using System;

​

​

//Write a program for Online Attendance.  The conditions are as follows:

//1.    User provides their name as Input and then application show message to "Welcome to their Name".

//2.    Jack, Steven and Mathew are banned for the organization. So, when any user enters Jack, Steven and 

//       Mathew as user name, the application raised an event and fire alarm as well as sends email to administration.

​

​

public class Program

{

    public static void Main()

    {

        AlertAdmin MyAlert = new AlertAdmin();

        GetUserInput GetUser = new GetUserInput();

        GetUser.alarm+=MyAlert.alarm;

        GetUser.getInput();

    }

}

​

public  class GetUserInput

{

    //public  delegate void mydelegate (object source, UserInfo e);

    //public  event mydelegate alarm;

    //  OR

    //public event EventHandler<UserInfo> alarm; 

    //OR

    public event Action<object, UserInfo> alarm;

    public  void getInput()

    {

        Console.WriteLine("Enter your name pls:");

        string DUserName = Console.ReadLine().ToString();   

        UserInfo userInfo = new UserInfo(DUserName);

        CheckValidUser(userInfo);

    }

    protected void CheckValidUser(UserInfo dUser)

    {

        string oUser=dUser.username.ToUpper();

        if (oUser=="JACK" || oUser=="STEVEN" || oUser=="MATHEW")

        {

            if (alarm!=null)

                alarm(this, dUser);

        }

        else

        {

            Console.WriteLine("Welcome {0}",oUser);

        }

    }

​

}

class AlertAdmin //subscriber

{

    public void alarm(object source, UserInfo e)

    {

        Console.WriteLine("{0} is invalid", e.username.ToUpper());

        SendEmail(e.username);

    }

    public void SendEmail(string TheName)

    {

        Console.WriteLine("Sending email to admin....intruder {0} just entered the premises", TheName.ToUpper());

    }

}

​

    // event information (holds address passed to listeners)

    public class UserInfo : EventArgs

    {

        public string username { get; set; }

        public UserInfo(string username)

        {

            this.username = username;

        }

    }

​

​