private static void Composite()
{
var drive = new Drive("Drive");
var a = new Directory("A");
var b = new Directory("B");
var c = new Directory("C");
var d = new Directory("D");
a.Add(new File("A1"));
a.Add(new File("A2"));
b.Add(new File("B1"));
c.Add(b);
d.Add(c);
d.Add(a);
drive.Add(d);
drive.Display();
}