// 把二叉树转换成双向链表.struct BinaryTreeNode{    int m_nValue;    BinaryTreeNode *m_pLeft;    BinaryTreeNode *m_pRight;public:    BinaryTreeNode(int v):m_nValue(v),m_pLeft(NULL),m_pRight(NULL){}};void Convert(BinaryTreeNode *t,BinaryTreeNode **head,BinaryTreeNode **last){    BinaryTreeNode *lh,*ll,*rh,*rl;    if(t!=NULL)    {        Convert(t->m_pLeft,&lh,&ll);        if(ll==NULL)        {            *head=t;        }        else        {            *head=lh;            ll->m_pRight=t;            t->m_pLeft=ll;        }        Convert(t->m_pRight,&rh,&rl);        if(rh==NULL)        {            t->m_pRight=NULL;            *last=t;        }        else        {            t->m_pRight=rh;            rh->m_pLeft=t;            *last=rl;        }    }    else    {        *head=NULL;        *last=NULL;    }}    BinaryTreeNode b1(10),b21(6),b22(14),b31(4),b32(8),b33(12),b34(16);    void printMidOrder(BinaryTreeNode *t)    {        if(t)        {            printMidOrder(t->m_pLeft);            cout<
     
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       m_nValue;            printMidOrder(t->m_pRight);        }    }void main(){     b1.m_pLeft=&b21;    b1.m_pRight=&b22;    b21.m_pLeft=&b31;    b21.m_pRight=&b32;    b22.m_pLeft=&b33;    b22.m_pRight=&b34;    BinaryTreeNode *head,*last;    printMidOrder(&b1);    Convert(&b1,&head,&last);    // 输出转换结果    BinaryTreeNode *p=head;    while(p!=NULL)    {        cout<
       
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         m_nValue;        p=p->m_pRight;    }    system("pause");}