)

Description

[Sam Birch]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.3) Gecko/20070309 Firefox/2.0.0.3
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.3) Gecko/20070309 Firefox/2.0.0.3

In seamonkey, 0.1 * 0.1 goes wrong by a very small amount (equals 0.010000000000000002)

Reproducible: Always

Steps to Reproduce:
1.execute javascript outputting 0.1*0.1
2.view the answer being 0.010000000000000002
3.
Actual Results:  
The answer was 0.010000000000000002

Expected Results:  
0.1 * 0.1 = .01

Default theme

Comment 1

[Jeremy Baron]

This is prolly just your common issue with any language that stores floats in binary but I'll let someone else confirm that.

Comment 2

[Jeremy Baron]

(oops, forgot to mention in the last comment that I was moving to Core::JavaScript Engine)
Sorry for the double spam.

Comment 3

[Brian Crowder]

This is not a bug in spidermonkey, just a floating-point precision issue.

Comment 4

[Bob Clary [:bc] (inactive)]

damn midairs! actually a dupe of at least bug 5856! Was hoping to get to dupe to such an old bug... :-) but invalid works too.

Comment 5

[Bill Gianopoulos [:WG9s]]

Actually the dupe would have been better.  I wold encourage the submitter to read the explanation in bug 5856.

Comment 6

[Brian Crowder]

Agreed, not a bad dupe at all, Waldemar's explanation is fantastic, dupe away if you like.

Comment 7

[Brian Crowder]

Sorry, reopening to dupe for statistical reasons.