3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php $i = 1; for($f = 0; $f <= 20; $f++) { echo "F".$f." = ".(($f-1)+$f-2)."\n"; $i++; }
based on qEuf5
Output for 4.3.0 - 5.6.28, hhvm-3.12.0, 7.0.0 - 7.1.0
F0 = -3 F1 = -1 F2 = 1 F3 = 3 F4 = 5 F5 = 7 F6 = 9 F7 = 11 F8 = 13 F9 = 15 F10 = 17 F11 = 19 F12 = 21 F13 = 23 F14 = 25 F15 = 27 F16 = 29 F17 = 31 F18 = 33 F19 = 35 F20 = 37
Output for hhvm-3.10.0

Process exited with code 153.