/*************************************************************************** * Copyright (C) 2004-2005 by Daniel Clarke * * daniel.jc@gmail.com * * * * This program is free software; you can redistribute it and/or modify * * it under the terms of the GNU General Public License as published by * * the Free Software Foundation; either version 2 of the License, or * * (at your option) any later version. * * * * This program is distributed in the hope that it will be useful, * * but WITHOUT ANY WARRANTY; without even the implied warranty of * * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * * GNU General Public License for more details. * * * * You should have received a copy of the GNU General Public License * * along with this program; if not, write to the * * Free Software Foundation, Inc., * * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * ***************************************************************************/ #ifndef TRAVERSER_H #define TRAVERSER_H #include "btreenode.h" /** Keeps persistant information needed and the algorithm for traversing the binary trees made of BTreeNodes, initialise either by passing a BTreeBase or BTreeNode to traverse a sub tree. Note that this is designed for traversing in the *reverse* way starting at the end of each branch in order to calculate the expression contained in the tree. @author Daniel Clarke */ 00033 class Traverser { public: Traverser(BTreeNode *root); ~Traverser(); /** Find where to start in the tree and return it also resets all the data related to the traversal. */ BTreeNode *start(); /** Finds the next node to move to and returns it. */ BTreeNode *next(); /** Returns true if we are on the left branch, false otherwise. */ bool onLeftBranch(); /** Returns the node on the opposite branch of the parent. */ BTreeNode * oppositeNode(); BTreeNode * current() const { return m_current; } void setCurrent(BTreeNode *current){m_current = current;} /** From the current position, go down the tree taking a left turn always, and stopping when reaching the left terminal node. */ void descendLeftwardToTerminal(); /** It might occur in the future that next() does not just move to the parent, so use this for moving to parent */ void moveToParent(); BTreeNode *root() const {return m_root;} protected: BTreeNode *m_root; BTreeNode *m_current; }; #endif

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