双精度C ++ [英] double precision C++

问题描述

我认为double的精度导致了这个问题，就像在相似的帖子中描述的那样，但是我想知道是否有办法达到正确的结果。我使用的函数模板比​​较两个参数，如果它们相等，则返回true。

  template< class T> 
 bool eq（T one，T two）
 {
 if（one == two）
 return true; 
 else 
返回false; 
 
 
 
 $ b $ p $它可以和eq（0.8,0.8）一起使用，但是不起作用与eq（0.8 * 0.2,0.16）。正如我所提到的，我认为它必须做双精度，因为它也适用于int eq（8 * 2,16）。
解决方案
首先，您应该阅读以下文章中的一篇（或两篇）：每台计算机科学家应该知道浮点运算和浮点运算的危险。 p> 
 
 
如果您正在寻找您的模板的解决方案，我会建议使用 T == double 和 T == float  template specialization  c>。
 
I think the precision of double is causing that problem, as it was described in similiar posts, but I would like to know if there is a way to achieve correct result. I'm using function template which compares two parameters and returns true if they are equal.
template <class T>
bool eq(T one, T two)
{
  if (one == two)
    return true;
  else
    return false;
}
It works with eq (0.8,0.8), but it doesn't work with eq (0.8*0.2,0.16). As I mentioned I assume it has to do with double precision as it also works fine with int eq(8*2,16).
解决方案
First you should read one (or both) of these articles: What Every Computer Scientist Should Know About Floating-Point Arithmetic and The Perils of Floating Point.

If you are looking for a solution for your template, I would suggest using template specialization for the cases where T==double and T==float.

                        
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