Online PHP editor | output for kVeDt

<?php class B { public $str; function __construct($str) { $this->str = $str; } } class M extends B {} class C extends B {} function compare($a, $b) { $result = []; if ($a < $b) { $result[] = '<'; } if ($a > $b) { $result[] = '>'; } if ($a != $b) { $result[] = '!='; } if ($a == $b) { $result[] = '=='; } return $result; } assert(['=='] === compare(new C('A'), new C('A'))); assert(['<', '!='] === compare(new C('A'), new C('B'))); assert(['>', '!='] === compare(new C('Z'), new C('X'))); assert(['!='] === compare(new M('A'), new C('B'))); assert(['!='] === compare(new B('A'), new C('B'))); assert(['<', '!='] === compare(new M('A'), new M('B')));