3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = 5; $i = 4; for($i = &$a; $i < 10; ++$i); echo "a=$a, i=$i";
Output for 7.1.0 - 7.1.25, 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 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4
a=10, i=10

preferences:
128.39 ms | 403 KiB | 167 Q