Sierpinski Triangle Question (very quick)

[Jonny Carterson]

Hello, I am stuck at a part in this triangle creation. I need to add X from the random to X from the last point in the arrayList and add Y from the random to Y from the last point in the arrayList. I tried using "getX()" and "getY()" to try to get the coordinate from the arraylist, but I am having no luck.

I am stuck and don't know how to get the index of the last X coordinate or the Y coordinates.

So pretty much this is my trouble (as in I know how to get new random points, but how do I add these new x and y points to the last point and then divide them in half?):

for (int i = 0; i < 50; i++) {

			int x = rnd.nextInt(500);
			int y = rnd.nextInt(500);
			
		
			

			int add1 = ((x + getX()) / 2);
			int add2 = ((y + getY()) / 2);

			randomPoints.add(new Point(add1, add2));

import javax.swing.*;
import java.awt.*;
import java.util.ArrayList;
import java.util.Random;

public class ShapePanel extends JPanel {

	public final int THICKNESS = 10;
	private Point[] vertices;
	private ArrayList<Point> randomPoints;
	private Random rnd;

	public ShapePanel() {
		setBounds(0, 0, 500, 500);
		setBackground(Color.BLACK);

		vertices = new Point[3];
		vertices[0] = new Point(10, 490);
		vertices[1] = new Point(250, 10);
		vertices[2] = new Point(490, 490);

		// Get a random point anywhere on the screen.

		rnd = new Random();
		randomPoints = new ArrayList<Point>();

		// Put the points x, y into arrayList

		// Generate 50 more random points;

		for (int i = 0; i < 50; i++) {

			int x = rnd.nextInt(500);
			int y = rnd.nextInt(500);
			
		
			

			int add1 = ((x + getX()) / 2);
			int add2 = ((y + getY()) / 2);

			randomPoints.add(new Point(add1, add2));

			// grab x and y from the random index
			// grab x and y from the last point in the array list
			// average x and average y gives you the midpoint

		}

	}

	@Override
	public void paintComponent(Graphics g) {
		super.paintComponent(g);

		// Loop to draw the points in vertices
		g.setColor(Color.GREEN);
		for (Point p : vertices) {

			g.fillOval(p.x, p.y, THICKNESS, THICKNESS);

		}

		g.setColor(Color.YELLOW);
		for (Point p : randomPoints) {

			g.fillOval(p.x, p.y, THICKNESS, THICKNESS);

		}

	}

	public static void main(String[] args) {

		JFrame frame = new JFrame("Triangle!");
		frame.setDefaultCloseOperation(frame.EXIT_ON_CLOSE);
		frame.setBounds(0, 0, 550, 550);

		// Create a panel

		ShapePanel p = new ShapePanel();
		frame.add(p);

		frame.setVisible(true);

	}
}

[Ivan Jozsef Balazs]

> ArrayList<Point> randomPoints

So randomPoints is an ArrayList, an ArrayList is a List and has this method: size()

int size()
/*
Returns the number of elements in this list. If this list contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.
Returns:
    the number of elements in this list
*/

So if a List has at least one element, the last one can be obtained as

list.get ( list.size()-1);