using System;

class PointSet
{
	IPoint[] points; // “points” can contain references of any class implementing IPoint
	int num;

	public PointSet ( int size) 
	{
		points = new IPoint[size];
		num = 0;
	}
	public void AddPt ( IPoint p ) 
	{
		points[num++] = p;
	}

	public void PrintAll()
	{
		for(int i = 0; i < num; i++)
			points[i].PrintPt();
	}
}

class TestClass
{
	public static void Main()
	{
		PointSet s = new PointSet(5);

		s.AddPt(new Point2D());
		s.AddPt(new Point2D());
		s.AddPt(new Point3D());
		s.AddPt(new Point2D());
		s.AddPt(new Point3D());

		s.PrintAll();
	}
}