#include <iostream>
#include <string>  

struct StringTree
{ string data;   
  StringTree * left, * right;
  StringTree(string s): data(s), left(NULL), right(NULL) { } };
  
StringTree * insert(StringTree * t, string s)
{ if (t==NULL)
    t = new StringTree(s);
  else if (s <= t->data)  
    t->left = insert(t->left, s);
  else
    t->right = insert(t->right, s);
  return t; }
  
bool find(StringTree * t, string s)
{ string ans;
  if (t==NULL)
    return 0; 
  else if (s == t->data)
    return 1;
  else if (s < t->data)
    return find(t->left, s);
  else
    return find(t->right, s); }
    
void print(StringTree * t)
{ if (t==NULL)
    return;   
  print(t->left);
  cout << t->data << endl;
  print(t->right); }
  
void main(void)
{ cout << "enter:\n";
  cout << "  i word   to insert word\n";
  cout << "  f word   to find word\n";  
  cout << "  p        to print all\n";  
  cout << "  x        to exit\n";
  StringTree * tree = NULL;
  while (1)
  { cout << "> ";
    string command;
    cin >> command;
    if (command=="i")
    { string operand;
      cin >> operand;
      tree = insert(tree, operand);
      cout << operand << " inserted\n"; }
    else if (command=="f")
    { string operand;
      cin >> operand;
      int found = find(tree, operand);
      cout << operand << ( found ? " present" : " not found" ) << "\n"; }
    else if (command=="p")
    { print(tree); }
    else if (command=="x")
    { break; }
    else
    { cout << "Get it right.\n"; } } }