using System;

public class Program

{

    public static void Main()

    {

        String s = "0323323.02332.222";

        Console.WriteLine("Add comma only");

        Console.WriteLine(NurmericToCurrentCyFormat(s));

        Console.WriteLine("Add comma only with decimal places limit = 2");

        Console.WriteLine(NurmericToCurrentCyFormat(s,2));

        Console.WriteLine("Add comma only with decimal places limit = 6");

        Console.WriteLine(NurmericToCurrentCyFormat(s,6));

    }

    public static string NurmericToCurrentCyFormat(string dcString,int? maxDecimalPlaces = null){

        var splitted = dcString.Split('.');

            int beforeDot= int.TryParse(splitted[0],out int bfDot) ? bfDot : 0;

        if(splitted.Length > 1){

             string decimalPlaces = splitted[1];

             //Console.WriteLine("Has decimal places => '" + decimalPlaces + "'");

            if(maxDecimalPlaces.HasValue && decimalPlaces.Length > maxDecimalPlaces.Value){

                //Console.WriteLine("Has max decimal places => '" + maxDecimalPlaces.Value + "'");

                //Console.WriteLine("Over max decimal place => Decimal places = "+decimalPlaces.Length);

                decimalPlaces = decimalPlaces.Substring(0,maxDecimalPlaces.Value);

            }

            return string.Format("{0}.{1}",beforeDot.ToString("N0"),decimalPlaces);

        }

        else{

            return beforeDot.ToString("N0");

        }

    }

}