PHP Access Modfiers

In PHP, access modifiers define the visibility of properties and methods of a class. The three main access modifiers are:

1. public
2. protected
3. private

Let's explore each of these with examples.

Public

A property or method declared as public can be accessed from anywhere, both inside and outside the class.

class MyClass {
    public $publicVar = "I am public";

    public function publicMethod() {
        return "This is a public method.";
    }
}

$obj = new MyClass();
echo $obj->publicVar;  // Output: I am public
echo $obj->publicMethod();  // Output: This is a public method.

Protected

A property or method declared as protected can only be accessed within the class itself and by inheriting classes.

class MyClass {
    protected $protectedVar = "I am protected";

    protected function protectedMethod() {
        return "This is a protected method.";
    }
}

class MyChildClass extends MyClass {
    public function accessProtected() {
        return $this->protectedVar . " " . $this->protectedMethod();
    }
}

$obj = new MyChildClass();
echo $obj->accessProtected();  // Output: I am protected This is a protected method.

// The following will cause an error:
// echo $obj->protectedVar;  // Fatal error: Uncaught Error: Cannot access protected property MyClass::$protectedVar
// echo $obj->protectedMethod();  // Fatal error: Uncaught Error: Call to protected method MyClass::protectedMethod()

Private

A property or method declared as private can only be accessed within the class itself. It is not accessible outside the class or by inheriting classes.

class MyClass {
    private $privateVar = "I am private";

    private function privateMethod() {
        return "This is a private method.";
    }

    public function accessPrivate() {
        return $this->privateVar . " " . $this->privateMethod();
    }
}

$obj = new MyClass();
echo $obj->accessPrivate();  // Output: I am private This is a private method.

// The following will cause an error:
// echo $obj->privateVar;  // Fatal error: Uncaught Error: Cannot access private property MyClass::$privateVar
// echo $obj->privateMethod();  // Fatal error: Uncaught Error: Call to private method MyClass::privateMethod()

Summary

• public: Accessible from anywhere.
• protected: Accessible within the class and by inheriting classes.
• private: Accessible only within the class itself.

These access modifiers help in encapsulating data and methods, providing control over the visibility and accessibility of class members.