custom widget code template with comments - important

<?php
error_reporting(E_ALL);
/*
Plugin Name: Custom Widget
Plugin URI: http://wpguru.in
Description: Custom Widget..
Author: Rakesh Raja
Version: 1.6
Author URI: http://wpguru.in
*/

/*main widget class starts here*/
class wpg_textwidget extends WP_Widget {


/*construct widget /display it */
    function __construct()
    {
        $params = array(
        'description' => 'Simple Text Widget',
        'name' => 'WPG Text Widget'
        );

        parent:: __construct('wpg_textwidget', '', $params);
    } /* construct of widget ends here */

    /*widget form starts here*/
    public function form($instance)
    {
        extract($instance);

         ?>

            <p>
            <label for="<?php echo $this->get_field_id( 'title' ); ?>"> Title: </label>
            <input  type="text" class="widefat"
                id="<?php echo $this->get_field_id( 'title' ); ?>"
                name="<?php echo $this->get_field_name( 'title' ); ?>"
                value="<?php if( isset($title) ) echo esc_attr($title); ?>"  />

            <label for="<?php echo $this->get_field_id( 'info' ); ?>"> Info: </label>
            <textarea  class="widefat"
                id="<?php echo $this->get_field_id( 'info' ); ?>"
                name="<?php echo $this->get_field_name( 'info' ); ?>" ><?php if( isset($info) ) echo esc_attr($info); ?>
            </textarea>

<?php
    } /*  widget form ends here */
    /* this print widget on theme page */
    public function widget($args, $instance)
    {
        extract($args);
        extract($instance);

        echo $before_widget;
            echo $before_title . $title . $after_title;
            echo $info;
        echo $after_widget;

    }/* print widget ends here */


} /*end if main widget class*/

add_action('widgets_init', 'wpg_register_wpgtextwidget');
function wpg_register_wpgtextwidget()
{
register_widget('wpg_textwidget');
}
?>