public String printSortedBookList(ArrayList<Book> b, JTextArea t) {
        // clear text area
        t.setText("");

        // set tab size
        t.setTabSize(12);
        
        // add header
        t.append("Index\tTitle\tGenre\tPrice\n");
        
        for (Book c : b) {
            output = c.getbookIndex() + "\t" + c.getbookTitle() + "\t" + c.getGenre() + "\t$" + c.getPrice() + "\n";
            t.append(output);
        }
        return output;
    }