Online PHP editor | output for r8E6u

<?php if (isset($test) && $test != NULL) { echo '$test set and not null'; } else { echo '$test not set and not null'; } $test = ''; if (isset($test) && $test != NULL) { echo '$test set and not null'; } else { echo '$test not set and not null'; } if (isset($test)) { echo '$test set, even when null'); } $test = "abc"; if (isset($test) && $test != NULL) { echo '$test set and not null'; } else { echo '$test not set and not null'; }