this post was submitted on 09 Oct 2025
774 points (99.1% liked)

Programmer Humor

28388 readers
1214 users here now

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

founded 2 years ago
MODERATORS
 
all 45 comments
sorted by: hot top controversial new old
[–] gravitas_deficiency@sh.itjust.works 49 points 3 months ago* (last edited 3 months ago) (5 children)

Look at what they need to mimic a fraction inaccurately.

The fundamental mathematical nature of how binary floating point values are stored means that extremely straightforward and rational (in the mathematical sense of the term) base-10 arithmetic can surprisingly often yield results that are irrational (again, mathematically) in binary - hence why you’ll sometimes see a result of 3.000000000101325 or something like that in places where you’d expect the result to be simply 3.0

[–] jjjalljs@ttrpg.network 27 points 3 months ago (1 children)

Yep. Open your browser's console and do .1 + .2 and you get 0.30000000000000004.

One of the reasons not to use floating point when working with money.

[–] bamboo@lemmy.blahaj.zone 12 points 3 months ago (4 children)

What's the right way to do money math without floats?

[–] orhtej2@eviltoast.org 37 points 3 months ago (2 children)
[–] felbane@lemmy.world 14 points 3 months ago

Also known as "if you ain't storing cents, you ain't making sense."

[–] KoalaUnknown@lemmy.world 11 points 3 months ago* (last edited 3 months ago) (1 children)

There is also Decimal floating-point arithmetic which has a larger range and better memory safety. Java, C#, Python, Ruby, etc. have built in support for it via Decimal.

[–] Cevilia@lemmy.blahaj.zone 4 points 3 months ago

Banks and big companies have to worry about round-off and fractions of a penny, so Decimal is a better solution for them. But the great unwashed like you and me will never have to worry about that, so either works.

[–] SmoothLiquidation@lemmy.world 12 points 3 months ago

As other people mentioned, things like the decimal structure works well, but you can also just use an int to store how many pennies something costs and convert it to dollars for display.

[–] jjjalljs@ttrpg.network 10 points 3 months ago

Use a dedicated data type or library. Some languages also have something like python's Decimal type

>>> .1 + .2
0.30000000000000004
>>> Decimal(".1") + Decimal(".2")
Decimal('0.3')
[–] JakenVeina@midwest.social 6 points 3 months ago* (last edited 3 months ago)

The same IEEE spec that introduced base-2 floating point models was updated in 2008 to include some base-10 models that eliminate these issues. Many languages already support them natively, as well as most database engines. Otherwise, you can probably find third-party-library support.

If you don't have access to an IEEE decimal implementation, or if you just wanna be a rulebreaker, the common strategy is to just store only plain integers, and the precision level you want. So, say, if you're just dealing with simple american dollars, you'd just make sure to always interpret the integer value as "cents". If you need more precision than that, you might do "millicents".

[–] CanadaPlus@lemmy.sdf.org 7 points 3 months ago* (last edited 3 months ago)

It'd be more correct to say round or unround.

Irrational specifically means infinite non-repeating decimal values, or equivalently that a number can't be represented as any fraction. This is independent of number system.

Sometimes "more irrational" is used as a way of saying further from any small-integer fraction by some measure, but that doesn't really work here.

[–] juliebean@lemmy.zip 5 points 3 months ago

i see what you're trying to say, but that's not what rational and irrational means (mathematically).

[–] 5765313496@lemmy.world 1 points 3 months ago

Look what they need to mimic a fraction of a fraction.

[–] Grandwolf319@sh.itjust.works 16 points 3 months ago* (last edited 3 months ago) (1 children)

Cause fractions can be figured out in context. You can store the numerators and have the denominator as a constant in the code.

[–] frezik@lemmy.blahaj.zone 11 points 3 months ago (2 children)

You can also have a type which does it. Raku has a Rational type for this.

[–] dontsayaword@piefed.social 5 points 3 months ago

Part of my first programming courses in the 90s in C were creating a native fraction type.

[–] Kacarott@aussie.zone 4 points 3 months ago

Python has the Fraction type, and there are many more

[–] SpaceNoodle@lemmy.world 13 points 3 months ago (1 children)
[–] orhtej2@eviltoast.org 29 points 3 months ago (2 children)
[–] wheezy@lemmy.ml 4 points 3 months ago* (last edited 3 months ago)

You like math jokes and guys with fast cars? Well, you're in luck because I drive a bmw √-64

Edit: I know nothing about cars. Don't judge me.

[–] Ephera@lemmy.ml 3 points 3 months ago

I do enjoy how many number sets are referred to as "normal numbers":

[–] hexagonwin@lemmy.sdf.org 8 points 3 months ago (1 children)

unrelated but the image shows so low res (86x96) that it's unreadable, is this different for everyone else?

what mine shows - https://eviltoast.org/pictrs/image/44915c44-8836-4961-bd06-a45bba04408a.jpeg

[–] orhtej2@eviltoast.org 9 points 3 months ago (1 children)

The link you gave shows hires for me. Can you try loading in incognito?

just pict-rs things I guess 🤷

[–] hexagonwin@lemmy.sdf.org 5 points 3 months ago (1 children)

hmm very weird. i also tried wget and it grabs the same 86x96 file. https://termbin.com/gvg9

[–] wheezy@lemmy.ml 1 points 3 months ago* (last edited 3 months ago) (1 children)

Weird. My wget gives full resolution. No redirect options or anything. Only difference is the IP resolve for you is in Korea and mine is in the US. Likely just closest server resolve.

Try curl with -L set?

Or I'd be curious if something like gallery-dl resolves the image in finding the higher resolution and what the difference is if it does.

Maybe it's a DNS issue if not a redirect issue.

My guess is DNS. Try with another provider?

[–] hexagonwin@lemmy.sdf.org 2 points 3 months ago (1 children)

You're right! 1.1.1.1 (Cloudflare) or my ISP's DNS seems to be weird. Works correctly with 9.9.9.9 (Quad9).

[–] wheezy@lemmy.ml 1 points 3 months ago
[–] deaf_fish@midwest.social 7 points 3 months ago

I think you could argue that they're actually trying to mimic real numbers.

[–] irelephant@lemmy.dbzer0.com 4 points 3 months ago

Eviltoasts pict-rs is being silly again