static void Main(string[] args)
{
IIndex <Rectangle> rectangle = RectangleCollection.GetRectangle();
IIndex <Shape> shape = rectangle;
for (int i = 0; i < shape.Count; i++)
{
Console.WriteLine(shape[i]);
}
IDsplay <Shape> shapeDisplay = new ShapeDisplay();
IDsplay <Rectangle> rectangleDisplay = shapeDisplay;
rectangleDisplay.Show(rectangle[0]);
}
public static RectangleCollection GetRectangle()
{
return(coll ?? (coll = new RectangleCollection()));
}