private questionNode create(questionNode previous, questionNode current) {	//recursive tree building method
		try {
			if(!fReader.hasNextLine())
				return null;
			if(fReader.nextLine().equals("Q:")) {	//creates new questionNode for a question and it's children
				current = new questionNode(fReader.nextLine(), previous);
				current.yes = create(current, current.yes);
				current.no = create(current, current.no);
				return current;
			} else {	//questionNode for an Answer
				return new questionNode(fReader.nextLine(), previous);
			}
		}
		catch(NoSuchElementException e) {	//if there is no next line, returns null
			return null;
		}
	}