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<?php function GetLuhnCheckDigit($number) { $sum = 0; $alt = true; $digits = str_split($number); for ($i = count($digits) - 1; $i >= 0; $i--) { $curDigit = $digits[$i]; if ($alt) { $curDigit *= 2; if ($curDigit > 9) $curDigit -= 9; } $sum += $curDigit; $alt = false; } if (($sum % 10) == 0 ){ return 0; } echo abs($sum) . PHP_EOL; return (10 - (abs($sum) % 10)); } echo GetLuhnCheckDigit(1234567891234567891);
Output for 5.5.0 - 5.5.38, 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 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 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4
92 8

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264.91 ms | 407 KiB | 326 Q