你如何生成在C＃中的随机数？ [英] How do you generate a random number in C#?

问题描述

我想生成两个值之间的随机浮点数。什么是C＃做到这一点的最好方法是什么？

I would like to generate a random floating point number between 2 values. What is the best way to do this in C#?

推荐答案

我想加入的的埃里克响应的说明;我觉得为什么代码工作，知识比知道什么代码工作更好

The only thing I'd add to Eric's response is an explanation; I feel that knowledge of why code works is better than knowing what code works.

的解释是这样的：假设你想在2.5和4.5之间的数字。的范围是2.0（4.5 - 2.5）。 NextDouble 只返回一个0到1.0之间的数字，但如果你的范围内乘这个，你会得到0和范围的之间的一个数字。

The explanation is this: let's say you want a number between 2.5 and 4.5. The range is 2.0 (4.5 - 2.5). NextDouble only returns a number between 0 and 1.0, but if you multiply this by the range you will get a number between 0 and range.

那么，这会给我们随机双打0.0到2.0之间：

So, this would give us random doubles between 0.0 and 2.0:

rng.NextDouble() * 2.0

不过，我们希望他们在2.5和4.5之间！我们如何做到这一点？添加的最小数字，2.5：

But, we want them between 2.5 and 4.5! How do we do this? Add the smallest number, 2.5:

2.5 + rng.NextDouble() * 2.0

现在，我们得到了0.0和2.0之间的数字;如果添加2.5到每一个值，我们看到现在的范围是2.5到4.5之间。

Now, we get a number between 0.0 and 2.0; if you add 2.5 to each of these values we see that the range is now between 2.5 and 4.5.

起初我以为这要紧，如果B> A或A> b，但是如果你工作了两种方式，你会发现它的作品了相同的，只要你不乱时使用的变量的顺序。我想用较长的变量名称来表达它，所以我没有得到混合起来：

At first I thought that it mattered if b > a or a > b, but if you work it out both ways you'll find it works out identically so long as you don't mess up the order of the variables used. I like to express it with longer variable names so I don't get mixed up:

double NextDouble(Random rng, double min, double max)
{
    return min + (rng.NextDouble() * (max - min));
}

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