PHP实现通过Luhn算法校验信用卡卡号是否有效_php技巧

本文实例讲述了PHP实现通过Luhn算法校验信用卡卡号是否有效的方法。分享给大家供大家参考。具体实现方法如下：

$numbers = "49927398716 49927398717 1234567812345678 1234567812345670";
foreach (split(' ', $numbers) as $n)
  echo "$n is ", luhnTest($n) ? 'valid' : 'not valid', '';
 
function luhnTest($num) {
  $len = strlen($num);
  for ($i = $len-1; $i >= 0; $i--) {
    $ord = ord($num[$i]);
    if (($len - 1) & $i) {
      $sum += $ord;
    } else {
      $sum += $ord / 5 + (2 * $ord) % 10;
    }
  }   
  return $sum % 10 == 0;
}

运行结果

49927398716 is valid
49927398717 is not valid
1234567812345678 is not valid
1234567812345670 is valid

下面是一个更为简洁的代码：

function luhn_test($num) {
$str = '';
foreach( array_reverse( str_split( $num ) ) as $i => $c ) $str .= ($i % 2 ? $c * 2 : $c );
return array_sum( str_split($str) ) % 10 == 0;
}
foreach (array('49927398716','49927398717','1234567812345678','1234567812345670') as $n)
echo "$n is ", luhn_test($n) ? 'valid' : 'not valid', "\n";

输出结果如下

49927398716 is valid
49927398717 is not valid
1234567812345678 is not valid
1234567812345670 is valid

希望本文所述对大家的php程序设计有所帮助。