pgm09_09.txt

Data Structures And Algorithms With Object-Oriented Design Patterns In Python (2003) source code and

#
# This file contains the Python code from Program 9.9 of
# "Data Structures and Algorithms
# with Object-Oriented Design Patterns in Python"
# by Bruno R. Preiss.
#
# Copyright (c) 2003 by Bruno R. Preiss, P.Eng.  All rights reserved.
#
# http://www.brpreiss.com/books/opus7/programs/pgm09_09.txt
#
class Tree(Container):

    class Iterator(Iterator):

        def __init__(self, tree):
            super(Tree.Iterator, self).__init__(tree)
            self._stack = StackAsLinkedList()
	    if not tree.isEmpty:
		self._stack.push(tree)

        def next(self):
            if self._stack.isEmpty:
		raise StopIteration
	    top = self._stack.pop()
	    i = top.degree - 1
	    while i >= 0:
		subtree = top.getSubtree(i)
		if not subtree.isEmpty:
		    self._stack.push(subtree)
		i -= 1
            return top.key

    def __iter__(self):
        return Tree.Iterator(self)

    # ...