using System;                   

public class Program

{

    public static void Main()

    {

        Console.WriteLine("input : {0} \n Output : {1}", "2.12300m", GetSignificantNumberOfDecimalPlaces(2.12300m)); // returns 3

Console.WriteLine("input : {0} \n Output : {1}", "2.123m", GetSignificantNumberOfDecimalPlaces(2.123m));   // returns 3

Console.WriteLine("input : {0} \n Output : {1}", "2.103450m", GetSignificantNumberOfDecimalPlaces(2.103450m));  // returns 5

Console.WriteLine("input : {0} \n Output : {1}", "2.0m", GetSignificantNumberOfDecimalPlaces(2.0m)); // returns 0

Console.WriteLine("input : {0} \n Output : {1}", "2.00m", GetSignificantNumberOfDecimalPlaces(2.00m)); // returns 0

Console.WriteLine("input : {0} \n Output : {1}", "2m", GetSignificantNumberOfDecimalPlaces(2m)); // returns 0

​

​

    }

    static int GetSignificantNumberOfDecimalPlaces(decimal d)

{

    string inputStr = d.ToString();

    int decimalIndex = inputStr.IndexOf(".") + 1;

    if (decimalIndex == 0)

    {

        return 0;

    }

    return inputStr.Substring(decimalIndex ).TrimEnd(new[] { '0' }).Length;

​

}

​

}