الفئات والكائنات

Procedural: You follow a checklist every time you bake a cake — crack eggs → add flour → mix → bake
Object-oriented: You have a "cake machine" (class). Press "make" and out comes a cake (object)

<?php
// Procedural: data and functions are scattered
$userName = "John";
$userAge = 25;
function greet($name) {
    return "Hello, {$name}";
}
echo greet($userName);

// Object-oriented: data and functions are bundled together
class User {
    public string $name;
    public int $age;
    
    function greet(): string {
        return "Hello, {$this->name}";
    }
}
$user = new User();
$user->name = "John";
$user->age = 25;
echo $user->greet();
?>

<?php
class Car {
    // Properties (data)
    public string $brand;
    public string $color;
    public int $year;
    
    // Methods (behavior)
    public function start(): string {
        return "{$this->brand} is starting!";
    }
    
    public function honk(): string {
        return "Beep beep!";
    }
}
?>

<?php
// From one blueprint (class), create three specific cars (objects)
$car1 = new Car();
$car1->brand = "Toyota";
$car1->color = "White";
$car1->year = 2024;

$car2 = new Car();
$car2->brand = "BMW";
$car2->color = "Black";
$car2->year = 2023;

echo $car1->start();  // Toyota is starting!
echo $car2->start();  // BMW is starting!

// Use the arrow operator -> to access properties and methods
echo $car1->brand;    // Toyota
$car1->color = "Red"; // Modify a property
echo $car1->color;    // Red
?>

<?php
class Car {
    public string $brand;
    public string $color;
    public int $year;
    
    // Constructor
    public function __construct(string $brand, string $color, int $year) {
        $this->brand = $brand;
        $this->color = $color;
        $this->year  = $year;
    }
    
    public function getInfo(): string {
        return "{$this->year} {$this->color} {$this->brand}";
    }
}

// Pass arguments when creating the object
$car = new Car("Toyota", "White", 2024);
echo $car->getInfo();  // 2024 White Toyota
?>

<?php
// PHP 8.0+ simplified syntax
class Car {
    public function __construct(
        public string $brand,
        public string $color,
        public int $year,
    ) {
        // Parameters automatically become properties! No more $this->brand = $brand
    }
}

$car = new Car("Toyota", "White", 2024);
echo $car->brand;  // Toyota ✅
?>

<?php
class BankAccount {
    public string $bank = "Bank of China";  // Anyone can see and modify
    private float $balance = 0;             // Only accessible inside the class
    protected string $accountId;            // Accessible inside the class and subclasses
    
    public function __construct(
        private string $owner,
        private float $initialDeposit = 0.0
    ) {
        $this->balance = $initialDeposit;
    }
    
    // Safely manipulate private properties through public methods
    public function deposit(float $amount): void {
        if ($amount > 0) {
            $this->balance += $amount;
        }
    }
    
    public function getBalance(): float {
        return $this->balance;
    }
}

$account = new BankAccount("John", 1000);
echo $account->bank;         // Bank of China ✅ public is accessible
$account->deposit(500);       // ✅ public method can be called
echo $account->getBalance(); // 1500 ✅
// echo $account->balance;   // ❌ Error: private property not directly accessible
// $account->balance = 9999; // ❌ Error: can't arbitrarily change the balance
?>

<?php
class User {
    public function __construct(
        public string $name,
        public int $age
    ) {}
}

$u1 = new User("John", 25);
$u2 = new User("John", 25);
$u3 = $u1;

var_dump($u1 == $u2);   // true (same property values)
var_dump($u1 === $u2);  // false (not the same object)
var_dump($u1 === $u3);  // true (pointing to the same object)
?>

<?php
class User {
    private string $passwordHash;  // Password hash—never exposed
    
    public function __construct(
        public string $username,
        public string $email,
        string $password,           // Regular parameter (not a property)
        public int $age = 0,
        public bool $isActive = true,
    ) {
        // Password is hashed during construction
        $this->passwordHash = password_hash($password, PASSWORD_DEFAULT);
    }
    
    public function verifyPassword(string $password): bool {
        return password_verify($password, $this->passwordHash);
    }
    
    public function getDisplayName(): string {
        return $this->username . ($this->isActive ? '' : ' (Deactivated)');
    }
    
    public function greet(): string {
        return "Hello, {$this->username}! Your email is {$this->email}.";
    }
}

// Usage
$user = new User("John", "john@example.com", "secret123", 25);

echo $user->greet();
echo "User status: " . $user->getDisplayName() . "<br>";

if ($user->verifyPassword("secret123")) {
    echo "Password correct!";
}
// echo $user->passwordHash; // ❌ Error: private, not accessible
?>