1: #ifndef BINARY_TREE_H
2: #define BINARY_TREE_H
3:
4: /** Class for a binary tree. Updated: 17 November 2008 */
5: #include <cstddef>
6: #include <stdexcept>
7:
8: template<typename Item_Type>
9: class Binary_Tree
10: {
11:
12: protected:
13: //--------------- inner class for node ------------------
14: class BTNode
15: {
16: private:
17: // Data Fields
18: BTNode *_parent, *_left, *_right;
19: Item_Type _data;
20:
21: public:
22:
23: // Constructor
24: BTNode() : _parent(NULL), _left(NULL), _right(NULL) { }
25:
26: // Destructor
27: virtual ˜BTNode() { }
28:
29: Item_Type& data() { return _data; }
30:
31: bool isEnd() const { return this == this->_left; }
32:
33: bool hasParent() const { return _parent != NULL; }
34:
35: BTNode* parent() const { return _parent; }
36:
37: bool hasLeft() const { return !_left->isEnd(); }
38:
39: BTNode* left() const { return _left; }
40:
41: bool hasRight() const { return !_right->isEnd(); }
42:
43: BTNode* right() const { return _right; }
44:
45: bool isLeaf() const { return !(hasLeft() || hasRight()); }
46:
47: BTNode* sibling() { // should not be called upon root
48: if (this == parent->_left)
49: return parent->_right;
50: else
51: return parent->_left;
52: }
53:
54: private:
55: friend class Binary_Tree<Item_Type>; // give access to outer class
56:
57: void linkLeft(BTNode* other) {
58: _left = other;
59: _left->_parent = this;
60: }
61:
62: void linkRight(BTNode* other) {
63: _right = other;
64: _right->_parent = this;
65: }
66:
67: }; // End BTNode
68:
69: private:
70: // data members
71: BTNode* sentinel; // Fixed node used to desginate non-existent children
