把二元查找树转变成排序的双向链表

#include <iostream.h>

struct BSTreeNode
{
    int m_nValue;
    struct BSTreeNode *m_pLeft;
    struct BSTreeNode *m_pRight;
};

void addBSTreeNode(BSTreeNode *&pCurrent,int value); //建立二叉排序树
void inOrderBSTree(BSTreeNode *pBSTree); //中序遍历
void convertToDoubleList(BSTreeNode *pCurrent);//转换成双链表

BSTreeNode *pHead=NULL;//指向双链表的头结点
BSTreeNode *pIndex=NULL;//指向前一个结点

int main()
{
    BSTreeNode *pRoot=NULL;
    addBSTreeNode(pRoot,10);
    addBSTreeNode(pRoot,6);
    addBSTreeNode(pRoot,14);
    addBSTreeNode(pRoot,4);
    addBSTreeNode(pRoot,8);
    addBSTreeNode(pRoot,12);
    addBSTreeNode(pRoot,16);

    inOrderBSTree(pRoot);
    return 0;
}


void addBSTreeNode(BSTreeNode *&pCurrent,int value)
{
    if(pCurrent==NULL)
    {
        BSTreeNode *pBSTree=new BSTreeNode;
        pBSTree->m_nValue=value;
        pBSTree->m_pLeft=NULL;
        pBSTree->m_pRight=NULL;
        pCurrent=pBSTree;
    }
    else if (pCurrent->m_nValue<value)
    {
        addBSTreeNode(pCurrent->m_pRight,value);
    }
    else if (pCurrent->m_nValue>value)
    {
        addBSTreeNode(pCurrent->m_pLeft,value);
    }
    else
    {
        cout<<"node repeated"<<endl;
    }
}

void inOrderBSTree(BSTreeNode *pBSTree)
{
    if (NULL==pBSTree)
    {
        return;
    }

    if (NULL!=pBSTree->m_pLeft)
    {
        inOrderBSTree(pBSTree->m_pLeft);
    }

    convertToDoubleList(pBSTree);

    if (NULL!=pBSTree->m_pRight)
    {
        inOrderBSTree(pBSTree->m_pRight);
    }
}


void convertToDoubleList(BSTreeNode *pCurrent)
{
    pCurrent->m_pLeft=pIndex;

    if (NULL==pIndex)
    {
        pHead=pIndex;
    }

    else
    {
        pIndex->m_pRight=pCurrent;
    }

    pIndex=pCurrent;

    cout<<pCurrent->m_nValue<<" ";
}