C#到Lambda - 计算小数位数/第一个有效小数

using System;
using System.Linq;

class Program
{
    static void Main()
    {
        double num = 123.4567;
        int decimalPlaces = GetDecimalPlaces(num);
        Console.WriteLine("The number of decimal places is: " + decimalPlaces);
    }

    static int GetDecimalPlaces(double num)
    {
        return ((int)num).ToString().Length - 1;
    }
}

using System;
using System.Linq;

class Program
{
    static void Main()
    {
        double num = 123.4567;
        double firstValidDecimal = GetFirstValidDecimal(num);
        Console.WriteLine("The first valid decimal is: " + firstValidDecimal);
    }

    static double GetFirstValidDecimal(double num)
    {
        string numStr = num.ToString();
        int decimalIndex = numStr.IndexOf(".");
        return double.Parse(numStr.Substring(decimalIndex + 1, 1));
    }
}