JuniorTheoryCommon

What happens when you run this program?

PHP

<?php

class Account
{
    public function __construct(private int $balance) {}
}

$acc = new Account(50);
echo 'ok', "\n";
echo $acc->balance, "\n";

ok, then an Error: cannot access private property

Expecting 50, as if promotion made the property public: private int $balance declares a private property, and reading it outside Account throws an Error.
Expecting a Warning and an empty value: a private property is not a missing one, so reading it from outside throws an Error and stops the script.

How would you let outside code read the balance without letting it change the balance?
Which code may read $this->balance without an error?

JuniorTheoryCommon

PHP

<?php

class Account
{
    public function __construct(private int $balance) {}
}

$acc = new Account(50);
echo 'ok', "\n";
echo $acc->balance, "\n";

ok, then an Error: cannot access private property

Expecting 50, as if promotion made the property public: private int $balance declares a private property, and reading it outside Account throws an Error.
Expecting a Warning and an empty value: a private property is not a missing one, so reading it from outside throws an Error and stops the script.

How would you let outside code read the balance without letting it change the balance?
Which code may read $this->balance without an error?