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

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<HTML><HEAD><TITLE>next Method</TITLE></HEAD><BODY bgcolor="#FFFFFF"> <a href="../index.html" target="_top"><img src="../icons/usins.gif" alt="Logo" align=right></a><b>Data Structures and Algorithms with Object-Oriented Design Patterns in Python</b><br><A NAME="tex2html4371" HREF="page276.html"><IMG WIDTH=37 HEIGHT=24 ALIGN=BOTTOM ALT="next" SRC="../icons/next_motif.gif"></A> <A NAME="tex2html4369" HREF="page273.html"><IMG WIDTH=26 HEIGHT=24 ALIGN=BOTTOM ALT="up" SRC="../icons/up_motif.gif"></A> <A NAME="tex2html4365" HREF="page274.html"><IMG WIDTH=63 HEIGHT=24 ALIGN=BOTTOM ALT="previous" SRC="../icons/previous_motif.gif"></A>  <A NAME="tex2html4373" HREF="page611.html"><IMG WIDTH=43 HEIGHT=24 ALIGN=BOTTOM ALT="index" SRC="../icons/index_motif.gif"></A> <BR><HR><H3><A NAME="SECTION009622000000000000000"><tt>next</tt> Method</A></H3><P>Program&nbsp;<A HREF="page273.html#progtreee"><IMG  ALIGN=BOTTOM ALT="gif" SRC="../icons/cross_ref_motif.gif"></A> also defines the <tt>next</tt> methodof the <tt>Tree.Iterator</tt> class.The iterator uses a stack to keep track nodes in the treeto be enumerated.As long as the stack is not empty,the <tt>next</tt> method returnsthe key of the tree node at the top of the stack.The <tt>next</tt> method pops the top tree from the stackand then pushes its subtrees onto the stack (provided that they are not empty).Notice the order is important here.In a preorder traversal, the first subtree of a node is traversedbefore the second subtree.Therefore, the second subtree should appear in the stack <em>below</em>the first subtree.That is why the subtrees are pushed in reverse order.The running time for <tt>next</tt> is <I>O</I>(<I>d</I>) where <I>d</I>is the degree of the tree node at found at the top of the stack.<P><HR><A NAME="tex2html4371" HREF="page276.html"><IMG WIDTH=37 HEIGHT=24 ALIGN=BOTTOM ALT="next" SRC="../icons/next_motif.gif"></A> <A NAME="tex2html4369" HREF="page273.html"><IMG WIDTH=26 HEIGHT=24 ALIGN=BOTTOM ALT="up" SRC="../icons/up_motif.gif"></A> <A NAME="tex2html4365" HREF="page274.html"><IMG WIDTH=63 HEIGHT=24 ALIGN=BOTTOM ALT="previous" SRC="../icons/previous_motif.gif"></A>  <A NAME="tex2html4373" HREF="page611.html"><IMG WIDTH=43 HEIGHT=24 ALIGN=BOTTOM ALT="index" SRC="../icons/index_motif.gif"></A> <P><ADDRESS><img src="../icons/bruno.gif" alt="Bruno" align=right><a href="../copyright.html">Copyright &#169; 2003</a> by <a href="../signature.html">Bruno R. Preiss, P.Eng.</a>  All rights reserved.</ADDRESS></BODY></HTML>

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