Recursive object instantiation (in PHP)? - php

Question

So in my PHP program I'm creating a calendar feature and one of the classes is "CalendarDay". What I want to do is be able to instantiate a new day for each day count, so for example new CalendarDay (22) means a new 22nd of the month date. There is also a show() function used for displaying each day. The class itself functions normally but when I try instantiating new days using recursion it no longer seems to work as everything related to the instantiated object disappears from the webpage.
class CalendarDay{
private $current_month;
private $current_year;
private $current_date;
public $reminderSet;
public $reminders;
public function __construct($current_day_of_month){
$current_year = date("Y");
$current_month = date("m");
$this->days_in_month = cal_days_in_month(CAL_GREGORIAN, $current_month, $current_year);
$this->current_date = date("d");
$this->current_day_of_month = $current_day_of_month;
}
public function show(){
$output = '<div class = "generator>"';
//$output .= $this->current_date;
//$output .= '<h1>' . $this->current_date . '</h1>';
$output .= '</div>';
$output .= $this->current_day_of_month;
echo $output;
}
}
My failed attempt at recursion:
for ($countTo31 == 0; $countTo31 == 31; $countTo31++){
$holder = $countTo31;
$date = new CalendarDay ($holder);
$date->show();
}
For the reference, this original block of code without the recursion works normally:
$holder = $countTo31;
$date = new CalendarDay ($holder);
$date->show();

Answer 1

I'm very confused with what you're trying to accomplish...
You have a "day" class which takes input to initialise a specific day but instead actually works out the current day based on date("Y-m-d");?.. And then outputs the input day anyway?
Honestly, it looks more like you want a "month" object
Initial problems
You use == to define your starting point
== is not an assignment operator, it's a comparison.
It effectively adds an additional iteration of the loop at the start of the loop
for($i == 1; $i < 5; $i++){
echo $i;
}
// Loop 1:
// --> Notice on $i == 1
// --> Notice on $i < 5
// --> Notice on echo $i
// --> Notice on $i++
// Loop 2:
--> $i = 1 BECAUSE of the previous $i++
so the intended loop starts...
Additionaly the loop, in this case, should start with 1 not 0(!)
You use == to define your condition
for loops like yours work effectively as:
for ( A ; B ; C ){
// Do something...
}
// Loop works as:
// Check A against B
// If TRUE then "Do something..."
// and then do C
// IF FALSE then break
However, even if your assignment (A) was correct (i.e. $countTo31 = 1), it still wouldn't work because 1 !== 31 and therfore the loop breaks from the start
It should be $countTo31 <= 31
Looping over object, rewriting the variable
Your code currently rewrites the variable which holds the date object with every loop
Effectively you create an object to output the day, output that data, and instantly remove the object so that it can't be used for anyting else...
Your HTML output has a " in the wrong place:
$output = '<div class = "generator>"';
//Should be...
$output = '<div class = "generator">';
Some of the variables in your class are not assigned or declared properly
$current_month is declared but never assigned
$current_year is declared but never assigned
$current_day_of_month is assigned but not declared
$days_in_month is assigned but not declared
Interim solution
Without further information on what you are intending to do it isn't possible to give good/accurate guidance, so I will leave a working example which should show you what to do:
$days_in_month = cal_days_in_month(
CAL_GREGORIAN,
date("m"),
date("Y")
);
for ($day = 1; $day <= $days_in_month; $day++){
echo "Day {$day}<br>";
}
Proposed changes
It doesn't look as though you really even want a "day" class for the functions you're trying to implement. So, in my mind, it would be better to first create a "month" object with all of the days of the month and then have that generate a "day" object for each day of the month which then can gather the information for each day e.g. reminders.
Doing it this way you can then update each day as you go with, for example, user input or database data.
class Month
{
private $month;
private $year;
private $days = [];
public function __construct($month, $year)
{
$this->month = $month;
$this->year = $year;
$number_of_days = cal_days_in_month(
CAL_GREGORIAN,
$month,
$year
);
for ($i = 1; $i <= $number_of_days; $i++){
$date = "{$this->year}-{$this->month}-{$i}";
// $days[] = new Day($date);
$this->days[$i] = new Day($date);
}
}
public function getDay($day)
{
return $this->days[$day];
}
public function getNumberOfDays()
{
return count($this->days);
}
}
class Day
{
private $date;
private $reminders = [];
public function __construct($date)
{
$this->date = $date;
// Initialise day...
# Get reminders
# Get meetings
# Get bills to pay
}
public function getReminders()
{
return $this->reminders;
}
public function setReminder($content, $time)
{
// Set reminders
$this->reminders[] = [
"content" => $content,
"time" => $time
];
}
public function show()
{
return date("d / m / Y", strtotime($this->date));
}
}
$month = new Month(12, 2020);
for ($i = 1; $i <= $month->getNumberOfDays(); $i++){
echo $month->getDay($i)->show()."<br>";
}