using System;

using System.Linq;

using System.Collections.Generic;

using System.Text;

public class Program

{

    public static string ToHexString(string str)

    {

        var sb = new StringBuilder();

​

        var bytes = Encoding.Unicode.GetBytes(str);

        foreach (var t in bytes)

        {

            sb.Append(t.ToString("X2"));

        }

        //var hexString = string.Join("", str.Select(c => ((int)c).ToString("X2")));

        //Console.WriteLine("hexString: " + hexString);

​

        return sb.ToString(); // returns: "48656C6C6F20776F726C64" for "Hello world"

    }

    public static string FromHexString(string hexString)

    {

        var bytes = new byte[hexString.Length / 2];

        for (var i = 0; i < bytes.Length; i++)

        {

            bytes[i] = Convert.ToByte(hexString.Substring(i * 2, 2), 16);

        }

​

        return Encoding.Unicode.GetString(bytes); // returns: "Hello world" for "48656C6C6F20776F726C64"

    }

    public static string ToHexNumber(string text)

    {

        var hexNumber = string.Empty;

        var bytes = Encoding.Default.GetBytes(text);

        var hexString = BitConverter.ToString(bytes);       

        var hexValues = hexString.Split('-');

        foreach (var hex in hexValues)

        {

            // Convert the number expressed in base-16 to an integer.

            var value = Convert.ToInt32(hex, 16);   

            //Console.WriteLine("hex: " + hex + " --> value: " + value);

            hexNumber += value;         

        }

        return hexNumber;

    }

    public static string FromHexNumber(string hexString)

    {

        var text = string.Empty;

​

        var num = uint.Parse(hexString, System.Globalization.NumberStyles.AllowHexSpecifier);

​

        var floatVals = BitConverter.GetBytes(num);

        var f = BitConverter.ToSingle(floatVals, 0);

        Console.WriteLine("float convert = {0}", f);

​

        return text;

    }

    public static void Main()

    {

        var text = "Hello world";

        var hexString = ToHexString(text);

        Console.WriteLine("text --> hex: " + hexString);

        text = FromHexString(hexString);

        Console.WriteLine("hex --> text: " + text);

        var hexNumber = ToHexNumber(text);

        Console.WriteLine("text --> hex number: " + hexNumber);

        text = FromHexNumber(hexNumber);

        Console.WriteLine("hex number --> text: " + text);

    }

}