/// <summary>
/// The entry point of the program, where the program control starts and ends.
/// </summary>
/// <param name="args">The command-line arguments.</param>
public static void Main(string[] args)
{
// Create a simple tree structure
Composite root = new Composite();
root.AddChild(new Leaf());
root.AddChild(new Leaf());
Composite composite = new Composite();
composite.AddChild(new Leaf());
composite.AddChild(new Leaf());
root.AddChild(composite);
// perform operation on entire tree
root.DoThis();
}