import java.awt.*;

public class Polygons {
    public static void main(String[] args) {
        DrawingPanel panel = new DrawingPanel(400,400);
        Graphics2D g = panel.getGraphics();
    }
    public static void fillRegularPolygon(Graphics2D g, int ctrX, int ctrY, int radius, int nPoints) {
        int [] yPoints = new int [nPoints];
        int [] xPoints = new int [nPoints];
        int angle = 360/nPoints;
        int pointCount = 0;

        for (int i = 0; i < 360; i+=angle) {
            double y = ctrY + radius * Math.sin(Math.toRadians(i-90));
            double x = ctrX + radius * Math.cos(Math.toRadians(i-90));
        yPoints[pointCount] = (int)Math.round(y);
        xPoints[pointCount] = (int)Math.round(x);
        pointCount++;
        }
        g.setColor(Color.BLACK);
        g.fillPolygon(xPoints, yPoints, nPoints);
    }
}