using System;
using System.Collections.Generic;
using System.Text;
using System.Text.RegularExpressions;

namespace RegularExpression
{
    class Program
    {
        static void Main(string[] args)
        {
            Validation valid = new Validation();
            bool flag = valid.IsAlphaNumeric("10A");
            Console.WriteLine(flag);
        }
    }
    //Class for the Validation
    class Validation
    {
        //Function to test for the positive integer
        public bool IsNaturalNumber(string strNumber)
        {
            Regex NotNatural = new Regex("[^0-9]");
            Regex Natural = new Regex("0*[1-9][0-9]*");
            return !NotNatural.IsMatch(strNumber) && Natural.IsMatch(strNumber);
        }
        //Function for test the natural numbes with zero
        public bool IsWholeNumber(string strNumber)
        {
            Regex whole = new Regex("[^0-9]");
            return !whole.IsMatch(strNumber);
        }
        //Function to check for a given string is a number or not
        public bool IsNumber(string strNumber)
        {
            Regex NotNumberPattern = new Regex("[^0-9]");
            Regex TwoDotPattern = new Regex("[0-9]*[.][0-9]*[.][0-9]*");
            Regex TwoMinusPattern = new Regex("[0-9]*[-][0-9]*[-][0-9]*");
            string strValidRealPattern = "^([-][.][-.]|[0-9])[0-9]*[.]*[0-9]+$";
            string validIntegerPattern = "^([-][0-9])[0-9]*$";
            Regex objNumberPattern = new Regex("(" + strValidRealPattern + ")|(" + validIntegerPattern + ")");
            return !objNumberPattern.IsMatch(strNumber) &&
              !TwoDotPattern.IsMatch(strNumber) &&
               !TwoMinusPattern.IsMatch(strNumber) &&
               objNumberPattern.IsMatch(strNumber);

        }
        //Function to check for the alphabets
        public bool IsAlpha(string strCheck)
        {
            Regex objAlphaPattern = new Regex("[^a-zA-Z]");
            return !objAlphaPattern.IsMatch(strCheck);
        }
        //Function to check for the alphanumeric
        public bool IsAlphaNumeric(string strCheck)
        {
            Regex objAlphaNumeric = new Regex("[^a-zA-Z0-9]");
            return !objAlphaNumeric.IsMatch(strCheck);
        }
    }
}