Métro
Sunday, February 26th, 2006
(*ack!* Wordpress ate my post!)
Archive for February, 2006
Demo for Luhn algorithm in PHP
Friday, February 24th, 2006If you have a number that adheres to the Luhn algorithm for validation, you may check it easily with this short PHP snippet.
<?php
function luhn($str) {
$odd = !strlen($str)%2;
$sum = 0;
for($i=0;$i<strlen($str);++$i) {
$n=0+$str[$i];
$odd=!$odd;
if($odd) {
$sum+=$n;
} else {
$x=2*$n;
$sum+=$x>9?$x-9:$x;
}
}
return(($sum%10)==0);
}
$num = $_GET[‘number’];
?>
<!DOCTYPE HTML PUBLIC “-//W3C//DTD HTML 4.01//EN” “http://www.w3.org/TR/html4/strict.dtd”>
<html>
<head>
<title>Online Luhn algorithm test</title>
<meta http-equiv=“Content-Type” content=“text/html; charset=ISO-8859-1″>
</head>
<body>
<?php if($num) { ?>
<?php if(luhn($num)) { ?>
<div style=“background:#ddffdd;border:1px solid #004400;”>
<?=htmlspecialchars($num)?> is valid
</div>
<?php } else { ?>
<div style=“background:#ffdddd;border:1px solid #880000;”>
<?=htmlspecialchars($num)?> is NOT valid
</div>
<?php } ?>
<?php } ?>
<form action=“luhn.php” method=“GET”>
<div>
Number: <input type=“text” name=“number” value=“<?=urlencode($num)?>” size=“40″/>
<input type=“button” name=“btSend” value=“Check”/>
</div>
</form>
</body>
function luhn($str) {
$odd = !strlen($str)%2;
$sum = 0;
for($i=0;$i<strlen($str);++$i) {
$n=0+$str[$i];
$odd=!$odd;
if($odd) {
$sum+=$n;
} else {
$x=2*$n;
$sum+=$x>9?$x-9:$x;
}
}
return(($sum%10)==0);
}
$num = $_GET[‘number’];
?>
<!DOCTYPE HTML PUBLIC “-//W3C//DTD HTML 4.01//EN” “http://www.w3.org/TR/html4/strict.dtd”>
<html>
<head>
<title>Online Luhn algorithm test</title>
<meta http-equiv=“Content-Type” content=“text/html; charset=ISO-8859-1″>
</head>
<body>
<?php if($num) { ?>
<?php if(luhn($num)) { ?>
<div style=“background:#ddffdd;border:1px solid #004400;”>
<?=htmlspecialchars($num)?> is valid
</div>
<?php } else { ?>
<div style=“background:#ffdddd;border:1px solid #880000;”>
<?=htmlspecialchars($num)?> is NOT valid
</div>
<?php } ?>
<?php } ?>
<form action=“luhn.php” method=“GET”>
<div>
Number: <input type=“text” name=“number” value=“<?=urlencode($num)?>” size=“40″/>
<input type=“button” name=“btSend” value=“Check”/>
</div>
</form>
</body>
(Download)
You may test this script at http://javier.rodriguez.org.mx/code/luhn-test.php.
Please consider that this is a demo, so please do not use this to check credit card numbers unless you send me an expiry date. CCV2 has taken over as the preferred method for credit card number validation anyway.
The best blonde joke ever
Thursday, February 16th, 2006It might be based on a silly stereotype, but this is the best blonde joke ever.
