PHP Access Modifiers

Intermediate~25 min read

Access modifiers control who can access properties and methods. They're essential for encapsulation - hiding internal details and exposing only what's necessary!

<?php
// Access Modifiers

class BankAccount
{
    public $accountNumber;      // Accessible everywhere
    protected $balance;         // Accessible in class and subclasses
    private $pin;              // Only accessible in this class

public function __construct($accountNumber, $balance, $pin)
    {
        $this->accountNumber = $accountNumber;
        $this->balance = $balance;
        $this->pin = $pin;
    }

// Public method - accessible everywhere
    public function getBalance()
    {
        return $this->balance;
    }

// Public method to deposit
    public function deposit($amount)
    {
        $this->balance += $amount;
    }

// Private method - only within this class
    private function validatePin($pin)
    {
        return $this->pin === $pin;
    }
}

$account = new BankAccount("123456", 1000, "1234");
echo $account->accountNumber . "\n";  // OK - public
echo $account->getBalance() . "\n";   // OK - public method
// echo $account->balance;  // Error - protected
// echo $account->pin;      // Error - private

Output

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PHP Access Modifiers - public, protected, private

Three Access Levels

Modifier	Class	Subclass	Outside
`public`	✅	✅	✅
`protected`	✅	✅	❌
`private`	✅	❌	❌

Public - Accessible Everywhere

<?php
class User {
    public $name;  // Accessible anywhere
}

$user = new User();
$user->name = "Alice";  // OK
?>

Protected - Class and Subclasses

<?php
class User {
    protected $email;  // Only in class and subclasses
}
// $user->email = "...";  // Error!
?>

Private - Class Only

<?php
class BankAccount {
    private $pin;  // Only within this class
    
    public function validatePin($pin) {
        return $this->pin === $pin;
    }
}
?>

Summary

public: Accessible everywhere
protected: Class + subclasses only
private: Class only
Encapsulation: Hide internal details

What's Next?

Next, learn about Inheritance - reusing code with the extends keyword!

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