在.NET 4 Math.Round（）行为 [英] Math.Round() behaviour in .NET 4

问题描述

  

可能显示的文件：
  <一href="http://stackoverflow.com/questions/977796/in-c-math-round2-5-result-is-2-instead-of-3-are-you-kidding-me">In C＃：Math.Round（2.5）结果是2（而不是3）！你在开玩笑吧？
  净回合错误

我有一个中间值（number.5），我需要指定如何将被舍（上限或下限值。）

我理解 Math.Round 与 MidPointRounding 参数的行为，但是这并没有解决我的问题：

  //连
Console.WriteLine（Math.Round（4.4））; // 4
Console.WriteLine（Math.Round（4.5））; // 4
Console.WriteLine（Math.Round（4.6））; // 5
Console.WriteLine（Math.Round（5.5））; // 6

// AwayFromZero
Console.WriteLine（Math.Round（4.4））; // 4
Console.WriteLine（Math.Round（4.5））; // 5
Console.WriteLine（Math.Round（4.6））; // 5
Console.WriteLine（Math.Round（5.5））; // 6

//在一种情况下，我需要
Console.WriteLine（Math.Round（4.4））; // 4
Console.WriteLine（Math.Round（4.5））; // 4
Console.WriteLine（Math.Round（4.6））; // 5
Console.WriteLine（Math.Round（5.5））; // 5

//我需要另一种情况
Console.WriteLine（Math.Round（4.4））; // 4
Console.WriteLine（Math.Round（4.5））; // 5
Console.WriteLine（Math.Round（4.6））; // 5
Console.WriteLine（Math.Round（5.5））; // 6
 

解决方案

您有过载 Math.Round 是采取从 A枚举值MidpointRounding 。

这有两个选项：

• ToEven（默认）也被称为银行家四舍五入。将舍入到最接近一对。因此，2.5变为2，而3.5变成4。
• AwayFromZero：始终轮X.5高达X + 1;因此，2.5例如变成3。

Possible Duplicates:
In C#: Math.Round(2.5) result is 2 (instead of 3)! Are you kidding me?
.Net Round Bug

I have a halfway value (number.5) and I need to specify how this will be rounded (upper or lower value.)

I understand the behaviour of Math.Round with the MidPointRounding parameter but that does not solve my problem:

// To Even
Console.WriteLine(Math.Round(4.4)); // 4
Console.WriteLine(Math.Round(4.5)); // 4
Console.WriteLine(Math.Round(4.6)); // 5
Console.WriteLine(Math.Round(5.5)); // 6

// AwayFromZero
Console.WriteLine(Math.Round(4.4)); // 4
Console.WriteLine(Math.Round(4.5)); // 5
Console.WriteLine(Math.Round(4.6)); // 5
Console.WriteLine(Math.Round(5.5)); // 6

// in one case I need 
Console.WriteLine(Math.Round(4.4)); // 4
Console.WriteLine(Math.Round(4.5)); // 4
Console.WriteLine(Math.Round(4.6)); // 5
Console.WriteLine(Math.Round(5.5)); // 5

// another case I need
Console.WriteLine(Math.Round(4.4)); // 4
Console.WriteLine(Math.Round(4.5)); // 5
Console.WriteLine(Math.Round(4.6)); // 5
Console.WriteLine(Math.Round(5.5)); // 6

解决方案

You have a overload to Math.Round that take a enum value from MidpointRounding.

This has two options:

• ToEven (default) Also called bankers rounding. Will round to the nearest pair. So 2.5 becomes 2, while 3.5 becomes 4.
• AwayFromZero: Always round X.5 up to X+1; So 2.5 for example becomes 3.

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