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: flexcoders@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of wdsnapper Sent: Thursday, March 22, 2007 1:10 PM To: flexcoders@yahoogroups.com 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>
