//  File: bstree.h
//
//  A binary search tree class

// The following declaration tell the compiler that the symbol
// "BSTreeNode" is a class, before we fully define the class.
// This allows us to use pointers to BSTreeNode in BSTree.
// Think of it as a class "prototype".

class BSTreeNode ;


// Simple example of "extra" data stored in a node
//
typedef char data ;



class BSTree {

public:
   BSTree() ;
   ~BSTree() ;

   void Inorder() ;

   void Insert(int) ;
   void Insert(int, data) ;

   BSTree *Search(int) ;    // Find node with given key
   void RemoveRoot() ;      // Remove root of the subtree

   BSTree *Min() ;          // Find node with smallest key
   BSTree *Max() ;          // Find node with largest key

   int IsEmpty() ;          // 1 if empty, 0 otherwise
   int RootKey() ;          // Do stuff with root of tree,
   data *RootDataPtr() ;    //   requires non-empty tree
   void RootPrint() ;

protected:
   BSTreeNode *root ;           // pointer to root BSTreeNode
   BSTreeNode *ExtractMin() ;   // remove and return node with min key
   BSTreeNode *ExtractRoot() ;  // remove and return root node
} ;



class BSTreeNode {

friend class BSTree ;

public:
   data stuff ;         // stuff other than key in the tree
   void Print() ;       // Can have other member functions.

protected:
   int key ;            // ordering in tree is based on key

   BSTreeNode() ;       // Constructors
   BSTreeNode(int) ;
   BSTreeNode(int, data) ;

   ~BSTreeNode() ;      // protected destructor

   BSTree left ;        // left subtree
   BSTree right ;       // right subtree
} ;