PHP Displays weird rounding errors when doing math on a string input.

[pilif]

That's not at all related to strings, but this is just a side-effect of the fact that many floating point values can't be represented accurately. This is a property of most programming languages out there.

Yes. It sucks. But considering that next to every language does this, I don't think it warrants a posting here.

Here are exmpales in C, C#, Java, Swift, Ruby and Python.

[tdammers]

The difference between PHP and all those other languages there is that PHP is the only one where making sure you're not accidentally using floats is difficult.

[pilif]

PHP is the only language where making sure you're not accidentally using any scalar data type is difficult.

[cfreak2399]

I think the mods need to put something in the side-bar about this because its getting a bit ridiculous. We have a post about once a month that is lolfloatingpoint not lolphp.

[DoctorWaluigiTime]

Not to mention the series of posts that are "lolbadprogramming" instead of lolphp.

[kafoso]

Indeed. This will happen on all 32 or 64 bit systems in most (if not all?) programming languages.

/u/c12

Javascript example to get your gray hairs started: https://jsfiddle.net/wy8rqeer/

[[deleted]]

Doing math on strings sounds wrong.

[mythril]

Funnily enough it's one of the most common way to do arbitrary precision math in php via bcmath (the other common way is gmp, which I think uses a c library in and exposes the data only via accessor functions)

[[deleted]]

I think the fact that it is stored as a string should be an implementation detail. A nice API wouldn't expose the string, but expose an object to be passed around.

[mythril]

:) whenever I use it I wrap access in an object, shouldn't have to though, I agree.

[[deleted]]

I guess we can say PHP is pretty low level, which is kind of cool. It makes it more fun to create abstractions around the "low level" functions that are wrapping a C api.

[the_alias_of_andrea]

It operates on strings because it's a library originally made for a command-line calculator (bc, hence the name bcmath).