二叉树C++ Version

#include <iostream.h>
#include <cstring>

typedef int KeyType;
#define NUM 11
class BinStree;
class BinSTreeNode
{
public:
    KeyType key;
    BinSTreeNode *lchild;
    BinSTreeNode *rchild;
    BinSTreeNode()
    {
        lchild = NULL;
        rchild = NULL;
    }
};

class BinSTree
{
public:
    BinSTreeNode *root;
    BinSTree()
    {
        root = NULL;
    }
    ~BinSTree()
    {
        //delete root;
    }
    BinSTreeNode *BSTreeSearch( BinSTreeNode *bt, KeyType k, BinSTreeNode *&p );
    void BSTreeInsert( BinSTreeNode *&bt, KeyType k );
    int BSTreeDelete( BinSTreeNode *&bt, KeyType k );
    void BSTreePreOrder(BinSTreeNode *bt);
    bool IsEmpty()
    {
        return root == NULL;
    }
};

/**
  *  二叉树排序查找算法
  *  在根指针为bt的二叉排序树中查找元素k的节点，若查找成功，则返回指向该节点的指针
  *  参数p指向查找到的结点，否则返回空指针，参数p指向k应插入的父结点
  */
BinSTreeNode* BinSTree::BSTreeSearch( BinSTreeNode *bt, KeyType k, BinSTreeNode *&p )
{
    BinSTreeNode *q = NULL;
    q = bt;
    while(q)
    {
        p = q;
        if( q->key == k )
        {
            return(p);
        }
        if( q->key > k )
            q = q->lchild;
        else
            q = q->rchild;
    }
    return NULL;
}

/**
  *  二叉排序树的插入节点算法
  *  bt指向二叉排序树的根结点，插入元素k的结点
  */
void BinSTree::BSTreeInsert( BinSTreeNode *&bt, KeyType k )
{
    BinSTreeNode *p = NULL, *q;
    q = bt;
    if( BSTreeSearch( q, k, p ) == NULL )
    {
        BinSTreeNode *r = new BinSTreeNode;
        r->key = k;
        r->lchild = r->rchild = NULL;
        if( q == NULL )//这里的q代表的bt，不是search函数里面的q
        {
            bt = r;         //被插入节点做为树的根节点
        }
        if( p && k < p->key )
            p->lchild = r;
        else if( p )
            p->rchild = r;
    }
}
/**
 * 中序遍历 
 */ 
void BinSTree::BSTreePreOrder(BinSTreeNode *bt)
{
    if(bt != NULL)
    {
        cout << bt->key << " ";
        BSTreePreOrder(bt->lchild);
        BSTreePreOrder(bt->rchild);
    }
}
/**
  * 二叉排序树的删除结点算法
  * 在二叉排序树中删除元素为k的结点，*bt指向二叉排序树的根节点
  * 删除成功返回1，不成功返回0.
  */
int BinSTree::BSTreeDelete( BinSTreeNode *&bt, KeyType k )
{
    BinSTreeNode *f, *p, *q, *s;
    p = bt;
    f = NULL;
    //查找关键字为k的结点，同时将此结点的双亲找出来
    while( p && p->key != k )
    {
        f = p;
        if( p->key > k )
            p = p->lchild;
        else
            p = p->rchild;
    }
    if( p == NULL )   //找不到待删除的结点时返回
        return 0;
    if( p->lchild == NULL )  //待删除结点的左子树为空
    {
        if( f == NULL )  //待删除结点为根节点
            bt = p->rchild;
        else if( f->lchild == p )  //待删结点是其双亲结点的左节点
            f->lchild = p->rchild;
        else
            f->rchild = p->rchild;  //待删结点是其双亲结点的右节点
        delete p;
    }
    else                    //待删除结点有左子树
    {
        q = p;
        s = p->lchild;
        while( s->rchild )  //在待删除结点的左子树中查找最右下结点
        {
            q = s;
            s = s->rchild;
        }
        if( q == p )
            q->lchild = s->lchild;
        else
            q->rchild = s->lchild;

        p->key = s->key;
        delete s;
    }
    return 1;
}
int main( void )
{
    int a[NUM] = { 34, 18, 76, 13, 52, 82, 16, 67, 58, 73, 72 };
    int i;
    BinSTree bst;
    BinSTreeNode *pBt = NULL, *p = NULL, *pT = NULL;

    for( i = 0; i < NUM; i++ )
    {
        bst.BSTreeInsert( pBt, a[i] ); //创建二叉排序树
    }
    pT = bst.BSTreeSearch( pBt, 52, p ); //搜索排序二叉树
    bst.BSTreePreOrder(pBt);
    cout << endl;
    bst.BSTreeDelete( pBt, 13 );   //删除无左孩子的情况
    bst.BSTreePreOrder(pBt);
    cout << endl;
    bst.BSTreeDelete( pBt, 76 );   //删除有左孩子的情况
    bst.BSTreePreOrder(pBt);
    cout << endl;
    return 0;
}

注意:? *& bt 和 *bt 和&bt的不同。