class GJpanel extends JPanel {
        private int w;
        private int h;
        public GJpanel(){

        }
        

        public void paintComponent(final Graphics g){
            w = getWidth();
            h = getHeight();
            g.setColor(Color.green);
            g.drawLine(0, 0, 0,getHeight());            
            g.setColor(Color.red);
            g.drawLine(0,h/2,w,h/2);  //x
            g.drawLine(w, h/2, w-10, h/2-10);
            g.drawLine(w, h/2, w-10, h/2+10);
            g.drawLine(w/2, 0,w/2, h); //y
            g.drawLine(w/2, 0, w/2-10, 10);
            g.drawLine(w/2, 0, w/2+10, 10);
            g.drawString("Y", w/2-20, 20);
            g.drawString("X", w-20, h/2+20);
            for(int x =0;x<w; x++){
                 int y =(int) (Math.cos (x*Math. PI/180)*h/3+h/2);
                g.drawString("·", x, y);
            }
}