1

In a code written by me, I have used both below functions to calculate mod of displayed negative number.

fmod(-10,11)
(-10, 11)

Though the correct answer is 1. It always displays the answer -10 in c++. How I can solve it?

Improve this question
2

1 Answer 1

Reset to default
4

From cppreference.com:

double fmod (double numer, double denom);
The floating-point remainder of the division operation x/y calculated by this function is exactly the value x - n*y, where n is x/y with its fractional part truncated.
The returned value has the same sign as x and is less than y in magnitude.

In your case it is -10 - (-10)/11 * 11 = -10 - 0 * 11 = -10, which is correct for that implementation of fmod. If you need another answer, you should implement your own version, as modulo is defined in different ways for negative numbers.

Improve this answer
Sign up to request clarification or add additional context in comments.

4 Comments

cplusplus.com is not "C++ Reference", due to multiple mistakes inside it. cppreference.com is, since it, at least tries to follow C++ standard as closely, as possible.
My bad, took a look at the tab name, where it says "fmod - C++ Reference".
Due to the reasons mentioned: you should avoid linking new users to a site with potential mistakes, instead of an actual C++ reference.
usually I am reluctant to discredit the work of many with good intentions, but I can confirm, it happened just too often that I was mislead by wrong/incomplete information, till now I never had such experience on cppreference

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.