不會啊，我就是按老師的代碼敲的

/************************************************************
二叉樹（鏈表表示）
課程要求：完成二叉樹的基本操作
????1，樹的創建和銷毀
????2，樹中結點的搜索
????3，樹中結點的添加與刪除
????4，樹中結點的遍歷
????
????Tree();???//創建樹
????~Tree();???????????????//銷毀樹
????Node?*SearchNode(Tree?*pTree,int?nodeindex);??//根據索引尋找結點?
????bool?AddNode(Tree?*pTree,int?nodeindex,int?direction,Node?*pNode);??//添加結點
????bool?DeleteNode(Tree?*pTree,int?nodeindex,Node?*pNode);????????????//刪除結點
????void?preorderTraverse();???????????????//先序遍歷二叉樹
????void?InorderTraverse();???????????????//中序遍歷二叉樹
????void?PosorderTraverse();???????????????//后序遍歷二叉樹

結點要素：索引、數據、左孩子指針、右孩子指針、父結點指針?
????
????????????3(0)
????????????
?????5(1)??????????8(2)
?????
2(3)?????6(4)???9(5)???7(6)
????
那個direction是“0”時表示插入到左孩子，是“1”時表示插入到右孩子?
先序遍歷結果（根----左----右）0?1?3?4?2?5?6??
中序遍歷結果（左----根----右）3?1?4?0?5?2?6????
后序遍歷結果（左----右----根）3?4?1?5?6?2?0

*************************************************************/

#include<iostream>
#include<stdio.h>

using?namespace?std;

class?Node
{
public:
????Node();//構造函數?
????Node?*SearchNode(int?nodeindex);
????void?DeleteNode();
????void?preorderTraverse();???????????????//先序遍歷二叉樹
????void?InorderTraverse();???????????????//中序遍歷二叉樹
????void?PosorderTraverse();???????????????//后序遍歷二叉樹
????int?index;
????int?data;
????Node?*pLChild;
????Node?*pRChild;
????Node?*pParent;????
};

class?Tree
{
public:
????Tree();????????????????????????????????//創建樹?
????~Tree();???????????????????????????????//銷毀樹?
????Node?*SearchNode(int?nodeindex);???????//搜索結點?
????bool?AddNode(int?nodeindex,int?direction,Node?*pNode);???//添加結點?
????bool?DeleteNode(int?nodeindex,Node?*pNode);??????????????//刪除結點?
????void?preorderTraverse();???????????????//先序遍歷二叉樹
????void?InorderTraverse();???????????????//中序遍歷二叉樹
????void?PosorderTraverse();???????????????//后序遍歷二叉樹
private:
????Node?*m_pRoot;???
};

Node::Node()
{
????index=0;
????data=0;
????pLChild=NULL;
????pRChild=NULL;
????pParent=NULL;????
}?

Tree::Tree()
{
????m_pRoot=new?Node();
}

Tree::~Tree()
{
????//DeleteNode(0,NULL);//方法一?
????m_pRoot->DeleteNode();//方法二?
}

Node?*Node::SearchNode(int?nodeindex)
{
????if(this->index==nodeindex)
????????return?this;
????Node?*temp=NULL;
????if(this->pLChild!=NULL)
????{
????????if(this->pLChild->index==nodeindex)
????????????return?this->pLChild;
????????else
????????????temp=this->pLChild->SearchNode(nodeindex);
????????
????}
????if(this->pRChild!=NULL)
????{
????????if(this->pRChild->index==nodeindex)
????????????return?this->pRChild;
????????else
????????????temp=this->pRChild->SearchNode(nodeindex);
????????if(temp!=NULL)
????????????return?temp;
????}
????return?NULL;
}

Node?*Tree::SearchNode(int?nodeindex)
{
????return?m_pRoot->SearchNode(nodeindex);
}

bool?Tree::AddNode(int?nodeindex,int?direction,Node?*pNode)
{
????Node?*temp=SearchNode(nodeindex);
????if(temp==NULL)
????????return?false;
????Node?*node=new?Node();
????if(node==NULL)
????????return?false;
????node->index=pNode->index;
????node->data=pNode->data;
????
????node->pParent=temp;
????if(direction==0)
????????temp->pLChild=node;
????if(direction==1)
????????temp->pRChild=node;
????return?true;
}

bool?Tree::DeleteNode(int?nodeindex,Node?*pNode)
{
????Node?*temp=SearchNode(nodeindex);
????if(temp==NULL)
????????return?false;
????if(pNode!=NULL)
????{
????????pNode->data=temp->data;
????}
????temp->DeleteNode();
????return?true;
}

void?Node::DeleteNode()
{
????if(this->pLChild!=NULL)
????????this->pLChild->DeleteNode();
????if(this->pRChild!=NULL)
????????this->pRChild->DeleteNode();
????if(this->pParent!=NULL)
????{
????????if(this->pParent->pLChild==this)
????????????this->pParent->pLChild=NULL;
????????if(this->pParent->pRChild==this)
????????????this->pParent->pRChild=NULL;
????}
????delete?this;
}

void?Node::preorderTraverse()
{
????cout?<<?this->index?<<?"???"?<<?this->data?<<?endl;
????if(this->pLChild!=NULL)
????????this->pLChild->preorderTraverse();
????if(this->pRChild!=NULL)
????????this->pRChild->preorderTraverse();
}?

void?Node::InorderTraverse()
{
????if(this->pLChild!=NULL)
????????this->pLChild->InorderTraverse();
????????
????cout?<<?this->index?<<?"???"?<<?this->data?<<?endl;
????
????if(this->pRChild!=NULL)
????????this->pRChild->InorderTraverse();
}
void?Node::PosorderTraverse()
{
????if(this->pLChild!=NULL)
????????this->pLChild->PosorderTraverse();
????
????if(this->pRChild!=NULL)
????????this->pRChild->PosorderTraverse();
????????
????cout?<<?this->index?<<?"???"?<<?this->data?<<?endl;
}

void?Tree::preorderTraverse()
{
????m_pRoot->preorderTraverse();
}?

void?Tree::InorderTraverse()
{
????m_pRoot->InorderTraverse();
}?

void?Tree::PosorderTraverse()
{
????m_pRoot->PosorderTraverse();
}?

int?main()
{
????Node?*node1=new?Node();
????node1->index=1;
????node1->data=5;
????
????Node?*node2=new?Node();
????node2->index=2;
????node2->data=8;
????
????Node?*node3=new?Node();
????node3->index=3;
????node3->data=2;
????
????Node?*node4=new?Node();
????node4->index=4;
????node4->data=6;
????
????Node?*node5=new?Node();
????node5->index=5;
????node5->data=9;
????
????Node?*node6=new?Node();
????node6->index=6;
????node6->data=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);
????
????//printf("刪除最后一個結點：\n");
????//tree->DeleteNode(6,NULL);
????
????printf("刪除中間某個結點：\n");
????tree->DeleteNode(2,NULL);
//????printf("前序遍歷的結果：\n");
//????tree->preorderTraverse();
????
//????printf("中序遍歷的結果：\n");
//????tree->InorderTraverse();?
????
????printf("后序遍歷的結果：\n");
????tree->PosorderTraverse();?
????delete?tree;
????return?0;
}