Please Please help me! Someone help me understand how a C++ sorting numbers driver program can have a class member functions void insert(double x);

Please Please help me! Someone help me understand how a C++ sorting numbers driver program can have a class member functions void insert(double x); bool search(double x); void inorder(vector <double> & v), the simple binary search tree search function will call a private recursive member function bool search(double x, BtreeNode *t) Inorder function is empty vector v: then fills v with inorder list of numbers stored in binary search tree.