using System;

using System.Collections.Generic;

using System.Linq;

​

/*

    1. Change the format of the output so that it prints one greeting per line. Example

    Hello John

    Hello Jane

    2. Change the output so that each user's last name is also printed

    3. Define an IsValid() function in the User class. 

        It should return true if the FirstName is not null or an empty string and

        the LastName is not null or an empty string 

        else it should return false

    4. Only say "Hello" to users that are valid

    5. Perform any refactoring for better code

*/

​

public class User

{

    public string FirstName {get; private set;} //YOU MAY NOT CHANGE THIS LINE

    public string LastName {get; private set;} //YOU MAY NOT CHANGE THIS LINE

    //YOU MAY NOT CHANGE THIS CONSTRUCTOR

    public User(string firstName = "", string lastName = "")

    {

        FirstName = firstName;

        LastName = lastName;

    }

    public void SetName(string valueName, string name)

    {

        if(valueName == "FirstName")

            FirstName = name;

        else if(valueName == "LastName")

            LastName = name;

    }

    public string PrintName()

    {

        return FirstName;

    }

}

public class Program

{

    public static void Main()

    {

        var users = new List<User>() { new User()};//YOU MAY NOT CHANGE THIS LINE

        var u1 = new User();

        u1.SetName("FirstName", "Ashok");

        u1.SetName("lastName", "Kumar");

        var u2 = new User();

        u2.SetName("FirstName", "Jane");

        u2.SetName("LastName", "Smith");

        users.Add(u1);

        users.Add(u2);

        for(int i = 0; i < users.Count; i++)

        {

            Console.Write("Hello ");

            Console.Write(users[i].PrintName());

        }

    }

}