The following code shows how to use inheritance during class definition.
<?php
class Person {
protected $firstname;
protected $surname;
public function __construct(string $firstname, string $surname) {
$this->firstname = $firstname;
$this->surname = $surname;
} //w ww . ja v a 2 s .com
public function getFirstname(): string {
return $this->firstname;
}
public function getSurname(): string {
return $this->surname;
}
}
class Customer extends Person {
private static $lastId = 0;
private $id;
private $email;
public function __construct(
int $id,
string $name,
string $surname,
string $email
) {
if (empty($id)) {
$this->id = ++self::$lastId;
} else {
$this->id = $id;
if ($id > self::$lastId) {
self::$lastId = $id;
}
}
$this->name = $name;
$this->surname = $surname;
$this->email = $email;
}
public static function getLastId(): int {
return self::$lastId;
}
public function getId(): int {
return $this->id;
}
public function getEmail(): string {
return $this->email;
}
public function setEmail($email): string {
$this->email = $email;
}
}
?>
The keyword extends tells PHP that this class is a child of the Person class.
To reference the parent's implementation, use the keyword parent:: instead of $this.
public function __construct( int $id, string $firstname, string $surname, string $email ) { parent::__construct($firstname, $surname); if (empty($id)) { $this->id = ++self::$lastId; } else { $this->id = $id; if ($id > self::$lastId) { self::$lastId = $id; } } $this->email = $email; }