Div for float numbers c++

Asked Jan 13 '16 at 12:04

Active Aug 15 '19 at 18:29

Viewed 1,421 times

I was wondering if a function like div exists for float numbers in C++. If I need both the integral division result and the remainder, div provides that:

For example:

const auto foo = div(5, 2);
const auto quot = foo.quot; // This will be 2
const auto rem = foo.rem; // This will be 1

But this doesn't work with floats. Trying to do div(0.4, 0.8) gives the compiler error:

'div': ambiguous call to overloaded function

How can I use div for floats?

edited Aug 15 '19 at 18:29

Jonathan Mee

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asked Jan 13 '16 at 12:04

Agisilaos Vasileiadis

2

Add .0 to your number, like 5/2.0. – kometen Jan 13 '16 at 12:06
3

Please define *"it wont work"*, and provide [mcve]. – user694733 Jan 13 '16 at 12:06
"It won't work" What exactly are you expecting will happen and what happens instead? – Magisch Jan 13 '16 at 12:07
When i say it wont work i mean that, for example i want 0.4/0.8 to return 0 like the div function if it were 4/8. – Agisilaos Vasileiadis Jan 13 '16 at 12:07
You probably meant the modulo operator didn't work? – πάντα ῥεῖ Jan 13 '16 at 12:07
"it won't work" What did you try? What did you expect and what did you get? – MikeCAT Jan 13 '16 at 12:08
do you mean `floor`? isn't that in `math.h` or something? – cat Jan 13 '16 at 12:09
3

There is a [`fmod()`](http://en.cppreference.com/w/cpp/numeric/math/fmod) in the standard library. – StoryTeller - Unslander Monica Jan 13 '16 at 12:11
@PeteBecker I thought so too. Sadly that's wrong: http://stackoverflow.com/q/34767710/2642059 – Jonathan Mee Jan 13 '16 at 15:27
@JonathanMee - you're right. I've deleted my comment. – Pete Becker Jan 13 '16 at 15:32
@Bob__ You can't use `remainder`. It works like `remquo` which also doesn't work: http://stackoverflow.com/q/34767710/2642059 – Jonathan Mee Jan 13 '16 at 16:49
@JonathanMee you are right, for `std::remainder` In contrast to `std::fmod()`, the returned value is not guaranteed to have the same sign as x. – Bob__ Jan 13 '16 at 17:03
@Bob__ Your comment is very helpful without that though. So in lieu of this being reopened so you can actually answer, I'd appreciate if you could delete that comment and repost, sans `remainder`. – Jonathan Mee Jan 13 '16 at 17:06
2

You can use [`std::trunc(x/y);`](http://en.cppreference.com/w/cpp/numeric/math/trunc) for quotient and [`std::fmod(x,y);`](http://en.cppreference.com/w/cpp/numeric/math/fmod) for remainder. I don't know of any equivalent of div for floats. – Bob__ Jan 13 '16 at 17:18

Div for float numbers c++

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