static void Main(string[] args)
{
AbstractHandler handler1 = new DOCHandler();
AbstractHandler handler2 = new XMLHandler();
AbstractHandler handler3 = new TXTHandler();
handler1.Create();
handler1.Open();
handler1.Change();
handler1.Save();
Console.WriteLine();
handler2.Create();
handler2.Open();
handler2.Change();
handler2.Save();
Console.WriteLine();
handler3.Create();
handler3.Open();
handler3.Change();
handler3.Save();
Console.ReadKey();
}