如何获得-0结果浮点计算，并在C＃中的+ 0区别呢？ [英] How to get a -0 result in floating point calculations and distinguish it from +0 in C#?

问题描述

MSDN文档中提到，双击类型包括负零。然而，无论 -1.0 / double.PositiveInfinity 和 -double.Epsilon / 2 显示返回正常0（和比较等于它）。我怎样才能得到-0？

The MSDN documentation mentions that double type includes negative zero. However, both -1.0 / double.PositiveInfinity and -double.Epsilon / 2 appear to return normal 0 (and compare equal to it). How can I get -0?

推荐答案

下面是两个之间的区别，而不检查该位的实际例子。 MSDN链接这里和的这里帮助我在构建这个例子

Here is a practical example of differentiating between the two without examining the bits. MSDN links here and here assisted me in constructing this example.

static void Main(string[] args)
{
    float a = 5 / float.NegativeInfinity;
    float b = 5 / float.PositiveInfinity;
    float c = 1 / a;
    float d = 1 / b;
    Console.WriteLine(a);
    Console.WriteLine(b);
    Console.WriteLine(c);
    Console.WriteLine(d);
}

输出：

Output:

0
0
-Infinity
Infinity

请留意-0和0这两个看起来一样的比较，输出等，但如果你被他们1分，你会得到一个-Infinity或无穷大，这取决于你零有。

Take note that -0 and 0 both look the same for comparisons, output, etc. But if you divide 1 by them, you get a -Infinity or Infinity, depending on which zero you have.

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