3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a0 = 'ab'; $a1 = 'a'; $a2 = 'b'; print ${$a1 + $a2};
Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
Fatal error: Uncaught TypeError: Unsupported operand types: string + string in /in/2rfhB:7 Stack trace: #0 {main} thrown in /in/2rfhB on line 7
Process exited with code 255.
Output for 7.1.0 - 7.1.25, 7.2.0 - 7.2.33, 7.3.0 - 7.3.31, 7.4.0 - 7.4.33
Warning: A non-numeric value encountered in /in/2rfhB on line 7 Warning: A non-numeric value encountered in /in/2rfhB on line 7 Notice: Undefined variable: 0 in /in/2rfhB on line 7
Output for 7.3.32 - 7.3.33
Warning: A non-numeric value encountered in /in/2rfhB on line 7 Warning: A non-numeric value encountered in /in/2rfhB on line 7
Output for 5.4.2 - 5.4.45, 5.5.24 - 5.5.35, 5.6.7 - 5.6.28, 7.0.0 - 7.0.20
Notice: Undefined variable: 0 in /in/2rfhB on line 7

preferences:
191.43 ms | 402 KiB | 242 Q