// The copyright of this program is reserved by “N”L.
/* 
e^x‚ĚMacLaurin“WŠJ
*/ 

/* <applet code="Ex060924c.class" width=400 height=444> </applet> */

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

public class Ex060924c extends JApplet implements ActionListener{
	boolean flag=false;
	double h=0.01;
  JComboBox cb;
  int num = 0;
  String cbl[]={"n=0","n=1","n=2","n=3","n=4","n=5","n=6"};
  public void init(){
		Container cp =getContentPane();
		JPanel pl = new JPanel();
		pl.setBackground(Color.black);
    cb = new JComboBox(cbl);
    cb.setBounds(0,0,60,20);
    cb.setSelectedIndex(0);
    cb.addActionListener(this);
		pl.setLayout(null);
		pl.add(cb);
		cp.add(pl);
  }
  
  public void actionPerformed(ActionEvent event){
		num = cb.getSelectedIndex()+1; 
		flag=true;
		repaint();
	}
		
	public void paint(Graphics g){
		super.paint(g);
		// g.setColor(Color.blue);
		// g.drawLine(100,300,300,300);
		// g.drawLine(100,0,100,300);
		if(flag==true)
			for(double x=0;x<2.0;x+=h){
		  g.setColor(Color.green);
	 	  g.drawLine((int)(x*200),544-(int)(Math.exp(x)*100),(int)((x+h)*200),544-(int)(Math.exp(x+h)*100));
	 	  g.setColor(Color.red);
			g.drawLine((int)(x*200),544-(int)(ex(num,x)*100),(int)((x+h)*200),544-(int)(ex(num,x+h)*100));
			}	
	}
	
	// exp(x)‚ĚMacLaurin“WŠJ
	public double ex(int n, double x){
		double val=0.0;
		for(int i=0;i<n;i++)
			val+=Math.pow(x,(double)i)/(double)rec(i);
		return(val);
	}
	
	public int rec(int num){
		if(num == 0 || num==1)
			return(1);
		else
			return(num*rec(num-1));	
	}
}