//function display() prints out the contents of a binary
//search tree that stores characters in lexicographical order.
#include "tree.h"
//this functions uses recursion to display the contents of the tree
void display(Node *root)
{
   if( root != NULL)
   {
      display(root -> left);
      printf(" %c ,", root -> value);
      display(root -> right);
   }
}