@Override
    public String getColumnName(int c) {
        String result;
        switch (c) {
            case 0:
                result = "Name";
                break;
            case 1:
                result = "Registration date";
                break;
            case 2:
                result = "Last log-in date";
                break;
            case 3:
                result = "Id";
                break;
            default:
                result = "Other column";
                break;
        }
        return result;
    }