Exactly right. You can google "floating point limitations" to find several very detailed articles on this issue.
Mark Shepherd Flex Builder Engineering --- In [email protected], "Gordon Smith" <[EMAIL PROTECTED]> wrote: > > This is a FOL of using types like Number in ActionScript or float/double > in Java, C, C++, etc. They can't do exact decimal fractions, because > they store values in binary and can't exactly represent a value like > 0.99. You'll either need to do rounding or compute in pennies rather > than dollars in order to avoid fractions. > > - Gordon > > ________________________________ > > From: [email protected] [mailto:[EMAIL PROTECTED] On > Behalf Of wdsnapper > Sent: Thursday, March 22, 2007 1:10 PM > To: [email protected] > Subject: [flexcoders] Flex Number addition math bug? > > > > I have an application that is showing me stange results from basic > addition. In short, I have a cart full of items that are all $0.99. > Each price is in a Number property of an object. The math is simple. > It is generating very odd results. If I start with: > > var total:Number = 0; > var price:Number = 0.99; > > then do: > > total += price; > total += price; > total += price; > > You would expect total to be equal to 2.97. I get 2.96999999... > The next time I add price I get 3.96. > > The following simple application illustrates the problem. Try it. Do > you see the same results? Am I doing something wrong or is there a > math bug? I can work around this but would REALLY like to understand > the root cause. > > <?xml version="1.0" encoding="utf-8"?> > <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml > <http://www.adobe.com/2006/mxml> " > layout="absolute" initialize="initIt()"> > <mx:Script> > <![CDATA[ > private var theNumber:Number = 0; > private var incrementAmount = 0.99; > > private function initIt() { > this.numberLbl.text = String(theNumber); > } > private function incrementIt():void { > theNumber += incrementAmount; > this.numberLbl.text = String(theNumber); > } > ]]> > </mx:Script> > <mx:Panel x="121" y="113" width="250" height="200" layout="absolute"> > <mx:Button x="125" y="44" label="Increment" click="incrementIt()"/> > <mx:Label id="numberLbl" x="43" y="44" text="Label" fontSize="12"/> > </mx:Panel> > > </mx:Application> >
