static void Main(string[] args)
{
// root composite
var box = new Composite("Box", 0);
// pen and pencil in composite pencil_case
var pen = new Leaf("pen", 5);
var pencil = new Leaf("pencil", 3);
var Pencil_case = new Composite("Pencil case", 0);
var Ball = new Leaf("Ball", 200);
Pencil_case.AddChild(pen);
Pencil_case.AddChild(pencil);
// add pencil composite as child to the root composite
box.AddChild(Pencil_case);
// add leaf component as child to the root composite
box.AddChild(Ball);
Console.WriteLine($"Total price of this box is: {box.Caclulate()}");
}
