BinaryToHexadecimal

using System;

class binToHexDirectly
{
    static string ToHex(string digitStr)
    {
        string output = "";

        switch (digitStr)
        {
            case "0000":
                output = "0";
                break;
            case "0001":
                output = "1";
                break;
            case "0010":
                output = "2";
                break;
            case "0011":
                output = "3";
                break;
            case "0100":
                output = "4";
                break;
            case "0101":
                output = "5";
                break;
            case "0110":
                output = "6";
                break;
            case "0111":
                output = "7";
                break;
            case "1000":
                output = "8";
                break;
            case "1001":
                output = "9";
                break;
            case "1010":
                output = "10";
                break;
            case "1011":
                output = "11";
                break;
            case "1100":
                output = "12";
                break;
            case "1101":
                output = "13";
                break;
            case "1110":
                output = "14";
                break;
            case "1111":
                output = "15";
                break;
        }

        return output;
    }
    static void Main()
    {
        Console.WriteLine("enter a Binary number to see its Hexadecimal representation:");
        string number = Console.ReadLine();
        char[] tmpChar = number.ToCharArray();// Converting to char array so that every digit is sepparated from the others.
        string[] tmpStr = new string[tmpChar.Length];//Converting to string for ease of control over every digit alone.
        string tmp = "";
        string[] output = new string[tmpStr.Length];
        string result = "";
        int j = 0;
        int m = 0;

        for (int i = 0; i < tmpChar.Length; i++)
        {
            if(j == 4)
            {
                char[] rev1 = tmp.ToCharArray();
                tmp = "";
                Array.Reverse(rev1);
                for (int k = 0; k < rev1.Length; k++)
                {
                    tmp += rev1[k];
                }
                tmpStr[m] = tmp;
                m++;
                j = 0;
                tmp = "";
            }
            tmp += tmpChar[tmpChar.Length - i - 1].ToString();
            j++;
            if (i == tmpChar.Length - 1 && j < 4)
            {
                if (j == 1)
                {
                    tmp += "000";
                }
                else if (j == 2)
                {
                    tmp += "00";
                }
                else if (j == 3)
                {
                    tmp += "0";
                }
                char[] rev = tmp.ToCharArray();
                tmp = "";
                Array.Reverse(rev);
                for (int s = 0; s < rev.Length; s++)
                {
                    tmp += rev[s];
                }
                tmpStr[m] = tmp;
                tmp = "";
            }
        }
        for (int i = 0; i < tmpStr.Length; i++)
        {
            output[i] = ToHex(tmpStr[tmpStr.Length - i - 1]);
            //Solving problem with Letters!
            switch (output[i])
            {
                case "10":
                    output[i] = "A";
                    break;
                case "11":
                    output[i] = "B";
                    break;
                case "12":
                    output[i] = "C";
                    break;
                case "13":
                    output[i] = "D";
                    break;
                case "14":
                    output[i] = "E";
                    break;
                case "15":
                    output[i] = "F";
                    break;
                default:
                    break;
            }
        }
        for (int i = 0; i < output.Length; i++)
        {
            result += output[i];
        }

        Console.WriteLine("\nTo Hexadecimal: {0}", result);
    }
}