10.AssociativeArray-SoftUni Parking

10.SoftUni Parking
SoftUni just got a new parking lot. It’s so fancy, it even has online parking validation. Except the online service doesn’t work. It can only receive users’ data, but it doesn’t know what to do with it. Good thing you’re on the dev team and know how to fix it, right?
Write a program, which validates a parking place for an online service. Users can register to park and unregister to leave.
The program receives 2 commands:
• "register {username} {licensePlateNumber}":
o   The system only supports one car per user at the moment, so if a user tries to register another license plate, using the same username, the system should print:
"ERROR: already registered with plate number {licensePlateNumber}"
o   If the aforementioned checks passes successfully, the plate can be registered, so the system should print:
 "{username} registered {licensePlateNumber} successfully"
• "unregister {username}":
o   If the user is not present in the database, the system should print:
"ERROR: user {username} not found"
o   If the aforementioned check passes successfully, the system should print:
"{username} unregistered successfully"
After you execute all of the commands, print all the currently registered users and their license plates in the format:
• "{username} => {licensePlateNumber}"
Input
• First line: n – number of commands – integer
• Next n lines: commands in one of the two possible formats:
o   Register: "register {username} {licensePlateNumber}"
o   Unregister: "unregister {username}"
The input will always be valid and you do not need to check it explicitly.
Examples
Input                                                              Output
5
register John CS1234JS                                             John registered CS1234JS successfully
register George JAVA123S                                           George registered JAVA123S successfully
register Andy AB4142CD                                             Andy registered AB4142CD successfully
register Jesica VR1223EE                                           Jesica registered VR1223EE successfully
unregister Andy                                                    Andy unregistered successfully
                                                                   John => CS1234JS
                                                                   George => JAVA123S
                                                                   Jesica => VR1223EE


4
register Jony AA4132BB                                             Jony registered AA4132BB successfully
register Jony AA4132BB                                             ERROR: already registered with plate number AA4132BB
register Linda AA9999BB                                            Linda registered AA9999BB successfully
unregister Jony                                                    Jony unregistered successfully
                                                                   Linda => AA9999BB



6
register Jacob MM1111XX                                            Jacob registered MM1111XX successfully
register Anthony AB1111XX                                          Anthony registered AB1111XX successfully
unregister Jacob                                                   Jacob unregistered successfully
register Joshua DD1111XX                                           Joshua registered DD1111XX successfully
unregister Lily                                                    ERROR: user Lily not found
register Samantha AA9999BB                                         Samantha registered AA9999BB successfully
                                                                   Joshua => DD1111XX
                                                                   Anthony => AB1111XX
                                                                   Samantha => AA9999BB

using System;
using System.Collections.Generic;
using System.Linq;

namespace _04Orders
{
    class Program
    {
        static void Main(string[] args)
        {
            var numberCommands = int.Parse(Console.ReadLine());
            var username = new Dictionary<string, string>();

            for (int i = 1; i <= numberCommands; i++)
            {
                var command = Console.ReadLine().Split();
                if (command[0] == "register")
                {
                    if (username.ContainsKey(command[1]) == false)
                    {
                        username.Add(command[1], command[2]);
                        Console.WriteLine($"{command[1]} registered {username[command[1]]} successfully");
                    }                                                 //Или command[2]
                    else
                    {
                        Console.WriteLine($"ERROR: already registered with plate number {command[2]}");
                    }                                                                  //Или username[command[1]]
                }
                else
                {
                    if (username.ContainsKey(command[1]) == false)
                    {
                        Console.WriteLine($"ERROR: user {command[1]} not found");
                    }
                    else
                    {
                        username.Remove(command[1]);
                        Console.WriteLine($"{command[1]} unregistered successfully");
                    }
                }
            }
            foreach (var item in username)
            {
                Console.WriteLine($"{item.Key} => {item.Value}");
            }
        }
    }
}