How to round to the nearest fourth

Question

I'm looking for a way to round a number to nearest number that can be divided by 4 without remainder

Give it a try, post your code, and we'll help you make it work. — Jacob Mattison, Apr 09 '13 at 18:43
Looks like your question is answered here: http://stackoverflow.com/questions/554204/where-is-round-in-c — Frecklefoot, Apr 09 '13 at 18:44

score 2 · Answer 1 · answered Apr 09 '13 at 18:55

2

num = std::round(num / 4.0) * 4.0;

answered Apr 09 '13 at 18:55

Benjamin Lindley

score 2 · Answer 2 · answered Apr 09 '13 at 18:55

2

Here is some pseudo code. Probably not the most efficient way, but...

if num mod 4 == 0 then you are good
if num mod 4 == 1 then subtract 1
if num mod 4 == 2 then you decide (subtract/add 2)
if num mod 4 == 3 then add 1

answered Apr 09 '13 at 18:55

Jake Smith

@Benjamin Lindley's answer seems to be what you are looking for as well. – Jake Smith Apr 09 '13 at 18:57
he might be using floating point numbers – relaxxx Apr 09 '13 at 18:58
1

he very well could be. That's why I wrote pseudo code. There are different ways to check for equality with different assumed data types. Good to point that out though. – Jake Smith Apr 09 '13 at 19:00

score -3 · Answer 3 · answered Apr 09 '13 at 18:43

-3

Use the following MACRO:

#define ALIGN4(len) (((len) + 3) & ~3) // round up to 4 items

answered Apr 09 '13 at 18:43

user2260087

Downvote for macro, especially in C++ code. Also for using low-level operators instead of clearly arithmetic options. – djechlin Apr 09 '13 at 18:46
1

he is looking for the nearest number, not necessary bigger one – relaxxx Apr 09 '13 at 18:53

3 Answers3