text: typedef struct tree Tree;
  
  Tree * create();
  void destroy_tree(Tree * tree);
  void add_node(Tree * tree, char name[]);
  void remove_node(Tree * tree, char * name);
  void remove_node_biggest(Tree * tree, char * name);
  void remove_node_smallest(Tree * tree, char * name);
  int count_nodes(Tree * tree);
  int count_leaf(Tree * tree);
  int height(Tree * tree);
  int search(Tree * tree, char * name);
  void search_node(Tree * tree, char * name);
  void print_tree(Tree * tree);
  void print_substring(Tree * tree, char * substring);
  void load_file(Tree * tree);
  void save_file_in_order(Tree * tree, FILE * file);