[转]二叉树的实现
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实现的二叉树类提供了如下功能 1：由前序字串生成二叉树 2：由后续字串生成二叉树 3：提供三种迭代器，用于遍历二叉树 文件 test.cpp 是对二叉树接口的测试，文件BinaryTree.h是二叉树模板的实现，其中用到了链栈，myStack.h 在以前的文章提到过，并且也提供了代码
在BinaryTree.h 定义了几个类 BinTreeNode ：二叉树节点类,带父节点 BinaryTree ： 二叉树类 BinaryTree::iterator; //迭代器基类 BinaryTree::PreOrder_iterator; //前序迭代器 BinaryTree::InOrder_iterator; //中序迭代器 BinaryTree::PostOrder_iterator; //后序迭代器 * Copyright (c) 2006 * Jacky Wu * You can use these source code for any purpose. * And It is provided "as is" without express or implied warranty. * * 你可以任意使用该代码，但是本人不对代码的安全性做任何担保！！！ * * 由于大部分代码是出于学习目的实现的，只是让它“可以使用"， * 并没有经过安全性，高负荷运行强度等测试，我必须对这些代码做一个声明： * ！！！！ * 免责声明： * 对于使用在本blog上提供的任意“形式”(包括测试，类的实现， * 系统的分析 等等只要是代码片断）的代码造成系统不稳定或者 * 由于此造成的经济、声誉上的损失，或者是人身伤害等任何损失，本人不负任何法律责任
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//文件 test.cpp
#include "BinaryTree.h"
#include <iostream>
using namespace std;
int main() { BinaryTree<char> tree;
//前序字符串 string str = "ABC#D##E#F##GH#I##JK##L##";
//后续字符串 //string str = "###DC###FEB###IH##K##LJGA";
//前序方法生成二叉树 tree.PreOrderCreateTree(str);
cout << "EXP STR: " << str << endl;
//前序方法遍历打印二叉树 tree.PreOrder();
//中序打印二叉树 tree.InOrder();
//后续打印二叉树 tree.PostOrder();
cout << "Tree Height:" << tree.Height() << endl; cout << "Tree Height:" << tree.Size() << endl;
//二叉树拷贝构造调用 BinaryTree<char> tree2 = tree; tree2.PreOrder();
cout << "PreOrder iteraotr!/n";
//二叉树前序迭代器 BinaryTree<char>::PreOrder_iterator preiter(tree2); while(!preiter.IsEnd()) {
cout << *preiter << ","; ++preiter; } cout << endl;
//二叉树中序迭代器 tree.InOrder(); cout << "InOrder iteraotr!/n"; BinaryTree<char>::InOrder_iterator initer(tree2); while(!initer.IsEnd()) {
cout << *initer << ","; ++initer; }
//二叉树后续迭代器 cout << endl; tree2.PostOrder(); cout << "PostOrder iteraotr!/n"; BinaryTree<char>::PostOrder_iterator postiter(tree2);
while(!postiter.IsEnd()) {
cout << *postiter << ","; ++postiter; }
return 0; } |
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//文件BinaryTree.h
#ifndef BINARYTREE_H_ #define BINARYTREE_H_
#include "myStack.h"
#include <string> #include <iostream> #include <stdexcept>
enum ChildID { LEFTCHILD = 0, RIGHTCHILD }; //子节点类型，是左节点还是右节点
template <class Type> class BinaryTree;
//愚认为，如果BinTreeNode中的数据需要让大部分用户访问的话，应当是struct型 template <class Type> class BinTreeNode { friend class BinaryTree< Type >; public: BinTreeNode() : m_pParent(0), m_plChild(0), m_prChild(0){}
BinTreeNode( Type item, BinTreeNode<Type> *parent = 0, BinTreeNode<Type> *left = 0, BinTreeNode<Type> *right = 0 ) : m_pParent(parent), m_plChild(left), m_prChild(right), m_data(item) {}
Type GetData() const; //获取节点保存的数据 Type& GetDataRef(); //不应当提供这样的接口，这里仅仅让iterator能够自由访问存储的数据 BinTreeNode* GetParent() const; //获取节点的父节点 BinTreeNode* GetLeft() const; //获取节点的左子节点 BinTreeNode* GetRight() const; //获取节点的右子节点
void SetData( const Type& data ); //修改节点的数据
//下面是更改节点的指针域结构的function，是否真的需要，还得仔细考量 //做为树的节点，一般不允许直接访问节点中的指针数据，如果这些数据在树 //被建立完成以后修改，会破坏树的结构
void SetParent( BinTreeNode<Type>* parent, ChildID CHID ); //设置当前节点的父节点，并指定当前节点作为子节点的类型 void SetLeft( BinTreeNode<Type>* left); //设置当前节点的左子节点 void SetRight( BinTreeNode<Type>* right); //设置当前节点的右子节点
private: BinTreeNode< Type >* m_pParent; //父节点 BinTreeNode< Type >* m_plChild; //left Child BinTreeNode< Type >* m_prChild; //right Child Type m_data; }; //declare BinTreeNode end
//********************************************************* // BinTreeNode Implementation //********************************************************* template <class Type> Type BinTreeNode<Type>::GetData() const { return m_data; }
template <class Type> Type& BinTreeNode<Type>::GetDataRef() { return m_data; }
template <class Type> BinTreeNode<Type>* BinTreeNode<Type>::GetParent() const { return m_pParent; }
template <class Type> BinTreeNode<Type>* BinTreeNode<Type>::GetLeft() const { return m_plChild; }
template <class Type> BinTreeNode<Type>* BinTreeNode<Type>::GetRight() const { return m_prChild; }
template <class Type> void BinTreeNode<Type>::SetData( const Type& data ) { m_data = data; }
template <class Type> void BinTreeNode<Type>::SetParent( BinTreeNode<Type>* parent, ChildID CHID ) { if( !parent ) return;
if( CHID == m_plChild ) //当前节点作为parent的左子节点 { m_pParent = parent; parent->m_plChild = this; } else if( CHID == RIGHTCHILD ) //当前节点作为parent的右子节点 { m_pParent = parent; parent->m_prChild = this; } }
template <class Type> void BinTreeNode<Type>::SetLeft( BinTreeNode<Type>* left) { m_plChild = left; }
template <class Type> void BinTreeNode<Type>::SetRight( BinTreeNode<Type>* right) { m_prChild = right; }
// BinTreeNode Implementation over //********************************************************* //*********************************************************
template <class Type> class BinaryTree { public: BinaryTree() : root(NULL) {} BinaryTree( Type value) : RefValue(value), root(NULL) {}
BinaryTree( const BinaryTree<Type>& tree); //copy Constructure privated BinaryTree<Type>& operator=( const BinaryTree<Type>& tree); //operator= privated
virtual ~BinaryTree(); virtual int IsEmpty() { return root == NULL; }
/* * 下面三个函数的可用性，返回值类型的正确性值得考量 * 这样做不仅会破坏树的结构，而且很容易引起内存泄漏 * 在一般的树中最好不要提供这三个接口 */ virtual BinTreeNode<Type>* Parent( BinTreeNode<Type>* current ); //返回所给结点父结点
virtual BinTreeNode<Type>* LeftChild( BinTreeNode<Type>* current); //返回节点的左子积极淡
virtual BinTreeNode<Type>* RightChild( BinTreeNode<Type>* current); //返回节点的右子女
virtual bool Insert( const Type& item); //插入元素 virtual bool Find( const Type& item) const; //搜索元素
const BinTreeNode<Type>* GetRoot() const; //取树根
//遍历操作 void PreOrder() const; //前序 void InOrder() const; //中序 void PostOrder() const; //后序
//二叉树特性操作函数 int Size() const; int Size( const BinTreeNode<Type>* troot) const; int Height() const; int Height( const BinTreeNode<Type>* troot) const; bool operator==( const BinaryTree<Type>& tree) const;
//下面的接口是以不同的方式来构建二叉树 BinaryTree<Type>& AutoCreateTree(const std::string& expstr); //自动判断格式并建立 BinaryTree<Type>& PreOrderCreateTree(const std::string& expstr); //先序建立 BinaryTree<Type>& PostOrderCreateTree(const std::string& expstr); //后续建立
protected: BinTreeNode< Type>* Parent( BinTreeNode<Type>* start, BinTreeNode<Type>* current ); int Insert( BinTreeNode<Type>* current, const Type& item); void Travers( BinTreeNode<Type>* current, std::ostream& out ) const; void Find( BinTreeNode<Type>* current, const Type& item ) const; void destroy( BinTreeNode<Type>* current);
//遍历递归 void InOrder( BinTreeNode<Type>* current) const; void PreOrder( BinTreeNode<Type>* current ) const; void PostOrder( BinTreeNode<Type>* current) const;
//二叉树特性递归操作函数 BinTreeNode<Type>* Copy( BinTreeNode<Type>* troot, BinTreeNode<Type>* parent); bool equal( BinTreeNode<Type>* troot1, BinTreeNode<Type>* troot2) const;
//建树用的递归函数 BinTreeNode<Type>* PreOrderCreateNode(const char* &expstr, BinTreeNode<Type>* parent); //先序递归建立二叉树 BinTreeNode<Type>* PostOrderCreateNode(const char* &expstr, BinTreeNode<Type>* parent); //后续递归建立二叉树
//声明一组用于二叉树的迭代器iterator private: class iterator; //迭代器基类 friend class iterator; public:
class PreOrder_iterator; //前序迭代器 class InOrder_iterator; //中序迭代器 class PostOrder_iterator; //后序迭代器 class LevelOrder_iterator; //层序迭代器
friend class PreOrder_iterator; friend class InOrder_iterator; friend class PostOrder_iterator; friend class LevelOrder_iterator;
private: BinTreeNode< Type >* root; //树的根指针 Type RefValue; //数据输入终结标志 }; //END BinaryTree
/********************************** * implament of template BinaryTree * **********************************/
template <class Type> BinaryTree<Type>::BinaryTree( const BinaryTree<Type>& tree) //copy Constructure privated { root = Copy(tree.root, NULL); }
template <class Type> BinaryTree<Type>& BinaryTree<Type>::operator=( const BinaryTree<Type>& tree) //operator= privated { destroy(root); root = Copy(tree.root, NULL); return *this; }
template <class Type> BinaryTree<Type>::~BinaryTree() { destroy(root); //遍历删除二叉树 }
template <class Type> bool BinaryTree<Type>::Insert( const Type& item) {
return true; }
template <class Type> bool BinaryTree<Type>::Find( const Type& item) const { return true; }
template <class Type> BinTreeNode<Type>* BinaryTree<Type>::Parent( BinTreeNode<Type>* current) { if( root == NULL || root == current ) { return NULL; } else { return current->m_pParent; }
/* * 由于节点保留了parent的地址，所以可以直接取得父节点的地址 * 但是节点中如果没有parent的数据，就必须调用递归查询来寻找父节点的地址 * 代码片断如下，它调用了Parent( BinTreeNode<Type> *start, BinTreeNode<Type>* current)
return (root == NULL || root == current) ? NULL : Parent( root, current);
*/ }
template <class Type> BinTreeNode<Type>* BinaryTree<Type>::LeftChild( BinTreeNode<Type>* current) { return current != NULL ? current->m_plChild : NULL; }
template <class Type> BinTreeNode<Type>* BinaryTree<Type>::RightChild( BinTreeNode<Type>* current) { return current != NULL ? current->m_prChild : NULL; }
template <class Type> BinTreeNode<Type>* BinaryTree<Type>::Parent( BinTreeNode<Type> *start, BinTreeNode<Type>* current) { //从结点start开始，搜索节点current的父结点， //如果找到其父节点，则函数将其返回，否则返回 NULL if( !start ) return NULL; if( start->m_plChild == current || start->m_prChild == current) return start;
BinTreeNode<Type> *pNode; if((pNode = Parent( start->m_plChild, current)) != NULL) { return pNode; } else { return Parent( start->m_prChild, current); } }
template <class Type> const BinTreeNode<Type>* BinaryTree<Type>::GetRoot() const { return root; }
template <class Type> void BinaryTree<Type>::Travers( BinTreeNode<Type>* current, std::ostream& out) const { //前序输出根为current的二叉数 if( current ) { out << current->m_data; Travers( current->m_plChild , out ); Travers( current->m_prChild, out ); } else { out<<"#"; } }
//中序遍历操作 template <class Type> void BinaryTree<Type>::InOrder() const { std::cout << "InOrder Traval Tree:/n"; InOrder( root ); std::cout << std::endl; }
template <class Type> void BinaryTree<Type>::InOrder( BinTreeNode<Type>* current) const { //递归私有函数，中序遍历二叉树 if(current != NULL) { InOrder(current->m_plChild); std::cout << current->m_data; InOrder(current->m_prChild); } else { std::cout << "#"; } }
//前序遍历操作 template <class Type> void BinaryTree<Type>::PreOrder() const { std::cout << "PreOrder Travel Tree:/n"; PreOrder (root); std::cout << std::endl; }
template <class Type> void BinaryTree<Type>::PreOrder( BinTreeNode<Type>* current) const { if(current != NULL) { std::cout << current->m_data; PreOrder(current->m_plChild); PreOrder(current->m_prChild); } else { std::cout <<"#"; } }
//后序遍历操作 template <class Type> void BinaryTree<Type>::PostOrder() const { //后序遍历 std::cout << "PostOrder Travel Tree:/n"; PostOrder(root); std::cout << std::endl; }
template <class Type> void BinaryTree<Type>::PostOrder( BinTreeNode<Type>* current) const{ //后序递归操作
if( current != NULL ) { PostOrder(current->m_plChild); PostOrder(current->m_prChild); std::cout << current->m_data; } else { std::cout << "#"; } }
//计算二叉树的结点数 template <class Type> int BinaryTree<Type>::Size() const { return Size(root); }
template <class Type> int BinaryTree<Type>::Size( const BinTreeNode<Type>* troot) const { if(troot == NULL) return 0; //空树,返回0 else return 1 + Size(troot->m_plChild) + Size(troot->m_prChild);
}
//计算二叉树的高度 template <class Type> int BinaryTree<Type>::Height() const { return Height(root); }
template <class Type> int BinaryTree<Type>::Height( const BinTreeNode<Type>* troot) const { if ( troot == NULL ) return -1; else return 1 + MAX( Height( troot->m_plChild ) , Height( troot->m_prChild) ); }
//用于递归拷贝的私有函数 template <class Type> BinTreeNode<Type>* BinaryTree<Type>::Copy( BinTreeNode<Type>* troot, BinTreeNode<Type>* parent) { if (NULL == troot) return NULL; BinTreeNode<Type>* pNode = new BinTreeNode<Type>; pNode->m_data = troot->m_data; //拷贝数据 pNode->m_pParent = parent; pNode->m_plChild = Copy( troot->m_plChild, pNode ); //新建左子树 pNode->m_prChild = Copy( troot->m_prChild, pNode ); //新建右子树 return pNode; //返回树根结点 }
//判断二叉树内容是否相等 template <class Type> bool BinaryTree<Type>::operator==( const BinaryTree<Type>& tree) const { return equal( root, tree.root ); }
//判断二叉树相等的递归操作 template <class Type> bool BinaryTree<Type>::equal( BinTreeNode<Type>* troot1, BinTreeNode<Type>* troot2) const { if( NULL == troot1 && NULL == troot2 ) return true; if( (NULL == troot1 && NULL != troot2) || (NULL != troot1 && NULL == troot2) || (troot1->data != troot2->data) ) { return false; } else { return equal( troot1->m_plChild, troot2->m_plChild) && equal( troot1->m_prChild, troot2->m_prChild); } return true; }
template <class Type> void BinaryTree<Type>::destroy( BinTreeNode<Type>* current) { if( current ) { destroy( current->m_plChild ); //递归删除左结点 destroy( current->m_prChild); //除右节点 delete current; current = NULL; //空置指针 } }
//define of Max function template <class _T> _T MAX(const _T& a, const _T& b) { return (a>=b) ? a : b; }
//********************************************************* //1:先序方式建立二叉树
template <class Type> BinaryTree<Type>& BinaryTree<Type>::PreOrderCreateTree(const std::string& expstr) { using namespace std;
const char* exp = expstr.c_str(); if(*exp != '#') //以#开头表示字符串不是先序表达式 { destroy(root); root = PreOrderCreateNode(exp, NULL); } else { cout << "Your string expression error, I can't Create B-Tree :)/n"; }
return *this; }
template <class Type> BinTreeNode<Type>* BinaryTree<Type>::PreOrderCreateNode(const char* &expstr, BinTreeNode<Type>* parent) { if( *expstr == '#' || *expstr == '/0') return NULL; BinTreeNode<Type>* pnewNode = new BinTreeNode<Type>(*expstr, parent);
assert(pnewNode);
pnewNode->m_plChild = PreOrderCreateNode(++expstr, pnewNode); pnewNode->m_prChild = PreOrderCreateNode(++expstr, pnewNode); return pnewNode; }
//*********************************************************
//*********************************************************
//3：后续方式建立二叉树 template <class Type> BinaryTree<Type>& BinaryTree<Type>::PostOrderCreateTree(const std::string& expstr) { using namespace std; const char* exp = expstr.c_str(); if( expstr.size() < 3) { destroy(root); return *this; }
if(*exp == '#' && *(exp+1) == '#' && *(exp+2) == '#' ) //以 ##'X' 开头表示字符串是后续序表达式 'X'表示元素 { destroy(root); exp += expstr.size()-1; root = PostOrderCreateNode(exp, NULL); //反向遍历生成 } else { cout << "Your string expression error, I can't Create B-Tree :)/n"; }
return *this;
}
template <class Type> BinTreeNode<Type>* BinaryTree<Type>::PostOrderCreateNode(const char* &expstr, BinTreeNode<Type>* parent) { if( *expstr == '#') return NULL; BinTreeNode<Type>* pnewNode = new BinTreeNode<Type>(*expstr, parent);
assert(pnewNode); pnewNode->m_prChild = PostOrderCreateNode(--expstr, pnewNode);
pnewNode->m_plChild = PostOrderCreateNode(--expstr, pnewNode);
return pnewNode; }
//******************************************************** //******************************************************** //三种迭代器的实现
//iterator 是私有的基类迭代器,这里没有实现常量树的迭代器 const_iterator //这样做确保了用户不可能访问到这个迭代器 template <class Type> class BinaryTree<Type>::iterator { public: iterator():m_btree(NULL), m_pCurrent(NULL){} virtual ~iterator() {}
virtual iterator& operator= (const iterator& iter) { m_pCurrent = iter.m_pCurrent; return *this; }
virtual iterator& GotoFirst() = 0; //游标索引到第一个节点 virtual bool IsEnd() = 0; //游标是否已经索引到末尾
virtual iterator& operator++() = 0; // 游标自增 //virtual iterator operator++(int) = 0;
virtual const Type& current() const; virtual Type& operator*(); virtual Type* operator->(); protected: BinaryTree<Type>* m_btree; BinTreeNode<Type>* m_pCurrent; };
template <class Type> const Type& BinaryTree<Type>::iterator::current() const { if(m_pCurrent != NULL) { return m_pCurrent->GetDataRef(); } else { throw std::out_of_range("iterator error/n"); } }
template <class Type> Type& BinaryTree<Type>::iterator::operator*() { if(m_pCurrent != NULL) { return m_pCurrent->GetDataRef(); } else { throw std::out_of_range("iterator error/n"); } }
template <class Type> Type* BinaryTree<Type>::iterator::operator->() { if(m_pCurrent != NULL) { return &(m_pCurrent->GetDataRef()); } else { throw std::out_of_range("iterator error/n"); }
}
//********************************************************* //这里采用两种方式来遍历树 //1:采用简单计数栈的非递归遍历（要求结点中有父节点数据域） //2：采用栈的非递归遍历（在最后注释部分） //*********************************************************
//前序遍历迭代器(无栈)
template <class Type> class BinaryTree<Type>::PreOrder_iterator : public iterator { using iterator::m_pCurrent; using iterator::m_btree; public: PreOrder_iterator() {} PreOrder_iterator(const BinaryTree<Type>& tree ) { m_btree = const_cast< BinaryTree<Type>* >(&tree); GotoFirst(); //索引至第一个结点 }
PreOrder_iterator(const PreOrder_iterator& iter) { m_btree = iter.m_btree; m_pCurrent = iter.m_pCurrent; }
PreOrder_iterator& GotoFirst() { stk.MakeEmpty(); if(m_btree == NULL) { stk.MakeEmpty(); m_pCurrent = NULL; } else { m_pCurrent = const_cast< BinTreeNode<Type>* >(m_btree->GetRoot()); //强制转换为非常量指针 stk.Push(1); //记录当前树的根节点访问次数 } return *this; }
bool IsEnd() { return m_pCurrent == NULL; }
PreOrder_iterator& operator++() ; // 游标自增 //PreOrder_iterator operator++(int);
private: ChainStack<int> stk; //保存访问节点的遍历次数的栈 };
template <class Type> typename BinaryTree<Type>::PreOrder_iterator& BinaryTree<Type>::PreOrder_iterator::operator++() //前序后继节点 { if( stk.IsEmpty() ) //确保迭代器是有效的 { return *this; }
//访问左子节点
if( m_pCurrent->GetLeft() == NULL) //左节点无效 { stk.Pop(); stk.Push(2); //m_pCurrent 第二次访问
//查询右节点 if( m_pCurrent->GetRight() == NULL) //右节点也无效 { //回溯搜索有效的节点 while( !stk.IsEmpty() && stk.Pop()==2 ) { m_pCurrent = m_pCurrent->GetParent(); }
stk.Push(1); //节点的右子节点不可访问,继续回溯,搜索到跟节点,停止搜索 while(m_pCurrent != NULL && m_pCurrent->GetRight() == NULL ) { m_pCurrent = m_pCurrent->GetParent(); stk.Pop(); }
//如果已经搜索出根节点,抛出异常 if(m_pCurrent == NULL) { //throw std::out_of_range("BinaryTree iterator over/n"); } else { stk.Pop(); stk.Push(2); //m_pCurrent访问计数2
m_pCurrent = m_pCurrent->GetRight(); stk.Push(1); } } else //右节点有效 { m_pCurrent = m_pCurrent->GetRight(); stk.Push(1); } } else //左节点有效 { m_pCurrent = m_pCurrent->GetLeft(); stk.Push(1); } return *this; }
//中序遍历迭代器 //InOrder_iterator
template <class Type> class BinaryTree<Type>::InOrder_iterator : public iterator { using iterator::m_pCurrent; using iterator::m_btree; public: InOrder_iterator() {} InOrder_iterator(const BinaryTree<Type>& tree ) { m_btree = const_cast< BinaryTree<Type>* >(&tree); GotoFirst(); //索引至第一个结点 }
InOrder_iterator(const PreOrder_iterator& iter) { m_btree = iter.m_btree; m_pCurrent = iter.m_pCurrent; }
InOrder_iterator& GotoFirst() { stk.MakeEmpty(); if(m_btree == NULL) { stk.MakeEmpty(); m_pCurrent = NULL; } else { m_pCurrent = const_cast< BinTreeNode<Type>* >(m_btree->GetRoot()); if( m_pCurrent != NULL ) { stk.Push(1); //节点计数进1 while( m_pCurrent->GetLeft() != NULL ) { m_pCurrent = m_pCurrent->GetLeft(); stk.Push(1); } } } return *this; }
bool IsEnd() { return m_pCurrent == NULL; }
InOrder_iterator& operator++() // 游标自增1 { if(IsEnd()) { return *this; }
if( m_pCurrent->GetRight() == NULL) { stk.Pop(); stk.Push(2); while( !stk.IsEmpty() && stk.Pop() == 2) { m_pCurrent = m_pCurrent->GetParent(); } stk.Push(2); return *this; } else { //右节点有效 stk.Pop(); stk.Push(2); m_pCurrent = m_pCurrent->GetRight(); stk.Push(1);
while( m_pCurrent->GetLeft() != NULL) { m_pCurrent = m_pCurrent->GetLeft(); stk.Push(1); } } return *this; } //InOrder_iterator operator++(int);
private: ChainStack<int> stk; //保存访问节点的遍历次数的栈
};
//********************************************************** //后序遍历迭代器 //PostOrder_iterator template <class Type> class BinaryTree<Type>::PostOrder_iterator : public iterator { using iterator::m_pCurrent; using iterator::m_btree; public: PostOrder_iterator() {} PostOrder_iterator(const BinaryTree<Type>& tree ) { m_btree = const_cast< BinaryTree<Type>* >(&tree); GotoFirst(); //索引至第一个结点 }
PostOrder_iterator(const PreOrder_iterator& iter) { m_btree = iter.m_btree; m_pCurrent = iter.m_pCurrent; }
PostOrder_iterator& GotoFirst() { stk.MakeEmpty(); if(m_btree == NULL) { stk.MakeEmpty(); m_pCurrent = NULL; } else { m_pCurrent = const_cast< BinTreeNode<Type>* >(m_btree->GetRoot()); if( m_pCurrent != NULL ) { stk.Push(1); //节点计数进1 while( m_pCurrent->GetLeft() != NULL || m_pCurrent->GetRight() != NULL) { if( m_pCurrent->GetLeft() != NULL) { m_pCurrent = m_pCurrent->GetLeft(); stk.Push(1); } else if( m_pCurrent->GetRight() != NULL) { stk.Pop(); stk.Push(2); m_pCurrent = m_pCurrent->GetRight(); stk.Push(1); } } } } return *this; }
bool IsEnd() { return m_pCurrent == NULL; }
PostOrder_iterator& operator++() // 游标自增1 { if(IsEnd()) { return *this; }
if( m_pCurrent->GetRight() == NULL || stk.GetTop() ==2) { m_pCurrent = m_pCurrent->GetParent(); stk.Pop(); } if( m_pCurrent != NULL && m_pCurrent->GetRight() != NULL && stk.GetTop() ==1) { //父节点存在右节点,且并未访问过 stk.Pop(); stk.Push(2); m_pCurrent = m_pCurrent->GetRight(); stk.Push(1); while( m_pCurrent->GetLeft() != NULL || m_pCurrent->GetRight() !=NULL) { if( m_pCurrent->GetLeft() != NULL) { m_pCurrent = m_pCurrent->GetLeft(); stk.Push(1); } else if( m_pCurrent->GetRight() != NULL) { stk.Pop(); stk.Push(2); m_pCurrent = m_pCurrent->GetRight(); stk.Push(1); } } } return *this; }
private: ChainStack<int> stk; //保存访问节点的遍历次数的栈 };
#endif /*BINARYTREE_H_*/ |
