import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class yuxian extends JFrame implements ComponentListener,ItemListener
{
    p rivate JComboBox combobox_color;
    public yuxian()
    {
        super("");
        this.setSize(500,500);
        this.setDefaultCloseOperation(EXIT_ON_CLOSE);
        this.setLayout(new FlowLayout());
        
        Object data[]={Color.red,Color.green,Color.blue};
        combobox_color=new JComboBox(data);
        combobox_color.addItemListener(this);
        this.add(combobox_color);
        
        this.addComponentListener(this);
        this.setVisible(true);
    }
    public void paint(Graphics g)
    {        g.setColor((Color)combobox_color.getSelectedItem());
        double f(double x) 
        {  
          return (Math.cos(x/12.0)*200.0/4+100);  
        }  
        for(int x=0;x<this.getWidth();x++)
        {
            g.drawLine(x,(int)f(x),x+1,(int)f(x+1));
        }
    }
    public void itemStateChanged(ItemEvent e)
    {
        repaint();
    }
    public void componentResized(ComponentEvent e)
    {
        repaint();
    }
    public void componentMoved(ComponentEvent e){}
    public void componentHidden(ComponentEvent e){}
    public void componentShown(ComponentEvent e){}
    public static void main(String arg[])
    {
        new yuxian();
    }
}