ConvertNumberSystems

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

namespace Convert2Base
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = 255;
            // n = 0xaab;

            for (byte b = 2; b < 35; b++)
            {
                Console.WriteLine();
                Console.WriteLine("{0:D}", n);
                Console.WriteLine(Convert.ToString(n, 10));
                Console.WriteLine(Convert.ToString(n, 2));
                Console.WriteLine(Convert.ToString(n, 8));
                Console.WriteLine("{0:X}", n);
                Console.WriteLine(Convert.ToString(n, 16));

                Console.WriteLine("Base {0}:", b);
                Console.WriteLine(Convert2Base(n, b));
                Console.WriteLine(Convert2Decimal(Convert2Base(n, b), b));
            }
        }

        static string Convert2Base(int n, byte b)
        {
            if (b > 36) throw new Exception("Can not convert to base bigger than 36");
            string result = "";
            string[] s = new string[128];
            int reminder = 0;
            int i = 0;
            while (n >= b)
            {
                reminder = n % b;
                if (reminder > 9)
                {
                    s[i] = ConvertNuber2Char(reminder).ToString();
                }
                else
                {
                    s[i] = Convert.ToString(reminder);
                }

                n /= b;
                i++;
            }
            if (n > 9)
            {
                s[i] = ConvertNuber2Char(n).ToString();
            }
            else
            {
                s[i] = Convert.ToString(n);
            }

            for (; i >= 0; i--)
            {
                result += s[i];
            }
            return result;
        }

        static char ConvertNuber2Char(int n)
        {
            // ToDo use UTF-8 code to convert not a switch
            if (n > 35) throw new Exception("Can not convert number bigger than 35 to characters from some alphabet");
            char c = '#';
            switch (n)
            {
                case 10:
                    c = 'A';
                    break;
                case 11:
                    c = 'B';
                    break;
                case 12:
                    c = 'C';
                    break;
                case 13:
                    c = 'D';
                    break;
                case 14:
                    c = 'E';
                    break;
                case 15:
                    c = 'F';
                    break;


                case 16:
                    c = 'G';
                    break;
                case 17:
                    c = 'H';
                    break;
                case 18:
                    c = 'I';
                    break;
                case 19:
                    c = 'J';
                    break;
                case 20:
                    c = 'K';
                    break;
                case 21:
                    c = 'L';
                    break;
                case 22:
                    c = 'M';
                    break;
                case 23:
                    c = 'N';
                    break;
                case 24:
                    c = 'O';
                    break;
                case 25:
                    c = 'P';
                    break;
                case 26:
                    c = 'Q';
                    break;
                case 27:
                    c = 'R';
                    break;
                case 28:
                    c = 'S';
                    break;
                case 29:
                    c = 'T';
                    break;
                case 30:
                    c = 'U';
                    break;
                case 31:
                    c = 'V';
                    break;
                case 32:
                    c = 'W';
                    break;
                case 33:
                    c = 'X';
                    break;
                case 34:
                    c = 'Y';
                    break;
                case 35:
                    c = 'Z';
                    break;

                case 36:
                    c = 'Б'; // :)
                    break;
            }
            return c;
        }

        static int Convert2Decimal(string n, byte b)
        {
            int result = 0;
            int number = 0;
            for (int i = 0; i < n.Length; i++)
            {
                try
                {
                    number = int.Parse(n[i].ToString());
                }
                catch
                {
                    number = ConvertChar2Number(n[i]);
                }
                result += number  * (int)Math.Pow(b, n.Length - 1 - i);
            }
            return result;
        }

        static int ConvertChar2Number(char c)
        {
            // ToDo use UTF-8 code to convert not a switch
            // if (n > 35) throw new Exception("Can not convert number bigger than 35 to characters from some alphabet");
            int n = 0;
            c = c.ToString().ToUpper()[0]; // convert the char to uppercase
            switch (c)
            {
                case 'A':
                    n = 10;
                    break;
                case 'B':
                    n = 11;
                    break;
                case 'C':
                    n = 12;
                    break;
                case 'D':
                    n = 13;
                    break;
                case 'E':
                    n = 14;
                    break;
                case 'F':
                    n = 15;
                    break;


                case 'G':
                    n = 16;
                    break;
                case 'H':
                    n = 17;
                    break;
                case 'I':
                    n = 18;
                    break;
                case 'J':
                    n = 19;
                    break;
                case 'K':
                    n = 20;
                    break;
                case 'L':
                    n = 21;
                    break;
                case 'M':
                    n = 22;
                    break;
                case 'N':
                    n = 23;
                    break;
                case 'O':
                    n = 24;
                    break;
                case 'P':
                    n = 25;
                    break;
                case 'Q':
                    n = 26;
                    break;
                case 'R':
                    n = 27;
                    break;
                case 'S':
                    n = 28;
                    break;
                case 'T':
                    n = 29;
                    break;
                case 'U':
                    n = 30;
                    break;
                case 'V':
                    n = 31;
                    break;
                case 'W':
                    n = 32;
                    break;
                case 'X':
                    n = 33;
                    break;
                case 'Y':
                    n = 34;
                    break;
                case 'Z':
                    n = 35;
                    break;

                case 'Б':
                    n = 36; // :)
                    break;
                default:
                    throw new Exception("The char can not be converted to a number");
            }
            return n;
        }
    }
}