Method add

java/Chapter 3/Question3_4/Tower.java:17–23

(int d)

	}
	
	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();