encrypt

using System;
using System.Collections.Generic;

namespace Encrypt
{
    class Encrypt
    {
        private static void Main(string[] args)
        {

            List<string> cryptomsg = new List<string>();

            string command = Console.ReadLine();

            while (command.ToLower() != "start")
            {
                command = Console.ReadLine();
            }

            int messages = 0;
            command = Console.ReadLine();

            while (command.ToLower() != "end")
            {
                if (command == string.Empty)
                {
                    command = Console.ReadLine();
                    continue;
                }

                messages++;

                string currentMessage = command;
                string result = string.Empty;

                for (int i = 0; i < currentMessage.Length; i++)
                {
                    char currentSymbol = currentMessage[i];

                    if (currentSymbol >= '0' && currentSymbol <= '9')
                    {
                        result = currentSymbol + result;
                        continue;
                    }

                    if (currentSymbol >= 'A')
                    {
                        if (currentSymbol <= 'M' || (currentSymbol >= 'a' && currentSymbol <= 'm'))
                        {
                            currentSymbol = (char) (currentSymbol + 13);
                        }

                        else
                        {
                            currentSymbol = (char) (currentSymbol - 13);
                        }
                    }

                    else
                    {
                        switch (currentSymbol)
                        {
                            case ' ':
                                currentSymbol = '+';
                                break;
                            case ',':
                                currentSymbol = '%';
                                break;
                            case '.':
                                currentSymbol = '&';
                                break;
                            case '?':
                                currentSymbol = '#';
                                break;
                            case '!':
                                currentSymbol = '$';
                                break;
                            case '+':
                                currentSymbol = ' ';
                                break;
                            case '%':
                                currentSymbol = ',';
                                break;
                            case '&':
                                currentSymbol = '.';
                                break;
                            case '#':
                                currentSymbol = '?';
                                break;
                            case '$':
                                currentSymbol = '!';
                                break;
                        }
                    }

                    result = currentSymbol + result;
                }

                cryptomsg.Add(result);
                command = Console.ReadLine();
            }

            if (messages == 0)
            {
                Console.WriteLine("No messages sent.");
            }

            else
            {
                Console.WriteLine("Total number of messages: {0}", messages);

                foreach (var msg in cryptomsg)
                {
                    Console.WriteLine(msg);
                }
            }
        }
    }
}