A blueprint for a PHP class

Here’s the full example:

<?php

// 🚁 A class is a blueprint for creating objects (instances).
class Helicopter
{
    /* ---------------------------------
     * 🏷️ PROPERTIES (variables that belong to the class)
     * --------------------------------- */

    // A constant value that never changes
    public const TYPE = "Utility Helicopter";

    // Public property → accessible from anywhere
    public $model;

    // Protected property → accessible only inside this class and child classes
    protected $maxSpeed;

    // Private property → accessible only inside this class
    private $engineStarted = false;

    // Static property → belongs to the class, not to objects
    public static $electricity = true;


    /* ---------------------------------
     * 🏗️ CONSTRUCTOR
     * --------------------------------- */

    // Constructor runs automatically when you create an object
    public function __construct($model, $maxSpeed)
    {
        $this->model = $model;
        $this->maxSpeed = $maxSpeed;

        echo "Helicopter {$this->model} created with max speed of {$this->maxSpeed} km/h.\n";
    }


    /* ---------------------------------
     * ⚙️ INSTANCE METHODS
     * --------------------------------- */

    // Normal method that works with the object (needs $this)
    public function startEngine()
    {
        $this->engineStarted = true;
        echo "Engine started for {$this->model}.\n";
    }

    // Another instance method
    public function fly()
    {
        if ($this->engineStarted) {
            echo "{$this->model} is flying at {$this->maxSpeed} km/h.\n";
        } else {
            echo "Start the engine first!\n";
        }
    }

    // Getter method for a private property
    public function isEngineStarted()
    {
        return $this->engineStarted;
    }


    /* ---------------------------------
     * 🛰️ STATIC METHODS
     * --------------------------------- */

    // Static method belongs to the class, not objects
    public static function checkElectricity()
    {
        if (self::$electricity) {
            echo "Electric systems are powered.\n";
        } else {
            echo "No electricity available.\n";
        }
    }
}


/* ---------------------------------
 * 🚀 USING THE CLASS
 * --------------------------------- */

// Create an object (instance) of Helicopter
$hely = new Helicopter("Apache", 300);

// Call instance methods
$hely->startEngine();
$hely->fly();

// Call static method (without creating an object)
Helicopter::checkElectricity();

// Accessing a constant
echo "This is a " . Helicopter::TYPE . "\n";

Explanation of important pieces

• public $model; → properties are like variables, but tied to the object.
• __construct() → constructor, runs when new Helicopter(...) is called.
• $this->... → refers to the current object.
• private $engineStarted; → encapsulation: outside code can’t change it directly.
• public function fly() → normal method, uses instance data.
• public static function checkElectricity() → class-level method, doesn’t need an object.
• self::TYPE / Helicopter::checkElectricity() → use :: for constants and static methods.