测试一个浮点数是整数 [英] Test if a floating point number is an integer

问题描述

此代码（C＃3）

 双D; 
如果（D ==（双）（INT）D）...; 
  

1. 有没有更好的方式来做到这一点？


2. 对于外来的原因，我想避免双投这样;有什么好的办法比这还存在着其他？ （即使它们没有那么好）

的注：的几个人指出（重要）点==往往是有问题的改编浮点。在这种情况下，我希望在0范围的值几百，他们都应该是整数（非整数的错误），所以如果这些点不应该对我来说是一个问题。

解决方案

  D == Math.Floor（D）
  

确实换句话说同样的事情

NB：希望你知道你必须要做这种事情的时候非常小心;花车/双打会很容易积累误差微乎其微，使得精确比较（像这样）失败没有明显的理由。

This code works (C# 3)

double d;
if(d == (double)(int)d) ...;

1. Is there a better way to do this?
2. For extraneous reasons I want to avoid the double cast so; what nice ways exist other than this? (even if they aren't as good)

Note: Several people pointed out the (important) point that == is often problematic regrading floating point. In this cases I expect values in the range of 0 to a few hundred and they are supposed to be integers (non ints are errors) so if those points "shouldn't" be an issue for me.

解决方案

d == Math.Floor(d)

does the same thing in other words.

NB: Hopefully you're aware that you have to be very careful when doing this kind of thing; floats/doubles will very easily accumulate miniscule errors that make exact comparisons (like this one) fail for no obvious reason.

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