Get number of significant digits to the right of decimal point in c# Decimal

Question

I would like a c# function with this signature:

int GetSignificantNumberOfDecimalPlaces(decimal d)

It should behave as follows when called:

    GetSignificantNumberOfDecimalPlaces(2.12300m); // returns 3
    GetSignificantNumberOfDecimalPlaces(2.123m);   // returns 3
    GetSignificantNumberOfDecimalPlaces(2.103450m);  // returns 5
    GetSignificantNumberOfDecimalPlaces(2.0m); // returns 0
    GetSignificantNumberOfDecimalPlaces(2.00m); // returns 0
    GetSignificantNumberOfDecimalPlaces(2m); // returns 0

i.e. for a given decimal, i want the number of significant decimal places to the right of the decimal point. So trailing zeros can be ignored. My fallback is to turn the decimal into a string, trim trailing zeros, and get the length this way. But is there a better way ?

NOTE: I may be using the word "significant" incorrectly here. The required return values in the example should hopefully explain what i'm after.

score 6 · Accepted Answer · edited May 23 '17 at 12:34

6

Some very good answers here Parse decimal and filter extra 0 on the right?

decimal d = -123.456700m;

decimal n = d / 1.000000000000000000000000000000m;  // -123.4567m

int[] bits = decimal.GetBits(n);

int count = bits[3] >> 16 & 255; // 4        or byte count = (byte)(bits[3] >> 16);

edited May 23 '17 at 12:34

Community

1
1

answered Feb 16 '17 at 04:34

Slai

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sujith karivelil · Answer 2 · 2022-10-06T03:59:14.973

3

I can help you to do the same with a few string operations, This may be a workaround solution for your problem, anyway consider this suggestion, and hope that it would help you

static int GetSignificantNumberOfDecimalPlaces(decimal d)
{
    string inputStr = d.ToString(CultureInfo.InvariantCulture);
    int decimalIndex = inputStr.IndexOf(".") + 1;
    if (decimalIndex == 0)
    {
        return 0;
    }
    return inputStr.Substring(decimalIndex).TrimEnd(new[] { '0' }).Length;    
}

Working Example with all the specified inputs

edited Oct 06 '22 at 03:59

answered Feb 16 '17 at 04:04

sujith karivelil

28,671
6
55
88

thanks, it does work, but i was hoping for something that didn't have to resort to converting to strings. – Moe Sisko Feb 16 '17 at 04:11
@MoeSisko: I too hope(trying) for some perfect solution than this workaround. – sujith karivelil Feb 16 '17 at 04:13
@un-lucky: You need to ensure the invarian culture is used when using "." as the decimal separator. – AxelEckenberger Aug 10 '17 at 08:17

score 0 · Answer 3 · edited Aug 18 '23 at 21:45

0

I think this was answered before: stackoverflow.com/a/13493771/4779385

decimal argument = 123.456m;
int count = BitConverter.GetBytes(decimal.GetBits(argument)[3])[2];

edited Aug 18 '23 at 21:45

HackSlash

4,944
2
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answered Feb 16 '17 at 03:50

mindOfAi

4,412
2
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there's a difference between 123.456m and 123.4560m. i.e. if the decimal i pass in has trailing zeros, the routine should ignore them. Your code works for calling with 123.456m, but not for 123.4560m, for example. – Moe Sisko Feb 16 '17 at 03:53

score -1 · Answer 4 · answered Feb 16 '17 at 08:27

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

namespace NumberofOnes

{

public class Program

{

    static void Main(string[] args)

    {

        Console.WriteLine("enter numbers");

        decimal argument = Convert.ToDecimal(Console.ReadLine());

        double count = Convert.ToDouble(decimal.Remainder(argument, 1));

        string number = count.ToString();

        int decimalCount = 0;

        if (number.Length > 1)

        {

            decimalCount = number.Length - 2;

        }

        Console.WriteLine("decimal:" + decimalCount);

        Console.ReadKey();

    }

}

}

hope this work!!

Get number of significant digits to the right of decimal point in c# Decimal

4 Answers4