3v4l.org

run code in 300+ PHP versions simultaneously
<?php $i = 1; $n = 2; for($f = 0; $f <= 20; $f++) { echo "F".$f." = ".intval((($f-$i)+($f-$n)))."\n"; $i++; $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, 5.5.24 - 5.5.35, 5.6.8 - 5.6.28, 7.0.0 - 7.0.20, 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 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
F0 = -3 F1 = -3 F2 = -3 F3 = -3 F4 = -3 F5 = -3 F6 = -3 F7 = -3 F8 = -3 F9 = -3 F10 = -3 F11 = -3 F12 = -3 F13 = -3 F14 = -3 F15 = -3 F16 = -3 F17 = -3 F18 = -3 F19 = -3 F20 = -3
preferences:
206.2 ms | 406 KiB | 326 Q