Tower.java

package Q8_06_Towers_of_Hanoi;

import java.util.Stack;

public class Tower {
	private Stack<Integer> disks;
	private int index;
	public Tower(int i) {
		disks = new Stack<Integer>();
		index = i;
	}
	
	public int index() {
		return index;
	}
	
	public void add(int d) {
		if (!disks.isEmpty() && disks.peek() <= d) {
			System.out.println("Error placing disk " + d);
		} else {
			disks.push(d);
		}
	}
	
	public void moveTopTo(Tower t) {
		int top = disks.pop();
		t.add(top);
	}
	
	public void print() {
		System.out.println("Contents of Tower " + index() + ": " + disks.toString());
	}
	
    public void moveDisks(int n, Tower destination, Tower buffer){
		if (n > 0) {
			String tag = "move_" + n + "_disks_from_" + this.index + "_to_" + destination.index + "_with_buffer_" + buffer.index; 
			System.out.println("<" + tag + ">");
			moveDisks(n - 1, buffer, destination);
			System.out.println("<move_top_from_" + this.index + "_to_" + destination.index + ">");
			System.out.println("<before>");
			System.out.println("<source_print>");
			this.print();
			System.out.println("</source_print>");
			System.out.println("<destination_print>");
			destination.print();
			System.out.println("</destination_print>");
			System.out.println("</before>");
			moveTopTo(destination);
			System.out.println("<after>");
			System.out.println("<source_print>");
			this.print();
			System.out.println("</source_print>");
			System.out.println("<destination_print>");
			destination.print();
			System.out.println("</destination_print>");
			System.out.println("</after>");
			System.out.println("</move_top_from_" + this.index + "_to_" + destination.index + ">");
			buffer.moveDisks(n - 1, destination, this);
			System.out.println("</" + tag + ">");
		}
	}
}