Bingocheck

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

namespace BINGO
{
    class Program
    {
        static string user;
        static bool bingo = false;
        static string[,] table = new string[5, 5];
        static void Main(string[] args)
        {
            fillcard(table);
            Console.WriteLine("Welcome to BINGO, What is your name?");
            user = Console.ReadLine();
            Console.WriteLine("Hello " + user + ", here is your bingo card.");
            printboard(table);
            Master(table, bingo);
        }
        static string[,] Master(string[,] table, bool bingo)
        {
            Random rnd = new Random();
            while (bingo == false)
            {
                string letter = "";
                int number = 0;
                int num = rnd.Next(1, 5), B = rnd.Next(1, 15), I = rnd.Next(16, 30), N = rnd.Next(31, 45), G = rnd.Next(46, 60), O = rnd.Next(61, 75);
                switch (num)
                {
                    case 1:
                        letter = "B";
                        number = B;
                        break;
                    case 2:
                        letter = "I";
                        number = I;
                        break;
                    case 3:
                        letter = "N";
                        number = N;
                        break;
                    case 4:
                        letter = "G";
                        number = G;
                        break;
                    case 5:
                        letter = "O";
                        number = O;
                        break;
                }
                Console.WriteLine(letter + " " + number);
                var waitTime = new TimeSpan(0, 0, 1);
                var waitUntil = DateTime.Now + waitTime;

                waitUntil = DateTime.Now + waitTime;

                while (DateTime.Now <= waitUntil)
                {
                    Thread.Sleep(1000);
                    if (Console.KeyAvailable)
                    {
                        ConsoleKeyInfo k = Console.ReadKey(true);
                        Console.WriteLine("Do you have BINGO or a mark?");
                        string response = Console.ReadLine().ToLower();
                        if(response == "mark")
                        {
                            checkmark(table, number);
                            Console.Clear();
                            printboard(table);
                        }
                        else if(response == "bingo")
                        {

                        }
                    }

                }
            }
            return table;
        }
        static string[,] checkmark(string[,] table, int number)
        {
            for (int i = 0; i < 5; i++)
            {
                for (int j = 0; j < 5; j++)
                {
                    if(table[i,j] == "X ")
                    {

                    }
                    else if (number == Convert.ToInt32(table[i, j]))
                    {
                        table[i, j] = "X ";
                    }
                }
            }
            return table;
        }
        static string[,] fillcard(string[,] table)
        {
            int i, j, step = 0;
            Random rnd = new Random();
            int[] prev = new int[100];
                string letter = "";
                for (i = 0; i < 5; i++)
                {
                for (j = 0; j < 5; j++)
                {
                    int B = rnd.Next(1, 15), I = rnd.Next(16, 30), N = rnd.Next(31, 45), G = rnd.Next(46, 60), O = rnd.Next(61, 75);
                    switch (j)
                    {
                        case 0:
                            letter = Convert.ToString(B);
                            break;
                        case 1:
                            letter = Convert.ToString(I);
                            break;
                        case 2:
                            letter = Convert.ToString(N);
                            break;
                        case 3:
                            letter = Convert.ToString(G);
                            break;
                        case 4:
                            letter = Convert.ToString(O);
                            break;
                    }
                    bool next = false;
                    if(Convert.ToInt32(letter) < 10)
                    {
                        letter = (letter + " ");
                    }
                    if (!(step == 0))
                    {
                        for (int k = 0; k < prev.Length; k++)
                        {
                            if (Convert.ToInt32(letter) == prev[k])
                            {
                                if(j == 0)
                                {

                                }
                                else {
                                    j--;
                                }
                                break;
                            }
                            else
                            {
                                next = true;
                            }
                        }
                    }
                    if (next == true)
                    {
                        if (i == 2 && j == 2)
                        {
                        }
                        else
                        {
                            Console.WriteLine(j);
                            Console.WriteLine(letter);
                            Console.WriteLine();
                            table[i, j] = Convert.ToString(letter);
                        }

                    }
                    else
                    {
                        Console.WriteLine(j);
                        Console.WriteLine(letter);
                        Console.WriteLine();
                        table[i, j] = Convert.ToString(letter);
                    }
                    prev[step] = Convert.ToInt32(letter);
                    step++;
                }
            }

            return table;
        }
        static void printboard(string[,] table)
        {
            int i, j;
            string[] headings = { "B", "I", "N", "G", "O" };
            for (i = 0; i < 5; i++)
            {
                Console.Write("{0}      ", headings[i]);
            }
            Console.WriteLine();

            for (i = 0; i < 5; i++)
            {
                for (j = 0; j < 5; j++)
                {
                    if (i == 2 && j == 2)
                        Console.Write("X      ");
                    else
                        Console.Write("{0}     ", table[i, j]);
                }
                Console.WriteLine();
            }
        }
    }
}