Phonebook

/* Write a program that receives some info from the console about people and their phone numbers.
 * You are free to choose the manner in which the data is entered; each entry should have just one name and one number (both of them strings).
 * After filling this simple phonebook, upon receiving the command "search", your program should be able to perform a search of a contact by name and print her details in format "{name} -> {number}". In case the contact isn't found, print "Contact {name} does not exist. */

namespace _07.Phonebook
{
    using System;
    using System.Collections.Generic;

    class Phonebook
    {
        static void Main(string[] args)
        {
            var phonebook = new Dictionary<string, HashSet<string>>();
            string textLine;
            FillPhonebookWithContacts(phonebook);

            List<string> contacts = new List<string>();
            textLine = Console.ReadLine().Trim();
            while (textLine != string.Empty)
            {
                contacts.Add(textLine);
                textLine = Console.ReadLine().Trim();
            }

            GetContactFromPhonebook(phonebook, contacts);
        }

        private static void FillPhonebookWithContacts(Dictionary<string, HashSet<string>> phonebook)
        {
            string textLine = Console.ReadLine().Trim();
            while (textLine != "search")
            {
                string[] entries = textLine.Split('-');
                if (entries.Length != 2)
                {
                    textLine = Console.ReadLine().Trim();
                    continue;
                }

                string key = entries[0].Trim();
                string value = entries[1].Trim();
                if (!phonebook.ContainsKey(key))
                {
                    phonebook[key] = new HashSet<string>();
                }

                phonebook[key].Add(value);
                textLine = Console.ReadLine().Trim();
            }
        }

        private static void GetContactFromPhonebook(Dictionary<string, HashSet<string>> phonebook, List<string> contacts)
        {
            foreach (string contact in contacts)
            {
                if (phonebook.ContainsKey(contact))
                {
                    Console.WriteLine("{0} -> {1}", contact, string.Join(", ", phonebook[contact]));
                }
                else
                {
                    Console.WriteLine("Contact " + contact + " does not exist.");
                }
            }
        }
    }
}