Codeigniter Calendar Library Tutorial Update - codeigniter

Question

following along with :CodeIgniter from Scratch: The Calendar Library
The code from the earlier version:
class Mycal extends CI_Controller
{
function display($month, $year) {
$conf = array(
'start_day' => 'Monday',
'show_next_prev' => true,
'next_prev_url' => base_url() . 'mycal/display'
);
$this->load->library('calendar', $conf);
print $this->calendar->generate($month, $year);
}
}
generates these errors:
A PHP Error was encountered
Severity: Warning
Message: Missing argument 1 for Mycal::display()
Filename: controllers/mycal.php
Line Number: 4 A PHP Error was encountered
Severity: Warning
Message: Missing argument 2 for Mycal::display()
Filename: controllers/mycal.php
Line Number: 4 A PHP Error was encountered
Severity: Notice
Message: Undefined variable: year
Filename: controllers/mycal.php
Line Number: 16 A PHP Error was encountered
Severity: Notice
Message: Undefined variable: month
Filename: controllers/mycal.php
Line Number: 16
I updated to the following:
class Mycal extends CI_Controller {
function display($year = null, $month = null) {
$year = $this->uri->segment(3);
$month = $this->uri->segment(4);
$conf = array(
'start_day' => 'Monday',
'show_next_prev' => true,
'next_prev_url' => base_url() . 'mycal/display/'
);
$this->load->library('calendar', $conf);
print $this->calendar->generate($year, $month);
}
}
It works as desired, but is it following best practices for CI?

Answer 1

When the display function is called, $year and $month will be set to the URI segments (or null) for you. The $this->uri->segment call is not needed here.
Also echo is slightly faster than print (according to this).
function display($year = null, $month = null) {
$conf = array(
'start_day' => 'Monday',
'show_next_prev' => true,
'next_prev_url' => base_url() . 'mycal/display/'
);
$this->load->library('calendar', $conf);
echo $this->calendar->generate($year, $month);
}

Answer 2

Building off of Rocket's answer, you need to set the year and month if they're not passed in the url.
By doing $year = null, $month = null as the parameters, it means that if no parameters are passed, $year will equal null and $month will equal null, but if parameters are passed in the url, $year will equal the first parameter and $month will equal the next parameter.
function display($year = null, $month = null) {
$year = ($year == null) ? date('Y') : $year;
$month = ($month == null) ? date('n') : $month;
$conf = array(
'start_day' => 'Monday',
'show_next_prev' => true,
'next_prev_url' => base_url() . 'mycal/display/'
);
$this->load->library('calendar', $conf);
echo $this->calendar->generate($year, $month);
}