...
struct StringTreeNode
{ string data;
  StringTreeNode * left, * right;
  StringTreeNode(string s): data(s), left(NULL), right(NULL) { } };

void insert(StringTreeNode * & t, string s)
{ if (t==NULL)
    t = new StringTreeNode(s);
  else if (s <= t->data)
    insert(t->left, s);
  else
    insert(t->right, s); }

bool find(StringTreeNode * 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(StringTreeNode * t)
{ if (t==NULL)
    return;
  print(t->left);
  cout << t->data << endl;
  print(t->right); }

struct StringTree
{ StringTreeNode * it;
  StringTree(void) { it=NULL; }
  bool isempty(void) { return it!=NULL; }
  void insert(string s) { insert(it, s); }
  bool find(string s) { return find(it, s); }
  void print(void) { print(it); } };

void main(void)
{ cout << "enter: ...etc...\n";
  StringTree tree;
  while (1)
  { cout << "> ";
    string command;
    cin >> command;
    if (command=="i")
    { string operand;
      cin >> operand;
      tree.insert(operand);
      cout << operand << " inserted\n"; }
    else if (command=="f")
    { string operand;
      cin >> operand;
      int found = tree.find(operand);
      cout << operand << ( found ? " present" : " not found" ) << "\n"; }
    else if (command=="p")
    { tree.print(); }
... etc etc