Why does PHP sum values of similar array items differently?

Question

Laravel 8 , php 8

I saw a very strange thing in Laravel and actually in PHP that I can't understand why this is happening in PHP.

I have two arrays that are almost identical and have only one very small difference. And the result of the operation of adding all the values ​​of the items of each of them is 100. But PHP considers the sum of the values ​​to be 100 for one of the arrays but not for the other. How is this possible?

Of course, I know a little about PHP_FLOAT_EPSILON l. But it seems that this variable has nothing to do with the problem that arose for me.

$c = [
    23.3,
    33.4,
    43.3,
];
$d = [
    43.3,
    23.4,
    33.3,
];

$ccc = array_sum($c);
$ddd = array_sum($d);

dump($ccc);  // output: 100.0
dump($ddd);  // output: 100.0

if ($ccc != 100) {
    dump('$ccc is not equal to 100');
} else {
    dump('$ccc is equal to 100');  // This output is displayed.
}
if ($ccc != 100.0) {
    dump('$ccc is not equal to 100.0');
} else {
    dump('$ccc is equal to 100.0');  // This output is displayed.
}

if ($ddd != 100) {
    dump('$ddd is not equal to 100');  // This output is displayed.
} else {
    dump('$ddd is equal to 100');
}
if ($ddd != 100.0) {
    dump('$ddd is not equal to 100.0');  // This output is displayed.
} else {
    dump('$ddd is equal to 100.0');
}