3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = null; $a--; var_dump($a); $a = null; $a++; var_dump($a); $a = null; $a-=1; var_dump($a);
Output for 4.3.1 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.24 - 5.5.35, 5.6.7 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.20, 7.2.0 - 7.2.33, 7.3.16 - 7.3.30, 7.4.0 - 7.4.23, 8.0.0 - 8.0.10, 8.1rc1 - rc2
NULL int(1) int(-1)

preferences:
89.7 ms | 462 KiB | 5 Q