Objects

<?php
class Dog
{
    public string $name = "";

    public function bark(): string
    {
        return $this->name . " says woof!";
    }
}

$a = new Dog();
$a->name = "Bruno";

$b = new Dog();
$b->name = "Luna";

echo $a->bark() . "\n";
echo $b->bark();

Bruno says woof!
Luna says woof!

<?php
class Counter
{
    public int $count = 0;
}

$one = new Counter();
$two = new Counter();

$one->count = 5;

echo $one->count . " and " . $two->count;

5 and 0

<?php
class Box
{
    public int $items = 1;
}

$a = new Box();
$b = $a;          // same object

$b->items = 99;

echo $a->items;

99

<?php
class Box
{
    public int $items = 1;
}

$a = new Box();
$b = clone $a;    // a separate copy

$b->items = 99;

echo $a->items . " and " . $b->items;

1 and 99

<?php
class Point
{
    public function __construct(public int $x = 0, public int $y = 0) {}
}

$a = new Point(1, 2);
$b = new Point(1, 2);
$c = $a;

var_dump($a == $b);    // same class, same values
var_dump($a === $b);   // different objects
var_dump($a === $c);   // the same object

bool(true)
bool(false)
bool(true)

<?php
class Cat {}
$cat = new Cat();

var_dump($cat instanceof Cat);
echo get_class($cat) . "\n";
echo $cat::class;

bool(true)
Cat
Cat

<?php
class Task
{
    public function __construct(public string $title, public bool $done = false) {}
}

$tasks = [new Task("Write"), new Task("Test", true)];

foreach ($tasks as $task) {
    echo $task->title . ": " . ($task->done ? "done" : "open") . "\n";
}

Write: open
Test: done

<?php
class Plain {}

$p = new Plain();
$p->surprise = "not declared";

Deprecated: Creation of dynamic property Plain::$surprise is deprecated in /path/to/index.php on line 5