using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace P5.ConvertHexadecimalToBinary
{
    class Program
    {
        private static string[] binaryNumbers =
        {
            "0000","0001","0010","0011",
            "0100","0101","0110","0111",
            "1000","1001","1010","1011",
            "1100","1101","1110","1111",
        };
        private static string hexNumbers = "0123456789ABCDEF";
        static void Main(string[] args)
        {
            Console.Write("Enter the hex number -> ");
            string numberInHex = Console.ReadLine().ToUpper();
            Console.WriteLine("The binary representation is ->" + ConvertHexadecimalNumberToBinaryNumber(numberInHex));
        }

        private static string ConvertHexadecimalNumberToBinaryNumber(string pHexNumber)
        {
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < pHexNumber.Length; i++)
            {
                sb.Append(binaryNumbers[hexNumbers.IndexOf(pHexNumber[i])]);
            }
            return sb.ToString();
        }
    }
}