[worik]

Sigh

The representation means that 2.9999999999 = 3.00000000

I am not confused. You cannot use equality in floating point. Why is anybody surprised by that? That is my point

(I did say floating point before when I ment real. A bit confused!)

[caf]

Don't sigh melodramatically at me.

I wasn't saying you were confused, I was saying I believe I understand how the general confusion around the whole issue arises.

(If decimal floating point had been commonly used instead of binary, the same class of issues would still exist, but I don't think people would be nearly so surprised by them).

[slavik81]

> You cannot use equality in floating point.

Sure you can. 1.0 + 2.0 == 3.0. There's a lot of gotchas, but it is possible to make useful comparisons.

[worik]

No it does not, no it is not possible to use equality comparisons usefully in FP arithmetic

[slavik81]

If that were true, they wouldn't have defined the equality operators for floating point types. Some numbers are exactly representable and some numbers are not [1]. It's difficult, but you can in fact reason about the exact results of floating point calculations. https://news.ycombinator.com/item?id=1847462