Online PHP editor | output for 3rl23

<?php class SomeHelperClass { public $_arr = []; public function addValue($value, $key = null): void { if ($key !== null) { $this->_arr[$key] = $value; } else { for ($i = 0, $count = count($this->_arr); $i <= $count; ++$i) { if (!key_exists($i, $this->_arr)) { $this->_arr[$i] = $value; break; } } } } } $test = new SomeHelperClass; var_export($test->_arr); echo "\n"; $test->addValue(1); var_export($test->_arr); echo "\n"; $test->addValue(2); var_export($test->_arr); echo "\n"; $test->addValue(3, 4); var_export($test->_arr); echo "\n"; $test->addValue(4, 3); var_export($test->_arr); echo "\n"; $test->addValue(5); var_export($test->_arr);