Encrypted Matrix

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Problem_4
{
    class Program
    {
        static void Main(string[] args)
        {
            string msg = Console.ReadLine();
            char dir = char.Parse(Console.ReadLine());

            string number = convertToNumber(msg);
            string num = "";
            int firstDigit = Convert.ToInt32(new string(number[0], 1));
            int lastDigit = 0;
            int secondDigit = 0;
            int beforeLastDigit = 0;
            if (convertToNumber(msg).Length > 1)
            {
                lastDigit = Convert.ToInt32(new string(number[number.Length - 1], 1));
                secondDigit = Convert.ToInt32(new string(number[1], 1));
                beforeLastDigit = Convert.ToInt32(new string(number[number.Length - 2], 1));
            }

            if (firstDigit == 0 || firstDigit % 2 == 0)
            {
                firstDigit = firstDigit * firstDigit;
            }
            if (firstDigit % 2 != 0)
            {
                firstDigit = firstDigit + 0 + secondDigit;
            }
            if (lastDigit == 0 || lastDigit % 2 == 0)
            {
                lastDigit = lastDigit * lastDigit;
            }
            if (lastDigit % 2 != 0)
            {
                lastDigit = lastDigit + 0 + beforeLastDigit;
            }
            num += firstDigit;
            for (int i = 1; i < number.Length - 1; i++)
            {
                int digit = Convert.ToInt32(new string(number[i], 1));
                int beforeDigit = Convert.ToInt32(new string(number[i - 1], 1));
                int afterDigit = Convert.ToInt32(new string(number[i + 1], 1));
                if (digit == 0 || digit % 2 == 0)
                {
                    digit = digit * digit;
                }
                if (digit % 2 != 0)
                {
                    digit = digit + beforeDigit + afterDigit;
                }
                num += digit;
            }
            num += lastDigit;
            int len = num.Length;
            char[,] matrix = new char[len, len];

            int count = 0;
            for (int i = 0; i < len; i++)
            {
                for (int j = 0; j < len; j++)
                {
                    matrix[i, j] = '0';
                }
            }

            if (dir == '\\')
            {
                for (int i = 0; i < len; i++)
                {
                    for (int j = 0; j < len; j++)
                    {
                        matrix[i, count] = num[count];
                    }
                    count++;
                }
            }
            else
            {
                for (int i = len - 1; i >= 0; i--)
                {
                    for (int j = 0; j < len; j++)
                    {
                        matrix[i, count] = num[count];
                    }
                    count++;
                }
            }

            if (convertToNumber(msg).Length == 1)
            {
                Console.WriteLine(convertToNumber(msg));
            }
            else
            {
                for (int i = 0; i < len; i++)
                {
                    for (int j = 0; j < len; j++)
                    {
                        Console.Write(matrix[i, j] + " ");
                    }
                    Console.WriteLine();
                }
            }

        }

        static string convertToNumber(string msg)
        {
            string output = "";
            for (int i = 0; i < msg.Length; i++)
            {
                int last = getValue(msg[i]) % 10;
                output += last;
            }
            return output;
        }
        static int getValue(char c)
        {
            return (int)c;
        }
    }
}