In C#, how do I round a float to the nearest int?
I see Math.Ceiling and Math.Round, but these returns a decimal. Do I use one of these then cast to an Int?
+6
A:
Off the top of my head:
float fl = 0.678;
int rounded_f = (int)(fl+0.5f);
fd
2009-05-25 00:10:40
Care to explain that last f (0.5f)?
Arve Systad
2009-05-25 08:09:22
0.5f is specifying that you want 0.5 of type float with a numerical suffix: http://bit.ly/apotUt
BritishDeveloper
2010-10-13 09:09:07
+9
A:
If you want to round to the nearest int:
int rounded = (int)Math.Round(precise, 0);
You can also use:
int rounded = Convert.ToInt32(precise);
Which will use Math.Round(x, 0); to round and cast for you. It looks neater but is slightly less clear IMO.
If you want to round up:
int roundedUp = (int)Math.Ceiling(precise);
Matthew Brindley
2009-05-25 00:13:59
There is ambiguity in the question. The title suggests he wants to round up, while he states he wants the nearest int. These are 2 different things.
Simucal
2009-05-25 01:01:01
He wanted to round up. Wouldn't that be (int)Math.Ceiling(precise) ?
configurator
2009-05-25 01:01:02
I'd also like to note that Math.Round uses banker's rounding. That is, a number with a non-integer part of exactly .5 would be rounded to the nearest even number. This is useful when doing aggregate sums of rounded numbers, but is usually unexpected - Math.Round(3.5) = 4, Math.Round(6.5) = 6.
configurator
2009-05-27 18:04:03
A:
Do I use one of these then cast to an Int?
Yes. There is no problem doing that. Decimals and doubles can represent integers exactly, so there will be no representation error. (You won't get a case, for instance, where Round returns 4.999... instead of 5.)
dangph
2009-05-25 00:21:55
A:
You can cast to an int provided you are sure it's in the range for an int (Int32.MinValue to Int32.MaxValue).
Joe
2009-05-25 07:01:11