using System;

public class Encryption

{

    public static void Main()

    {

        Encryption XORProgram = new Encryption();   //XOR程式類別的宣告

        XORProgram.Encode("ABCDEF", "12345");       //呼叫Encode(加密)方法

        XORProgram.Decode("rtvxzw", "12345");       //呼叫Decode(解密)方法

    }

    public string Encode(string msg, string key)

    {

        char[] row = new char[msg.Length];

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

        {

            row[i] = (char)(msg[i] + key[i % key.Length]);

        }

        Console.WriteLine("Encode Message:" + new String(row));

        return new String(row);

    }

    public string Decode(string msg, string key)

    {

        char[] row = new char[msg.Length];

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

        {

            row[i] = (char)(msg[i] - key[i % key.Length]);

        }

        Console.WriteLine("Dncode Message:" + new String(row));

        return new String(row);

    }

}