JuniorTheoryCommon

What does the program print?

PHP

<?php

class Point
{
    public function __construct(public int $x) {}
}

$a = new Point(1);
$b = $a;
$c = clone $a;
$b->x = 5;
echo $a->x, ' ', $b->x, ' ', $c->x, "\n";

5 5 1

Expecting 1 5 1, as if $b = $a copied the object like an array: it copies only the object handle, so $a and $b lead to one object.
Expecting clone to give one more name for the same object: it builds a second object with copies of the properties, so the later write misses $c.

What do $a === $b and $a === $c return here?
If a property of Point held another object, would clone copy that object too?

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JuniorTheoryCommon

What does the program print?

PHP

<?php

class Point
{
    public function __construct(public int $x) {}
}

$a = new Point(1);
$b = $a;
$c = clone $a;
$b->x = 5;
echo $a->x, ' ', $b->x, ' ', $c->x, "\n";

5 5 1

Expecting 1 5 1, as if $b = $a copied the object like an array: it copies only the object handle, so $a and $b lead to one object.
Expecting clone to give one more name for the same object: it builds a second object with copies of the properties, so the later write misses $c.

What do $a === $b and $a === $c return here?
If a property of Point held another object, would clone copy that object too?

Back to questions Open topic in roadmap →Answer it yourself — Quiz