C ++中的二叉搜索树问题

Question

我正在创建一个二叉搜索树，这是我的TreeDB.cpp文件的代码：

TreeDB::TreeDB()
{
    root = NULL;
}

bool TreeDB::insert(DBentry * _entry)
{
    if (root == NULL)
    {
        root = new TreeNode(_entry);
        root->setLeft(NULL);
        root->setRight(NULL);
        cout <<"Inserted at root";
    }
    else
    {
        insert_helper(root,_entry);
    }
}

bool TreeDB::insert_helper(TreeNode *curr, DBentry * _entry)
{
 string temp1 = curr->getEntry()->getName();
 string temp2 = _entry-> getName();

 if(temp1 == temp2)
 {
     cout <<"Error: entry already exists"<<endl;
     delete _entry;
     return false;
 }

 else if(temp1<temp2)
 {
     if(curr->getRight() == NULL)
     {

         curr->setRight(new TreeNode(_entry));
         cout << "Set right";
         return true;
     }
     else
     {
         insert_helper(curr->getRight(),_entry);
     }
 }
 else
 {
     if(curr->getLeft() == NULL)
     {
         curr->setLeft(new TreeNode(_entry));
         cout <<"Set Left";
         return true;
     }
     else
     {
         insert_helper(curr->getLeft(),_entry);
     }
 }
}

我的头文件是Tree.h：

class TreeDB {

private:
   TreeNode* root;
   int probesCount;


public:

TreeDB();

~TreeDB();
bool insert(DBentry* newEntry); 
bool insert_helper(TreeNode*curr,DBentry*_entry);


};

我也在这样创建这个树的对象：

TreeDB Tree;
while (!lineStream.eof())
{
    if (command == "insert")
    {
        unsigned int address;
        string name;
        bool active;
        lineStream >> name >> address >> active;
        DBentry * a = new DBentry(name,address,active);
        Tree.insert(a);
    }

但是，每次我尝试插入某些东西时，它总是在根处插入，因此前一个永远不会被保存或者在每次插入后被删除。关于如何解决这个问题的任何提示？