BaseCalculator.cs

using System;
using System.Collections.Generic;
using System.Numerics;
using System.Text;

namespace BaseCalculator
{
    internal static class Program
    {
        private record Base(int BaseNum, string BaseName, string HelpFile, Func<string, NumberRecord> func);
        private record NumberRecord(string Number, int Base)
        {
            public string Binary => Number.ConvertTo(Base, 2);
            // public string Ternary => Number.ConvertTo(Base, 3);
            // public string Quaternary => Number.ConvertTo(Base, 4);
            // public string Quinary => Number.ConvertTo(Base, 5);
            // public string Senary => Number.ConvertTo(Base, 6);
            // public string Septernary => Number.ConvertTo(Base, 7);
            public string Octal => Number.ConvertTo(Base, 8);
            // public string Nonary => Number.ConvertTo(Base, 9);
            public string Decimal => Number.ConvertTo(Base, 10);
            // public string Undecimal => Number.ConvertTo(Base, 11);
            // public string Duodecimal => Number.ConvertTo(Base, 12);
            public string Hexadecimal => Number.ConvertTo(Base, 16);
            // public string Vigesimal => Number.ConvertTo(Base, 20);
            // public string Sexagesimal => Number.ConvertTo(Base, 60);
            public override string ToString()
            {
                var sb = new StringBuilder();
                sb.AppendLine($"Base  2: {Binary}");
                // sb.AppendLine($"Base  3: {Ternary}");
                // sb.AppendLine($"Base  4: {Quaternary}");
                // sb.AppendLine($"Base  5: {Quinary}");
                // sb.AppendLine($"Base  6: {Senary}");
                // sb.AppendLine($"Base  7: {Septernary}");
                sb.AppendLine($"Base  8: {Octal}");
                // sb.AppendLine($"Base  9: {Nonary}");
                sb.AppendLine($"Base 10: {Decimal}");
                // sb.AppendLine($"Base 11: {Undecimal}");
                // sb.AppendLine($"Base 12: {Duodecimal}");
                sb.AppendLine($"Base 16: {Hexadecimal}");
                //sb.AppendLine($"Base 20: {Vigesimal}");
                //sb.AppendLine($"Base 60: {Sexagesimal}");

                return sb.ToString();
            }
        }

        private static int ToInt32(this string s, int from) => Convert.ToInt32(s, from);
        private static string ConvertTo(this string s, int from, int to) => Convert.ToString(s.ToInt32(from), to);

        private static Base[] s_menu = {
            new( 2, "bin" ,"Converts from Binary.", (b) => new(b, 2)),
            new( 8, "oct" ,"Converts from Octal.", (o) =>  new(o, 8)),
            new( 10, "dec","Converts from Decimal.", (d)=> new(d, 10)),
            new( 16, "hex","Converts from Hexadecimal.", (h) => new(h, 16)),
            new( 0, "quit", "Quits the program", (q) => null)
        };

        private static void Menu()
        {
            foreach (var mi in s_menu)
            {
                Console.WriteLine($"{mi.BaseName}\t- {mi.HelpFile}\r\n\t{mi.BaseNum} can also be used.");
            }
        }

        private static void Main(string[] args)
        {
            Menu();
            while (true)
            {
                try
                {
                    Console.Write("Enter Base to convert from followed by the number: ");
                    string[] input = Console.ReadLine().Split(' ');

                    foreach (Base b in s_menu)
                    {
                        string cmd = input[0].ToLower();
                        if (cmd != b.BaseName && cmd != b.BaseNum.ToString())
                            continue;

                        NumberRecord n = b.func(input.Length > 1 ? input[1] : null);
                        if (n == null)
                        {
                            Console.WriteLine("Goodbye! :(");
                            return;
                        }
                        Console.WriteLine(n.ToString());
                    }
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.Message);
                }
            }
        }
    }
}