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

namespace ConsoleApplication1
{
    class Person
    {
        public int id;
        public string name;
        public string email;
        public double weight;
        public int age;

        public Person(int id, string name, string email, double weight, int age)
        {
            this.id = id;
            this.name = name;
            this.email = email;
            this.weight = weight;
            this.age = age;
        }

        public override string ToString()
        {
            return this.id + "\t" + this.name + "\t" + this.email;
        }
    }

    class Program
    {
        static void Main(string[] args)
        {

            List<Person> people = new List<Person>();

            int id = -1;
            people.Add(new Person(++id, "Bob", "bob@gmail.com", 76.31, 12));
            people.Add(new Person(++id, "Lajos", "lajcsi@freemail.hu", 31, 8));
            people.Add(new Person(++id, "Tarzan", "i.tarzan@haubsburg.hu", 45.32, 18));
            people.Add(new Person(++id, "Juli", "julcsi@gmail.com", 42.234, 14));
            people.Add(new Person(++id, "Zsolt", "zsolt@freemail.hu", 92, 15));
            people.Add(new Person(++id, "Évi", "evi@gmail.com", 38, 17));
            people.Add(new Person(++id, "Másik Évi", "evi2@gmail.com", 47.63, 18));
            people.Add(new Person(++id, "Harmadik Évi", "evi.3@gmail.com", 18.1, 21));
            people.Add(new Person(++id, "Büdöske", "ciccaa@freemail.hu", 63, 25));
            people.Add(new Person(++id, "Pilács", "pilacs@freemail.hu", 65.191, 14));
            people.Add(new Person(++id, "Elek", "elek@citromail.hu", 71, 18));
            people.Add(new Person(++id, "Péló", "pelo@gmail.com", 81.58, 42));
            people.Add(new Person(++id, "Tibor", "tibi@freemail.hu", 12, 31));
            people.Add(new Person(++id, "Qulomb", "qlom@gmail.com", 54, 17));
            people.Add(new Person(++id, "Xxxxszavéér", "xxx@gmail.com", 69, 69));
            people.Add(new Person(++id, "Dénes", "denes@gmail.com", 54, 54));

            // C# Linq:

            var groupByEmail = from person in people
                               orderby person.name
                               group person by person.email.Split(new char[] {'@'})[1] into personGroup
                               select new { Email = personGroup.Key, Person = personGroup };

            foreach (var person in groupByEmail)
                Console.WriteLine(person.Email + "\t\n\t" + string.Join("\n\t", person.Person));

            Console.Read();
        }
    }
}