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run code in 200+ php & hhvm versions
Bugs & Features
<?php $a= null; $b = 20; echo '<br>a-'. $a; $c = $b + $a; echo '<br>c-'.$c; $a = $a + $b; echo '<br>na-'.$a;
Output for 4.3.0 - 7.1.7
<br>a-<br>c-20<br>na-20