3v4l.org

run code in 300+ PHP versions simultaneously
<?php $flag = 2; // true if ($flag) echo "I am true.\n"; $flag = 0; // false if (!$flag) echo "I am false.\n"; $flag = -1; if ($flag) { echo "Null is true.\n"; } if (!$flag) { echo "Null is false.\n"; }
Output for 4.3.0 - 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, 5.5.0 - 5.5.38, 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
I am true. I am false. Null is true.
preferences:
297.3 ms | 406 KiB | 459 Q