When creating a new object, you can pass a list of arguments to the class being called. These are passed to a special method within the class, called the constructor, which initializes various properties. This is done using the __construct() function.
The following is an example of a class with a constructor function. This is the same example as in the previous chapter, but the setting of the properties are initialized.
<?php
class People {
// These are the class properties
public $name;
public $country;
// The constructor function
function __construct($name, $country) {
$this->name = $name;
$this->country = $country;
}
// More class methods
function get_name() {
return $this->name;
}
function get_country() {
return $this->country;
}
}
// new instance of the People() class
$alex = new People('Alexander','UK');
// accessing the object properties
echo "Name: " . $alex->get_name();
echo "<br>";
echo "Country: " . $alex->get_country();
PHP Destructors
PHP also has the ability to create destructor methods. This ability is useful when code has made the last reference to an object or when a script reaches the end. This is done by creating a __destruct() function. Let's take the example above and make a destructor function.
<?php
class People {
// These are the class properties
public $name;
public $country;
// The constructor function
function __construct($name, $country) {
$this->name = $name;
$this->country = $country;
}
function __destruct() {
echo "Name: " . $this->name;
echo "<br>";
echo "Country: " . $this->country;
}
}
// new instance of the People() class
$alex = new People('Alexander','UK');
Exercise
Create a class named Car with name and year as its properties. Create the class constructor a destructor functions. The constructor sets the name and year, while the destructor prints these properties using the format : Name - Year. Create an instance of your class with the object name, $ford with its name as Ford and year as 2021.
<?php
<?php
class Car {
public $name;
public $year;
function __construct($name, $year) {
$this->name = $name;
$this->year = $year;
}
function __destruct() {
echo $this->name . " - " . $this->year;
}
}
$ford = new Car('Ford', '2021');
{
"test_output_contains":
{
"expected":"Ford - 2021",
"error_message":"Sorry, wrong output. Check your format."
},
"test_variable_exists":
[
{
"object":"$ford",
"error_message":"Have you declared <code>$ford<\/code>?"
},
{
"object":"$name",
"error_message":"Have you declared <code>$name<\/code>?"
},
{
"object":"$year",
"error_message":"Have you declared <code>$year<\/code>?"
}
],
"test_function_exists":
[
{
"object":"__construct",
"error_message":"Did you create <code>__construct<\/code>?"
},
{
"object":"__destruct",
"error_message":"Did you create <code>__destruct<\/code>?"
}
],
"success_message":"Good job!",
"error_message":"There is something wrong on your code."
}