Visual Studio将1.1扩展到1.100000000000000001 [英] Visual Studio expanding 1.1 to 1.1000000000000001

问题描述

至少对我来说，这是最有趣的Visual Studio 2010行为。我正在开发MVC3项目，我从另外一个项目中复制了一行代码（VS2010也是MVC1），看起来像这样：

  target_height = height * 1.1 
  

当我将它粘贴到MVC3项目中时，到

  target_height = height * 1.1000000000000001 
  

现在，如果我输入1.2，没关系，没有任何反应，但是如果输入1.12，它会扩展到1.1200000000000001。

$ b target_height高度是整数。为什么一个Visual Studio显示1.1而其他扩展到1.1000000000000001？

发生了什么???

解决方案

我认为这是自动完成疯了，并开始修正浮动点常量到允许值。正如 http://accessmvp.com/Strive4Peace/VBA/VBA_L1_02_Crystal.pdf 中所写， VB自动完成实际上只是试图提供专门适用于这种数据类型的东西。 int * double可以理解为不会被截断为int * int（自动转换总是只发生在需要的时候），你看到的是1.1或1.12（epsilon = 1.11e-16）的双重表示。

我认为在发生这种情况时，仍然需要进一步的检查或验证来学习确切的条件，但是因为我没有使用VB.NET或MVCx，所以我不愿意这么做。 em>

This is, at least for me, most bizzare Visual Studio 2010 behaviour ever. I'm working on MVC3 project, I copied a line of code from another project (VS2010 also, MVC1 if it matters) which looks like this:

target_height = height * 1.1

when I paste it into MVC3 project, it gets expanded to

target_height = height * 1.1000000000000001

Now, if I type 1.2, it's fine, nothing happens, but if I type 1.12 it is expanded to 1.1200000000000001.

Both target_height and height are integers. Why does one Visual Studio display 1.1 while other expands it to 1.1000000000000001?

What is going on???

解决方案

I think it is autocomplete went crazy and started fixing floating points constant into "allowed" values. As written in http://accessmvp.com/Strive4Peace/VBA/VBA_L1_02_Crystal.pdf , VB autocomplete really tries to offer only "things that apply specifically to that data type". int * double is understandably not truncated into int * int (automatic conversions always happen only as needed) and what you see is double representation of 1.1 or 1.12 (epsilon = 1.11e-16).

I think it would still need some further checking or verification to learn exact conditions when this happens, but as I am not using VB.NET or MVCx this is not something I am willing to do.

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