Also 1-1 ≠ 0
Are you sure? I've never seen that inequality before.
Edit: and at least python agrees with me
print(0.1 + 0.2) # 0.300...0004
print(1.0-1.0) # 0.0
I think it's equal zero in this case. I'd have to look up the IEEE specification to make sure. AFAIK it's just not guaranteed for any numbers and depends on the floating point implementation. A general rule of thumb for programmers is not to use 'equal' with floating point numbers.
The example is wrong, because they used 1.0
.
But in general x-x
does not have to equal 0
, that is true. I'm pretty sure Nan
and infinity
would yield not 0.0
, but Nan
instead.
And if you reach x with two different calculations, e.g. x1 = a - b - c
and x2 = a - c - b
it is certainly not guaranteed that x1 - x2 == 0.0
This is correct. Additionally, if x is NaN, then x ≠ x.
It does. x-x == 0
is true unless x
is NaN or infinity.
Positive or negative zero?
Programmer Humor
Welcome to Programmer Humor!
This is a place where you can post jokes, memes, humor, etc. related to programming!
For sharing awful code theres also Programming Horror.
Rules
- Keep content in english
- No advertisements
- Posts must be related to programming or programmer topics