Help me a TowersOfHanoi problem

Question

// Lab 3: TowersOfHanoi.java
// Program solves the Towers of Hanoi problem
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class TowersOfHanoi extends JApplet implements ActionListener {
JLabel label;
JTextField input;
JTextArea outputArea;
String output;
public void init()
output = "";
// create components
label = new JLabel( "Enter number of disks ( 1-9 ): " );
input = new JTextField( 5 );
input.addActionListener( this );
outputArea = new JTextArea( 15, 20 );
/* Write code that creates a JScrollPane and attach outputArea to it */
// outputArea.setText( output );
JScrollPane scroll = new JScrollPane(outputArea);
// add components to applet
Container container = getContentPane();
container.setLayout( new FlowLayout() );
/* Write code to add the components to the content pane */
input.addActionListener(this);
container.add(label);
container.add(input);
container.add(scroll);
// recusively move disks through towers
/* write header for method tower */
String tower(int n,String peg1,String peg2,String peg3)
/* Write code here that tests for the base case (i.e., one disk).
In this case, move the last disk from peg 1 to peg 3 and return. */
if(n==1)
return output+="\n"+peg1+"--->"+peg3;
// move ( disks - 1 ) disks from peg1 to peg2 recursively
/* Write a recursive call to method tower that moves
( disks - 1 ) disks from peg1 to peg2 */
else
tower(n-1,peg1,peg3,peg2);
// move last disk from peg1 to peg3 recursively
output += "\n" + peg1 + " --> " + peg3;
// move ( disks - 1 ) disks from peg2 to peg3 recursively
/* Write a recursive call to method tower that moves
( disks - 1 ) disks from peg2 to peg3 */
tower(n-1,peg2,peg1,peg3);
return output;
// actually sort the number of discs specified by user
public void actionPerformed( ActionEvent e )
output = "";
/* call method tower and pass it the number input by the user,
a starting peg of 1, an ending peg of 3 and a temporary peg of 2 */
int n=Integer.parseInt(input.getText());
String peg1="1";
String peg2="2";
String peg3="3";
output+=tower(n,peg1,peg2,peg3);
outputArea.setText( output );
} // end class TowersOfHanoi
when n=3 , its answer : １－－＞３；１－－＞２；３－－＞２；１－－＞３；２－－＞１；２－＞３；１－－＞３
I really don't understand it , Who can explain the operation course of this procedure ? thank you so much!!!

Answer 1

when n=3, the result is 1-->3 , 1-->2, 3-->2,1-->3,
2-->1, 2-->3, 1-->3. I don't
understand 1-->2, 3-->2.It means move the top disk of peg 1 to be on top of
all the disks on peg 2, then move the top disk on peg
3 to be on top of all disks on peg 3.Two, sir.
Signed,
Brother Maynard.