...
int printlevel(StringTree * t, int level)
{ int numprinted=0;
  if (t==NULL)
    return numprinted;
  numprinted += printlevel(t->left, level-1);
  if (level==0)
  { cout << t->data;
    numprinted+=1; }
  else
    spaces(t->data.length());
  numprinted += printlevel(t->right, level-1);
  return numprinted; }

void print(StringTree * t)
{ for (int i=0; true; i+=1)
  { int numprinted = printlevel(t, i);
    cout << "\n\n";
    if (numprinted==0) break; } }
...
...
    else if (command=="p")
    { print(tree);
      cout << "\n"; }
...