public static void Run()
{
Subject RedMI = new Subject("Red MI Mobile", 10000, "Out Of Stock");
Observer user1 = new Observer("John", RedMI);
Observer user2 = new Observer("Doe", RedMI);
Observer user3 = new Observer("Joanna", RedMI);
Console.WriteLine("Red MI Mobile current state : " + RedMI.GetAvailability());
Console.WriteLine();
RedMI.SetAvailability("Available");
Console.Read();
}