import java.awt.*;
import javax.swing.*;

public class Parabola extends JPanel {
	public Parabola() {
		setPreferredSize(new Dimension(200, 200));;
	}
	
	@Override
	public void paintComponent(Graphics g) {
		super.paintComponent(g);
		double a = -0.0025, b = 1, c = 0;
		for (int x0 = 0; x0 < 200; x0 += 10) {
			double y0 = a * x0 * x0 + b * x0 + c;
			int x1 = x0 + 10;
			double y1 = a * x1 * x1 + b * x1 + c;
			g.drawLine(x0, (int)y0, x1, (int)y1);
			System.out.printf("(%d, %.1f) -- (%d, %.1f)", x0, y0, x1, y1);
		}
	}

	public static void main(String[] args) {
		SwingUtilities.invokeLater(() -> {
			JFrame frame = new JFrame("������");
			frame.add(new Parabola());
			frame.pack();
			frame.setVisible(true);
			frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		});
	}
}