1.首先是如何创建一个二叉查找树

2.再对二叉查找树进转换

代码如下：

// BSTreeNode1.cpp : 定义控制台应用程序的入口点。
//

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

struct BSTreeNode
{
int m_nValue; // value of node
BSTreeNode *m_pLeft; // left child of node
BSTreeNode *m_pRight; // right child of node
};

typedef BSTreeNode DoubleList;
DoubleList * pHead;
DoubleList * pListIndex;

void convertToDoubleList(BSTreeNode * pCurrent);
// 创建二元查找树
void addBSTreeNode(BSTreeNode * & pCurrent, int value)
{
if (NULL == pCurrent)
{
BSTreeNode * pBSTree = new BSTreeNode();
pBSTree->m_pLeft = NULL;
pBSTree->m_pRight = NULL;
pBSTree->m_nValue = value;
pCurrent = pBSTree;

}
else
{
if ((pCurrent->m_nValue) > value)
{
addBSTreeNode(pCurrent->m_pLeft, value);
}
else if ((pCurrent->m_nValue) < value)
{
addBSTreeNode(pCurrent->m_pRight, value);
}
else
{
//cout<<"重复加入节点"<<endl;
}
}
}

// 遍历二元查找树 中序
void ergodicBSTree(BSTreeNode * pCurrent)
{
if (NULL == pCurrent)
{
return;
}
if (NULL != pCurrent->m_pLeft)
{
ergodicBSTree(pCurrent->m_pLeft);
}

// 节点接到链表尾部
convertToDoubleList(pCurrent);
// 右子树为空
if (NULL != pCurrent->m_pRight)
{
ergodicBSTree(pCurrent->m_pRight);
}
}

// 二叉树转换成list
void convertToDoubleList(BSTreeNode * pCurrent)
{

pCurrent->m_pLeft = pListIndex;
if (NULL != pListIndex)
{
pListIndex->m_pRight = pCurrent;
}
else
{
pHead = pCurrent;
}
pListIndex = pCurrent;
cout<<pCurrent->m_nValue<<endl;
}

int main()
{
BSTreeNode * pRoot = NULL;
pListIndex = NULL;
pHead = NULL;
addBSTreeNode(pRoot, 10);
addBSTreeNode(pRoot, 4);
addBSTreeNode(pRoot, 3);
addBSTreeNode(pRoot, 8);
addBSTreeNode(pRoot, 12);
addBSTreeNode(pRoot, 14);
addBSTreeNode(pRoot, 15);
addBSTreeNode(pRoot, 16);
ergodicBSTree(pRoot);

system("pause");
return 0;
}

// BSTreeNode1.cpp : 定义控制台应用程序的入口点。
//

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

struct BSTreeNode
{
    int m_nValue; // value of node
    BSTreeNode *m_pLeft; // left child of node
    BSTreeNode *m_pRight; // right child of node
};

typedef BSTreeNode DoubleList;
DoubleList * pHead;
DoubleList * pListIndex;

void convertToDoubleList(BSTreeNode * pCurrent);
// 创建二元查找树
void addBSTreeNode(BSTreeNode * & pCurrent, int value)
{
    if (NULL == pCurrent)
    {
        BSTreeNode * pBSTree = new BSTreeNode();
        pBSTree->m_pLeft = NULL;
        pBSTree->m_pRight = NULL;
        pBSTree->m_nValue = value;
        pCurrent = pBSTree;

    }
    else 
    {
        if ((pCurrent->m_nValue) > value)
        {
            addBSTreeNode(pCurrent->m_pLeft, value);
        }
        else if ((pCurrent->m_nValue) < value)
        {
            addBSTreeNode(pCurrent->m_pRight, value);
        }
        else
        {
            //cout<<"重复加入节点"<<endl;
        }
    }
}

// 遍历二元查找树  中序
void ergodicBSTree(BSTreeNode * pCurrent)
{
    if (NULL == pCurrent)
    {       
        return;
    }
    if (NULL != pCurrent->m_pLeft)
    {
        ergodicBSTree(pCurrent->m_pLeft);   
    }

    // 节点接到链表尾部
    convertToDoubleList(pCurrent);
    // 右子树为空
    if (NULL != pCurrent->m_pRight)
    {
        ergodicBSTree(pCurrent->m_pRight);
    }
}

// 二叉树转换成list
void  convertToDoubleList(BSTreeNode * pCurrent)
{

    pCurrent->m_pLeft = pListIndex;
    if (NULL != pListIndex)
    {
        pListIndex->m_pRight = pCurrent;
    }
    else
    {
        pHead = pCurrent;
    }   
    pListIndex = pCurrent;
    cout<<pCurrent->m_nValue<<endl;
}

int main()
{
    BSTreeNode * pRoot = NULL;
    pListIndex = NULL;
    pHead = NULL;
    addBSTreeNode(pRoot, 10);
    addBSTreeNode(pRoot, 4);
    addBSTreeNode(pRoot, 3);
    addBSTreeNode(pRoot, 8);
    addBSTreeNode(pRoot, 12);
    addBSTreeNode(pRoot, 14);
    addBSTreeNode(pRoot, 15);
    addBSTreeNode(pRoot, 16);
    ergodicBSTree(pRoot);

	system("pause");
    return 0;
}

结果：