I have seen posts about `0.0 == -0.0` but I wasn’t...

# announcements

[goku]

I have seen posts about 0.0 == -0.0 but I wasn’t expecting to see that in a multiplication 🤔

[Marko Mitic]

that's how floats work 😄

[Marko Mitic]

float has a dedicated sign bit, so -0 is a valid option

[Burkhard]

the first bit of each float denotes plus/minus. Therefore float have both 0.0 and -0.0 but they are equal.

[Marko Mitic]

ints only have one 0, but -Int.MIN_VALUE == Int.MIN_VALUE

[Marko Mitic]

edge cases are overflow-related, there isn't a correct way to handle those so I can't take that as a negative

[Marko Mitic]

so, two's compliment was a surprisingly brilliant idea , despite the edge cases

[Dico]

It's great how Float.NaN != Float.NaN

[Dico]

It's great that (x != x) is how you identify NaN

[Dico]

This is amazing api design

[Dico]

Violating equals contract

[Dico]

Yes

[goku]

I guess sign of your 0.0 is another thing you cant choose lol

[goku]

How do you flip sign of a double or float in this case? Apparently unary minus doesn't work

[Dico]

You could do it on the raw bits

[Al Warren]

-0.0 is an IEEE standard btw.

[goku]

Yes, I’m aware of that. This isn’t the first time I saw -0.0. But in the articles I saw in the past they mostly talked about its existence and what it returns when compared to positive zero. I wasn’t expecting to see it as a result of simple multiplication like this. I did a quick research and I couldn’t find any posts related to this. I’ve seen posts about why one should use BigDecimal over double, and how it doesn’t handle precision well, but nothing related to this. And I think this is important, or I am missing something