#
# This software is Copyright 2005 by Elsevier Inc.  You may use it
# under the terms of the license at http://perl.plover.com/hop/LICENSE.txt .
#



###
### hanoi
###

## Chapter 1 section 3

# hanoi(N, start, end, extra)
# Solve Tower of Hanoi problem for a tower of N disks,
# of which the largest is disk #N.  Move the entire tower from
# peg `start' to peg `end', using peg `extra' as a work space
  
sub hanoi {
  my ($n, $start, $end, $extra) = @_;
  if ($n == 1) { 
    print "Move disk #1 from $start to $end.\n";  # Step 1
  } else {
    hanoi($n-1, $start, $extra, $end);            # Step 2
    print "Move disk #$n from $start to $end.\n"; # Step 3
    hanoi($n-1, $extra, $end, $start);            # Step 4
  }
}