text: #ifndef _TREE_H_INCLUDED_
  #define _TREE_H_INCLUDED_
  #include <stdbool.h>
  #define MAX_PET_NAME 20
  #define MAX_PET_KIND 20
  
  #define MAXITEMS 20
  
  typedef struct item
  {
  	char petname[MAX_PET_NAME];
  	char petkind[MAX_PET_KIND];
  } Item;
  
  typedef struct trnode
  {
  	Item item;
  	struct trnode * left;
  	struct trnode * right;
  } Trnode;
  
  typedef struct tree
  {
  	Trnode * root;
  	int size;
  } Tree;
  
  void InitalizeTree(Tree * ptree);
  
  bool TreeIsEmpty(const Tree * ptree);
  
  bool TreeIsFull(const Tree * ptree);
  
  int TreeItemCount(const Tree * ptree);
  
  bool AddItem(const Item * pi, Tree * ptree);
  
  bool InTree(const Item * pi, const Tree * ptree);
  
  bool DeleteItem(const Item * pi, Tree * ptree);
  
  void Traverse(const Tree * ptree, void (*pfun)(Item item));
  
  void DeleteAll(Tree * ptree);
  
  #endif // _TREE_H_INCLUDED_
  