using System;
using System.Collections.Generic;

namespace DeveloperTest
{
    class Program
    {
        static void Main(string[] args)
        {
            var users = new List<User>();

            users.Add(new User("John Smith", "42", DateTime.Today));

            string name = "Jane Smith";
            int age = 37;
            int yearJoined = 17;
            int monthJoined = 01;
            int dayJoined = 15;
            users.Add(new User()
            {
                Name = name,
                Age = age,
                DateJoined = new DateTime(day: dayJoined, month: monthJoined, year: yearJoined)
            });

            users[0].PrintUserInfo();

            RemoveUsersUnderAge(users, 40);

            Console.ReadKey();
        }

        private void RemoveUsersUnderAge(List<User> users, int age)
        {
            foreach (var user in users)
            {
                if (user.Age < age)
                {
                    users.Remove(user);
                }
            }
        }
    }

    class User
    {
        private string _name;
        private int _age;
        private DateTime _dateJoined;

        public User()
        {

        }

        public User(string name, string age, DateTime dateJoined)
        {
            if (name == null) Name = "Unknown";
            if (age == null) Age = 0;
            if (dateJoined == null) DateJoined = DateTime.Today;

            Name = name;
            Age = Convert.ToInt32(age);
        }

        public string Name
        {
            get { return _name; }
            set { _name = value; }
        }

        public int Age
        {
            get { return _age; }
            set { _age = value; }
        }

        public DateTime DateJoined
        {
            get { return _dateJoined; }
            set { _dateJoined = value; }
        }

        private void PrintUserInfo()
        {
            Console.WriteLine($"Name: {this.Name}.");
            Console.WriteLine($"Age: {this.Age} years old.");
            Console.WriteLine($"Joined: {this.DateJoined}.");
        }
    }
}