Online PHP editor | output for Kgos7

@ 2014-08-01T12:33:42Z

<?php
$array1 = array('A', 'B');
$array2 = array('1', '2', '3');

$num = count($array2); 

//The total number of possible combinations 
$total = pow(2, $num);
$temp = array();

//Loop through each possible combination  
for ($i = 0; $i < $total; $i++) 
{  
    //For each combination check if each bit is set 
    for ($j = 0; $j < $num; $j++) 
    { 
       //Is bit $j set in $i? 
        if (pow(2, $j) & $i) $ff = $ff.''.$array2[$j];
    }
}

print_r($ff);

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: Warning: Undefined variable $ff in /in/Kgos7 on line 18 121231323123
Output for 5.0.4 - 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, 5.6.7 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.20, 7.2.0 - 7.2.33, 7.3.12 - 7.3.31, 7.4.0 - 7.4.33: Notice: Undefined variable: ff in /in/Kgos7 on line 18 121231323123
Output for 7.3.32 - 7.3.33: 121231323123
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.3: Notice: Undefined variable: ff in /in/Kgos7 on line 18 121231323123

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