using System;

​

public class MyProgram

{

    private static Random random = new Random();

    public static void Main(string[] args)

    {

        string[] usernames = new string[5];

        int[] passwords = new int[5];

        string user;

        int pass;

        int attempts;

        int index;

        bool access;

        for (index = 0; index <= 4; index++)

        {

            usernames[index] = Convert.ToString((char)(random.Next(25) + 65)) + (char)(random.Next(25) + 65) + (char)(random.Next(25) + 65);

        }

        for (index = 0; index <= 4; index++)

        {

            passwords[index] = random.Next(899) + 100;

        }

        output("Username, Password" + "\n");

        for (index = 0; index <= 4; index++)

        {

            output(usernames[index] + ", " + passwords[index] + "\n");

        }

        output("Enter a username:" + "\n");

        user = inputText();

        output("Enter a password:" + "\n");

        pass = (int) inputValue();

        access = false;

        attempts = 0;

        index = 0;

        while (index < usernames.Length && access == false)

        {

            if (usernames[index] == user && passwords[index] == pass)

            {

                access = true;

            }

            else

            {

                index = index + 1;

            }

        }

        while (access == false && attempts < 2)

        {

            attempts = attempts + 1;

            output("Invalid Username and Password. Please Try Again." + "\n");

            output("Enter a username:" + "\n");

            user = inputText();

            output("Enter a password:" + "\n");

            pass = (int) inputValue();

            index = 0;

            while (index < usernames.Length && access == false)

            {

                if (usernames[index] == user && passwords[index] == pass)

                {

                    access = true;

                }

                else

                {

                    index = index + 1;

                }

            }

        }

        if (access == true)

        {

            output("Welcome to the System." + "\n");

        }

        else

        {

            output("Sorry. Access Denied." + "\n");

        }

    }

    // .NET can only read single characters or entire lines from the console.

    // The following functions are designed to help input specific data types.

    private static double inputValue()

    {

        double result;

        while (!double.TryParse(Console.ReadLine(), out result));

        return result;

    }

    private static string inputText()

    {

        return Console.ReadLine();

    }

    private static void output(string text)

    {

        Console.WriteLine(text);

    }

}

​