if ((_sp < 0) || (_node < _stack[_sp])) return(_node);
if ((_sp < 0) || (_node < _stack[_sp])) return returnNode(_node);
	public int next() {	    // Advance node index and check if all nodes have been returned.	    while (++_node < _startNode) {		// Check if we reached one of the base node's ancestors		if ((_sp < 0) || (_node < _stack[_sp])) return(_node);		// Anvance past the next ancestor node		_sp--;	    }	    return(NULL);	}