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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 prepare(StringTree *t)
{ numinstack = 0;
  push(LittleNote(t, 1)); }

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

      case 2: { push(LittleNote(t->right, 1));
                return t->data; } } }

  return "**end**"; }

void print(StringTree *t)
{ prepare(t);
  while (1)
  { string s = getnext();
    if (s=="**end**")
      break;
    cout << s << "\n"; } }
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