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在构建会计系统时，我遇到了一个大问题。假设我开了一张发票，然后，我必须申请与负值相同金额的信用，我有时会遇到 1 美分的舍入问题。

我的问题仅与负值有关！

让我们看看这个测试特定正负值的脚本。出于调试目的，我还发送了参数expectedResult；

<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009" 
    xmlns:s="library://ns.adobe.com/flex/spark" 
    xmlns:mx="library://ns.adobe.com/flex/mx" creationComplete="creationCompleteHandler()">

    <fx:Script>
        <![CDATA[
            import mx.formatters.CurrencyFormatter;
            import mx.formatters.NumberBaseRoundType;

            private function roundDecimal(num:Number, expectedResult:Number):void
            {
                var rnd:CurrencyFormatter = new CurrencyFormatter();
                rnd.precision = 2;
                rnd.useThousandsSeparator = false;
                rnd.currencySymbol = '';

                if (num >= 0)
                    rnd.rounding = NumberBaseRoundType.NEAREST;
                else
                    rnd.rounding = NumberBaseRoundType.DOWN; // The problem is here, ALWAYS!

                var result:Number = Number(rnd.format(num));

                if (result != expectedResult)
                    trace("Error : " + result + " (Expecting " + expectedResult + ")");
                else
                    trace("OK : " + result);
            }

            protected function creationCompleteHandler():void
            {
                var num:Number;
                var expectedResult:Number;

                // Test number 1
                num = 5.653;
                expectedResult = 5.65;
                roundDecimal(num, expectedResult);
                roundDecimal(-(num), -(expectedResult));

                trace("------------");

                // Test number 2
                num = 5.655;
                expectedResult = 5.66;
                roundDecimal(num, expectedResult);
                roundDecimal(-(num), -(expectedResult));

                trace("------------");

                // Test number 3
                num = 5.657;
                expectedResult = 5.66;
                roundDecimal(num, expectedResult);
                roundDecimal(-(num), -(expectedResult));

            }
        ]]>
    </fx:Script>

</s:WindowedApplication>

当然，我尝试修改负值的舍入类型，但没有成功..

查看不同的舍入类型及其结果：

//////////// Test 1 ////////////
if (num >= 0)
    rnd.rounding = NumberBaseRoundType.NEAREST;
else
    rnd.rounding = NumberBaseRoundType.DOWN; // The problem is here, ALWAYS!

OK : 5.65
Error : -5.66 (Expecting -5.65)
------------
OK : 5.66
OK : -5.66
------------
OK : 5.66
OK : -5.66

//////////// Test 2 ////////////
if (num >= 0)
    rnd.rounding = NumberBaseRoundType.NEAREST;
else
    rnd.rounding = NumberBaseRoundType.UP;

OK : 5.65
OK : -5.65
------------
OK : 5.66
Error : -5.65 (Expecting -5.66)
------------
OK : 5.66
Error : -5.65 (Expecting -5.66)

//////////// Test 3 ////////////
if (num >= 0)
    rnd.rounding = NumberBaseRoundType.NEAREST;
else
    rnd.rounding = NumberBaseRoundType.NEAREST; // The problem is here, ALWAYS!

OK : 5.65
OK : -5.65
------------
OK : 5.66
Error : -5.65 (Expecting -5.66)
------------
OK : 5.66
OK : -5.66

我真的被困在这里，希望能得到一些帮助。非常感谢！！

4

2 回答 2

1

Check to see if it's positive or negative and assign a sign to a var (1 or -1), take the absolute value ( Math.abs(value)) and round that. Then multiply it by the sign to get the result.

That way you always get the same result and the whether it is positive or negative doesn't matter.

于 2012-11-27T16:36:31.227 回答
0

您实际上期望舍入为负值提供与您想要的正值相反的结果。一个简单的测量方法是将正值舍入向下，负值舍入向上。（或者向上表示正面，向下表示负面，也有效）。诀窍是，如果值正好在两个可能的舍入结果的中间，NEAREST 总是四舍五入，并且您希望它只舍入负数。

于 2012-11-27T16:08:47.277 回答