using System;

​

public class Program

{

    private static string Encrypt(string s)

    {

        char[] temp = s.ToCharArray();

        for (int i = 0; i < s.Length; i++)

        {

            if (temp[i] == 'A')

                temp[i] = 'M';

            else if (temp[i] == 'B')

                temp[i] = 'E';

            else if (temp[i] == 'C')

                temp[i] = 'W';

            else if (temp[i] == 'D')

                temp[i] = 'S';

            else if (temp[i] == 'E')

                temp[i] = 'A';

            else if (temp[i] == 'F')

                temp[i] = 'D';

            else if (temp[i] == 'G')

                temp[i] = 'R';

            else if (temp[i] == 'H')

                temp[i] = 'L';

            else if (temp[i] == 'I')

                temp[i] = 'I';

            else if (temp[i] == 'J')

                temp[i] = 'G';

            else if (temp[i] == 'K')

                temp[i] = 'Y';

            else if (temp[i] == 'L')

                temp[i] = 'H';

            else if (temp[i] == 'M')

                temp[i] = 'U';

            else if (temp[i] == 'N')

                temp[i] = 'J';

            else if (temp[i] == 'O')

                temp[i] = 'F';

            else if (temp[i] == 'P')

                temp[i] = 'K';

            else if (temp[i] == 'Q')

                temp[i] = 'O';

            else if (temp[i] == 'R')

                temp[i] = 'L';

            else if (temp[i] == 'S')

                temp[i] = 'P';

            else if (temp[i] == 'T')

                temp[i] = 'Z';

            else if (temp[i] == 'U')

                temp[i] = 'X';

            else if (temp[i] == 'V')

                temp[i] = 'C';

            else if (temp[i] == 'W')

                temp[i] = 'V';

            else if (temp[i] == 'X')

                temp[i] = 'B';

            else if (temp[i] == 'Y')

                temp[i] = 'N';

            else if (temp[i] == 'Z')

                temp[i] = 'M';

            else if (temp[i] == '.')

                temp[i] = '?';

            else if (temp[i] == '"')

                temp[i] = ':';

            else if (temp[i] == '0')

                temp[i] = '[';

            else if (temp[i] == '1')

                temp[i] = ']';

            else if (temp[i] == '+')

                temp[i] = '-';

        }//M E W S A D R L I G Y H U J F K O L P  Z X C V B N m

​

        string cipher = new string (temp);

        return cipher;

    }

​

    private static string Decrypt(string s)

    {

        char[] temp = s.ToCharArray();

        for (int i = 0; i < s.Length; i++)

        {

            if (temp[i] == 'M')

                temp[i] = 'A';

            else if (temp[i] == 'E')

                temp[i] = 'B';

            else if (temp[i] == 'W')

                temp[i] = 'C';

            else if (temp[i] == 'S')

                temp[i] = 'D';

            else if (temp[i] == 'A')

                temp[i] = 'E';

            else if (temp[i] == 'D')

                temp[i] = 'F';

            else if (temp[i] == 'R')

                temp[i] = 'G';

            else if (temp[i] == 'L')

                temp[i] = 'H';

            else if (temp[i] == 'I')

                temp[i] = 'I';

            else if (temp[i] == 'G')

                temp[i] = 'J';

            else if (temp[i] == 'Y')

                temp[i] = 'K';

            else if (temp[i] == 'H')

                temp[i] = 'L';

            else if (temp[i] == 'U')

                temp[i] = 'M';

            else if (temp[i] == 'J')

                temp[i] = 'N';

            else if (temp[i] == 'F')

                temp[i] = 'O';

            else if (temp[i] == 'K')

                temp[i] = 'P';

            else if (temp[i] == 'O')

                temp[i] = 'Q';

            else if (temp[i] == 'L')

                temp[i] = 'R';

            else if (temp[i] == 'P')

                temp[i] = 'S';

            else if (temp[i] == 'Z')

                temp[i] = 'T';

            else if (temp[i] == 'X')

                temp[i] = 'U';

            else if (temp[i] == 'C')

                temp[i] = 'V';

            else if (temp[i] == 'V')

                temp[i] = 'W';

            else if (temp[i] == 'B')

                temp[i] = 'X';

            else if (temp[i] == 'N')

                temp[i] = 'Y';

            else if (temp[i] == 'M')

                temp[i] = 'Z';

            else if (temp[i] == '?')

                temp[i] = '.';

            else if (temp[i] == ';')

                temp[i] = '"';

            else if (temp[i] == '[')

                temp[i] = '0';

            else if (temp[i] == ']')

                temp[i] = '1';

            else if (temp[i] == '-')

                temp[i] = '+';

        }

​

        string plain = new string (temp);

        return plain;

    }

​

    public static void Main()

    {

        Start:

        Console.WriteLine("Press 1 to Encrypt a message and 2 to Decrypt a message");

        redo:

            byte choice = byte.Parse(Console.ReadLine());

        if (choice == 1)

        {

            Console.WriteLine("Please enter your plaintext to encrypt.");

            string pt = Console.ReadLine();

            string ept = pt.ToUpper();

            Console.WriteLine("Your encrypted message is: " + Encrypt(ept));

        }

        else if (choice == 2)

        {

            Console.WriteLine("Please enter your ciphertext to decrypt.");

            string ct = Console.ReadLine();

            string dct = ct.ToUpper();

            Console.WriteLine("Your decrypted message is: " + Decrypt(dct));

        }

        else

        {

            Console.WriteLine("Please enter 1 or 2");

            goto redo;

        }

        Console.WriteLine("Would you like to redo this program Type q for no and anything else to contuine");

        string restart = Console.ReadLine();

        if(restart =="q"||restart =="Q")

        {

            Console.WriteLine("Ok bye");

        }

        else{

            Console.Clear();

            goto Start;

    }

}}