关于C Primer Plus第5版的二叉树的问题

Question

//从树中删除一个项目
bool DeleteItem(const Item *pi,Tree *ptree)
{
Pair look;
look = SeekItem( pi, ptree);
//如果要删除的项目本身不存在
if(look.child == NULL)
{
return false;
}

//删除根项目
if(look.child == ptree->root)
{
    DeleteNode(&ptree->root);
}
else if(look.parent->left == look.child)
    //DeleteNode(&look.parent->left);
    DeleteNode(&(look.child));
else
    //DeleteNode(&look.parent->right);
    DeleteNode(&(look.child));
ptree->size--;
return true;

}

    DeleteNode(&look.parent->left);
    DeleteNode(&(look.child));删不干净，这是为什么

Answer 1

typedef struct pair
{
Node *parent;
Node *child;
}Pair;

static Pair SeekItem(const Item *pi,const Tree *ptree)
{
Pair look;
look.parent = NULL;
look.child = ptree->root;

if(look.child == NULL)
    return look;


while(look.child != NULL)
{
    if(ToLeft(pi, &(look.child->item)))
    {
        look.parent = look.child;
        look.child = look.child->left;
    }
    else if(ToRight(pi, &(look.child->item)))
    {
        look.parent = look.child;
        look.child = look.child->right;
    }
    else
    {
        //不在左子树，也不在右子树，即找到指定节点
        break;
    }
}

return look;

}