using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

                                                        Console.WriteLine(Validar("7,123.45"));

                                            Console.WriteLine(Validar("7.123,45")); 

                                                    Console.WriteLine(Validar("7,123,456"));

                                            Console.WriteLine(Validar("7.123.456"));

                                    Console.WriteLine(Validar("123.456"));

                                            Console.WriteLine(Validar("123,456"));

                                    Console.WriteLine("------------VIEJOS----------------");

                            Console.WriteLine(Validar("1300.01"));

                            Console.WriteLine(Validar("123,"));

                            Console.WriteLine(Validar("123."));

                            Console.WriteLine(Validar("123,4"));

                            Console.WriteLine(Validar("123.4"));

                            Console.WriteLine(Validar("123.45"));

                            Console.WriteLine(Validar("123,45"));

                            Console.WriteLine(Validar("1.234.56"));

                            Console.WriteLine(Validar("1,234,56"));

                            Console.WriteLine(Validar("1,234.56"));

                            Console.WriteLine(Validar("1.234,56"));

                            Console.WriteLine(Validar("1,234.5"));

                            Console.WriteLine(Validar("1.234,5"));      

                                    Console.WriteLine(Validar("1,234"));    

​

    }

    public static string Validar(string input) {

​

var regex = @"^[+-]?[0-9]{1,}(?:[0-9]*(?:[.,][0-9]{1})?|(?:,[0-9]{3})*(?:\.[0-9]{1,2})?|(?:\.[0-9]{3})*(?:,[0-9]{1,2})?)$";

var match = Regex.Match(input, regex, RegexOptions.IgnoreCase);

if (!match.Success)

{

     //"The Number must start with 4 letters and contain no numbers.",

        return "ERROR " + input + " - EN DECIMAL " + ConvertDecimalToInt(input);

} else { 

return "OK " + input + " - EN DECIMAL " + ConvertDecimalToInt(input); 

}

    }

      private static string ConvertDecimalToInt(string strDecimal)

        {

            strDecimal = strDecimal.Replace(".", ",");

​

            if (strDecimal.Contains(","))

            {

                int decimalSeparator = strDecimal.LastIndexOf(",");  //POSICION DE LA ULTIMA COMA

                int count = strDecimal.Split(',').Length - 1; 

​

                string integerPart = strDecimal.Substring(0,decimalSeparator);

                string decimalPart = strDecimal.Substring(decimalSeparator,strDecimal.Length - decimalSeparator);

                integerPart = integerPart.Replace(",","");

                decimalPart = decimalPart.Replace(",","");

                if (count > 1) {

                                    Console.WriteLine("CASO DE MILES");

                                        string finalNumber = "";

                    int cantidadDeDecimales = strDecimal.Length - decimalSeparator - 1;

                    switch (cantidadDeDecimales) {

                        case 0:

                            finalNumber =  integerPart + "00";

                        break;

                        case 1:

                            finalNumber = integerPart + decimalPart + "0";

                        break;

                        case 2:

                            finalNumber = integerPart + decimalPart;

                        break;

                        default:

                            finalNumber = integerPart + decimalPart + "00";

                        break;

                    }

                    return finalNumber;

​

                    return "NO";

                } else if (count == 1) {

                    string finalNumber = "";

                    int cantidadDeDecimales = strDecimal.Length - decimalSeparator - 1;

                    switch (cantidadDeDecimales) {

                        case 0:

                            finalNumber =  integerPart + "00";

                        break;

                        case 1:

                            finalNumber = integerPart + decimalPart + "0";

                        break;

                        case 2:

                            finalNumber = integerPart + decimalPart;

                        break;

                        default:

                            finalNumber = integerPart + decimalPart + "00";

                        break;

                    }

                    return finalNumber;

                }

                else {

​

​

​

​

                    if (decimalPart.Length == 1) {

                        return(integerPart + decimalPart + "0");

                    } else {

                        return integerPart + decimalPart;

                    }

                }

            } else {

                return(strDecimal + "00");

            }

​

        }

}