void oldrecursiveprint(StringTree * t)
                                    { // this is position 1;
                                      if (t!=NULL)
                                      { oldrecursiveprint(t->left);
                                        // this is position 2;
                                        cout << t->data << "\n";
                                        oldrecursiveprint(t->right); }
                                      }
...
struct LittleNote
{ StringTree * tree;
  int position;
  LittleNote(void) { }
  LittleNote(StringTree * t, int pos): tree(t), position(pos) { } };

LittleNote stack[100];
int numinstack = 0;

void push(LittleNote n)
{ stack[numinstack] = n;
  numinstack += 1; }

LittleNote pop(void)
{ numinstack -= 1;
  return stack[numinstack]; }

void print(StringTree *t)
{ numinstack = 0;
  push(LittleNote(t, 1));
  while (numinstack>0)
  { LittleNote note = pop();
    t = note.tree;
    switch (note.position)
    {
      case 1: { if (t!=NULL)
                { push(LittleNote(t, 2));
                  push(LittleNote(t->left, 1)); }
                break; }

      case 2: { cout << t->data << "\n";
                push(LittleNote(t->right, 1));
                break; }

    } }
  cout << "\n"; }
...