C++链表实现二叉树

我们分别在node.h和tree.h中定义了树中的节点类和树类，同时在node.cpp和tree.cpp中实现了在头文件中申明的函数，然后在demo.cpp中创建一棵树，看看效果。

PS：注意searchIndex（pos）函数，深刻理解其内在递归性，要不超容易犯错，博主初学的时候就是没有仔细理解其递归性，导致遍历一直出错，花了好长时间才找到问题出在哪里，非常耗时。

node.h

#ifndef NODE_H
#define NODE_H
class Node{
public:
Node();
int pos;
int data;
Node* p_lchild;
Node* p_rchild;
Node* p_parent;
bool addNode(int pos, int direction, Node* pNode);
void delNode();
void preOrderTraverse();
void inOrderTraverse();
void postOrderTraverse();
Node* searchIndex(int pos);
};

#endif

tree.h

#ifndef TREE_H
#define TREE_H
#include "node.h"
class Tree{
pub
4000
lic:
Tree();
~Tree();
Node* searchIndex(int index);
bool addNode(int pos,int direction,Node* pNode);
void delNode(int pos, Node* pNode);
void preOrderTraverse();
void inOrderTraverse();
void postOrderTraverse();
private:
Node* m_proot;
};

#endif

node.cpp

#include "node.h"
#include <iostream>
using namespace std;

Node::Node(){
this->pos = 0;
this->data = 0;
this->p_lchild = NULL;
this->p_rchild = NULL;
this->p_parent = NULL;
}
Node* Node::searchIndex(int pos)
{
if (this->pos==pos){
cout << "搜索到了：" << this->pos << endl;
return this;
}

Node* temp = NULL;
if (this->p_lchild != NULL){
if (this->p_lchild->pos == pos){
cout << "搜索到了：" << this->p_lchild->pos << endl;
return this->p_lchild;
}
else{
temp=this->p_lchild->searchIndex(pos);
if (temp != NULL){
return temp;
}
}
}
if (this->p_rchild != NULL){
if (this->p_rchild->pos == pos){
cout << "搜索到了：" << this->p_rchild->pos<<endl;
return this->p_rchild;
}
else{
return this->p_rchild->searchIndex(pos);
}
}
return NULL;
}
bool Node::addNode(int pos, int direction, Node* pNode)
{
Node *p_parent = searchIndex(pos);
if (p_parent == NULL){
return false;
}
Node *cur = new Node();
if (cur == NULL){
return false;
}
cur->pos = pNode->pos;
cur->data = pNode->data;
if (direction == 0){
if (p_parent->p_lchild != NULL){
return false;
}
p_parent->p_lchild = cur;
cur->p_parent = p_parent;
cout << p_parent->pos << "的左孩子是：" << cur->pos << endl;
}
if (direction == 1){
if (p_parent->p_rchild != NULL){
return false;
}
p_parent->p_rchild = cur;
cur->p_parent = p_parent;
cout << p_parent->pos << "的右孩子是：" << cur->pos << endl;
}
return true;
}
void Node::delNode()
{
if (this->p_lchild != NULL){
this->p_lchild->delNode();
}
if (this->p_rchild != NULL){
this->p_rchild->delNode();
}
if (this->p_parent != NULL){
if (this->p_parent->p_lchild == this){
this->p_parent->p_lchild = NULL;
}
if (this->p_parent->p_rchild == this){
this->p_parent->p_rchild = NULL;
}
}
}
void Node::preOrderTraverse()
{
cout << this->pos << ":" << this->data << endl;
if (this->p_lchild != NULL){
this->p_lchild->preOrderTraverse();
}
if (this->p_rchild != NULL){
this->p_rchild->preOrderTraverse();
}
}
void Node::inOrderTraverse()
{
if (this->p_lchild != NULL){
this->p_lchild->inOrderTraverse();
}
cout << this->pos << ":" << this->data << endl;
if (this->p_rchild != NULL){
this->p_rchild->inOrderTraverse();
}
}
void Node::postOrderTraverse()
{
if (this->p_lchild != NULL){
this->p_lchild->postOrderTraverse();
}
if (this->p_rchild != NULL){
this->p_rchild->postOrderTraverse();
}
cout << this->pos << ":" << this->data << endl;
}

tree.cpp

#include "tree.h";
#include <iostream>
using namespace std;

Tree::Tree()
{
m_proot = new Node();
}
Tree::~Tree(){
delNode(0, NULL);
}
Node* Tree::searchIndex(int index)
{
return m_proot->searchIndex(index);
}
bool Tree::addNode(int pos, int direction, Node* pNode)
{
return m_proot->addNode(pos, direction, pNode);
}
void Tree::delNode(int pos, Node* pNode)
{
Node* cur = searchIndex(pos);
cur->delNode();
}
void Tree::preOrderTraverse()
{
m_proot->preOrderTraverse();
}
void Tree::inOrderTraverse()
{
m_proot->inOrderTraverse();
}
void Tree::postOrderTraverse()
{
m_proot->postOrderTraverse();
}

demo.cpp

#include <iostream>
#include "tree.h"
using namespace std;

int main(){
Node* node1 = new Node();
node1->pos = 1;
node1->data = 5;

Node* node2 = new Node();
node2->pos = 2;
node2->data = 8;

Node* node3 = new Node();
node3->pos = 3;
node3->data = 2;

Node* node4 = new Node();
node4->pos = 4;
node4->data = 6;

Node* node5 = new Node();
node5->pos = 5;
node5->data = 9;

Node* node6 = new Node();
node6->pos = 6;
node6->data
12b21
= 7;

Tree* tree = new Tree();
tree->addNode(0, 0, node1);
tree->addNode(0, 1, node2);
tree->addNode(1, 0, node3);
tree->addNode(1, 1, node4);
tree->addNode(2, 0, node5);
tree->addNode(2, 1, node6);

cout << "前序遍历：" << endl;
tree->preOrderTraverse();
cout << "中序遍历：" << endl;
tree->inOrderTraverse();
cout << "后序遍历：" << endl;
tree->postOrderTraverse();

tree->delNode(2, NULL);
tree->preOrderTraverse();
return 0;
}

PS：其实可以不用编写tree类的，使用node足够实现二叉树的所有操作，大家也可以试试只用node类创建一棵树，加上tree类之后会便利理解逻辑关系，各有利弊。

参考：http://www.imooc.com/video/12138