Recursion - Java Software Solutions: Foundations of Program Design - page 599

LISTING 12.4
//********************************************************************
// TowersOfHanoi.java Author: Lewis/Loftus
//
// Represents the classic Towers of Hanoi puzzle.
//********************************************************************
public class TowersOfHanoi
{
private int totalDisks;
//-----------------------------------------------------------------
// Sets up the puzzle with the specified number of disks.
//-----------------------------------------------------------------
public TowersOfHanoi ( int disks)
{
totalDisks = disks;
}
//-----------------------------------------------------------------
// Performs the initial call to moveTower to solve the puzzle.
// Moves the disks from tower 1 to tower 3 using tower 2.
//-----------------------------------------------------------------
public void solve ()
{
moveTower (totalDisks, 1, 3, 2);
}
//-----------------------------------------------------------------
// Moves the specified number of disks from one tower to another
// by moving a subtower of n-1 disks out of the way, moving one
// disk, then moving the subtower back. Base case of 1 disk.
//-----------------------------------------------------------------
private void moveTower ( int numDisks, int start, int end, int temp)
{
if (numDisks == 1)
moveOneDisk (start, end);
else
{
moveTower (numDisks-1, start, temp, end);
moveOneDisk (start, end);
moveTower (numDisks-1, temp, end, start);
}
}