Correct way for get fractional part double like int

Question

I need get fractional part of double like int and only two numbers. My code

(int)Math.Floor(val * 100 - (int)val * 100)

but this can (int)val * 100 may be out of range of int or long. Ok. If i try

(int)Math.Floor((val - (int)val) * 100)

Return value may be incorrect. For example:

double val = 56.9;
int retVal = (int)Math.Floor((val - (int)val) * 100);
// retVal = 89, because (val - (int)val) return 0.899999999675

How correct get fractional part of double like int?

possible duplicate of [Get the decimal part from a double](http://stackoverflow.com/questions/13038482/get-the-decimal-part-from-a-double) — Andrey Korneyev, Mar 04 '15 at 07:22
To get around rounding errors you should use `decimal` if possible. — marsze, Mar 04 '15 at 07:31
possible duplicate of [C# get digits from float variable](http://stackoverflow.com/questions/1040707/c-sharp-get-digits-from-float-variable) — Yoh Deadfall, Mar 04 '15 at 07:44
check this [https://stackoverflow.com/q/55160793/11065582](https://stackoverflow.com/q/55160793/11065582) — , Mar 14 '19 at 11:20

score 2 · Accepted Answer · answered Mar 04 '15 at 07:30

2

Try this extensions method:

public static int GetFrac2Digits(this double d)
{
    var str = d.ToString("0.00", CultureInfo.InvariantCulture);
    return int.Parse(str.Substring(str.IndexOf('.') + 1));
}

answered Mar 04 '15 at 07:30

denys-vega

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score 0 · Answer 2 · answered Mar 04 '15 at 07:22

0

try this

double val = 56.9;
double result=0;
int retVal = (int)Math.Floor((val - (int)val) * 100);
// retVal = 89, because (val - (int)val) return 0.899999999675
int FrctPart=result.ToString().Split('.')[1]

answered Mar 04 '15 at 07:22

Dgan

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marsze · Answer 3 · 2015-03-04T07:41:35.217

0

Like this maybe?

decimal d = (decimal)val;
int retVal = Math.Floor((d - Math.Floor(d)) * 100);
// 59.9 --> 90
// 123.456 --> 45

edited Mar 04 '15 at 07:41

answered Mar 04 '15 at 07:29

marsze

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The `Math.Round()` function may alter the digits. I think is not the better solution. – denys-vega Mar 04 '15 at 07:35

score 0 · Answer 4 · answered Mar 04 '15 at 08:03

0

You could also use Math.Truncate instead of casting to int:

double val = 56.9;
int retVal = (int)Math.Round((val-Math.Truncate(val)) * 100);
// retVal is now 90

answered Mar 04 '15 at 08:03

Hans Keﬆing

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Correct way for get fractional part double like int

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