public class Hanoi {
     
  public static void hanoi (int n) {
    // Make use of Java's overloading of methods by argument type.
    System.out.println("--------------------------------------------------------");
    System.out.println("Instructions for solving hanoi(" + n + ", A, B, C):");
    hanoi(n, "A", "B", "C");
  }
     
  public static void hanoi (int n, String source, String dest, String spare) {
    if (n > 0)  {
      hanoi(n - 1, source, spare, dest); // Move n-1 disks to spare peg.
      moveDisk(n, source, dest);         // Move largest disk to goal peg.
      hanoi(n - 1, spare, dest, source); // Move n-1 disks to goal peg.
    }
  }
     
  public static void moveDisk (int disk, String source, String dest) {
    // Doesn't actually move a disk, but prints out an instruction to do so. 
    System.out.println("Move disk " + disk + 
		       " from peg " + source + 
		       " to peg " + dest);
  }
     
  public static void main(String [] args) {
    if (args.length != 1) {
      System.out.println("Usage:  java Hanoi n");
      System.exit(-1);
    }
    int n = Integer.parseInt(args[0]);
    hanoi(n);
  }
    
}