ConvertNumberSystems/Program.cs

using System;
using System.Collections;

namespace ConvertNumberSystems
{
    class Program
    {
        static ArrayList symbols = new ArrayList();
        static long maxCommas = 5;

        static void Main(string[] args) {
            Console.Clear();

            // Initialize Symbols
            for (int i = 48; i <= 57; i++) { symbols.Add((char)i); }
            for (int i = 65; i <= 90; i++) { symbols.Add((char)i); }


            // Get Input
            Console.Write("Input your first number: ");
            string number1 = Console.ReadLine();

            Console.Write("Input the base of that number: ");
            long base1 = Convert.ToInt64(Console.ReadLine());

            Console.Write("Input your second number: ");
            string number2 = Console.ReadLine();

            Console.Write("Input the base of that number: ");
            long base2 = Convert.ToInt64(Console.ReadLine());

            Console.Write("Input the operator to use on the numbers: ");
            string inOp = Console.ReadLine();

            Console.Write("Input the base your output Number: ");
            long outputBase = Convert.ToInt64(Console.ReadLine());


            // Calculate Numbers
            double aTD1 = anyToDecimal(number1, base1);
            double aTD2 = anyToDecimal(number2, base2);

            string result = "";
            switch (inOp[0]) {
                case '+':
                    result = decimalToAny(aTD1 + aTD2, outputBase);
                    break;
                case '-':
                    result = decimalToAny(aTD1 - aTD2, outputBase);
                    break;
                case '*':
                    result = decimalToAny(aTD1 * aTD2, outputBase);
                    break;
                case '/':
                    result = decimalToAny(aTD1 / aTD2, outputBase);
                    break;
                default:
                    result = "None";
                    break;
            }

            Console.WriteLine("Your resulting number is: {0}", result);
            Console.ReadKey();
        }

        static double anyToDecimal(string number, long _base)
        {
            if (_base == 10) { return Convert.ToDouble(number); }
            if (_base > symbols.Count || _base < 2) { return 0d; }

            string removeComma = "";
            bool foundComma = false;
            long afterComma = 0;
            for (int i = 0; i < number.Length; i++)
            {
                if (afterComma == maxCommas) { break; }
                if (number[i] != ',')
                {
                    removeComma += number[i];
                    if (foundComma)
                    {
                        afterComma++;
                    }
                }
                else
                {
                    foundComma = true;
                }
            }

            double value = 0;
            string upperCase = removeComma.ToUpper();
            for (int i = 0; i < removeComma.Length; i++)
            {
                long position = removeComma.Length - i - 1 - afterComma;
                char current = upperCase[i];
                for (long j = 0; j < _base; j++)
                {
                    if (current == (char)symbols[Convert.ToInt32(j)])
                    {
                        value += j * (double)Math.Pow(_base, position);
                        break;
                    }
                }
            }
            return value;
        }

        static string decimalToAny(double number, long _base)
        {
            string b = "";
            if (_base == 10)
            {
                return b + number;
            }
            if (_base > symbols.Count || _base < 2) { return b; }
            long hP = (long)Math.Floor((double)Math.Log((double)number) / Math.Log((double)_base));
            if (hP < 0) { hP = 0; }
            double t = number;
            long index = hP;
            while ((t > (double)Math.Pow(10, -maxCommas-1)) && (index > -maxCommas-1))
            {
                if (index == -1)
                {
                    b += ",";
                }
                double p = (double)Math.Pow((double)_base, (double)index);
                double d = (double)Math.Floor((double)t / p);
                if ((double)Math.Abs(p * d) <= t)
                {
                    t -= d * p;
                    b += "" + symbols[Convert.ToInt32(d)];
                }
                else
                {
                    b += "0";
                }
                index--;
            }
            return b;
        }
    }
}