3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php $trx_nb = array(); if(isset($trx_nb[1])){ $trx_nb[1] +=1; }else{ $trx_nb[1] =1; } echo $trx_nb[1]; $trx_nb[1] +=1; echo $trx_nb[1]; $trx_nb[1] +=1; echo $trx_nb[1]; $trx_nb[1] +=1; echo $trx_nb[1];
based on 5mApv
Output for 4.3.0 - 5.6.28, hhvm-3.10.0 - 3.12.0, 7.0.0 - 7.1.0
1234