B64 Encode

using System;
using System.Linq;
using System.Text;

namespace B64Del
{
    class Program
    {

        private static char[] arr =
        {
            'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I',
            'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R',
            'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a',
            'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
            'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's',
            't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1',
            '2', '3', '4', '5', '6', '7', '8', '9', '+',
            '/'
        };

        private static string StrToBin(string str)
        {
            string bin = "";
            foreach (char c in str)
            {
                bin += Convert.ToString((int) c, 2).PadLeft(8, '0');
            }
            return bin;
        }

        private static string BinToLet(string bin)
        {
            return arr[Convert.ToInt32(bin, 2)].ToString();
        }

        private static int DecideOverLen(int len)
        {
            if (len % 6 == 0) return len / 6;
            else return len / 6 + 1;
        }

        private static string B64Encrypt(string str)
        {
            string binaryStr = StrToBin(str);
            string[] thing = new string[DecideOverLen(binaryStr.Length)];

            // forming bin str
            for (int i = 0; i < thing.Length; i++)
            {
                for (int j = 0; j < 6; j++)
                {
                    try
                    {
                        thing[i] += binaryStr[i * 6 + j];
                    } catch {}
                }
            }

            string res = "";

            // forming b64 res

            foreach (string bin in thing)
            {
                res += BinToLet(bin + String.Join("", Enumerable.Repeat("0", 6 - bin.Length)));
            }

            // adding = as padding

            res += String.Join("", Enumerable.Repeat("=", 4 - res.Length % 4));

            return res;
        }

        private static void Main(string[] args)
        {
            Console.WriteLine(B64Encrypt("hello world"));
            Console.ReadLine();
        }
    }
}