class 상속과 생성자

자식 클래스가 생성자를 정의하는 경우 부모 생성자는 암시 적으로 호출되지 않습니다. 부모 생성자를 실행 하려면 자식 생성자 내에서 parent :: __ construct ()를 호출 해야합니다. 자식이 생성자를 정의하지 않으면 일반 클래스 메서드처럼 (비공개로 선언되지 않은 경우) 부모 클래스에서 상속 될 수 있습니다.

 

<?
class ParentClass {
    function __construct() {
        echo "In ParentClass constructor<br>";
    }
}

class ChildClass extends ParentClass {
    function __construct() {
        parent::__construct();
        echo "In ChildClass constructor<br>";
    }
}

class OtherChildClass extends ParentClass {
    // inherits ParentClass's constructor
}

// In ParentClass constructor
$obj = new ParentClass();

// In ParentClass constructor
// In ChildClass constructor
$obj = new ChildClass();

// In ParentClass constructor
$obj = new OtherChildClass();
?>