edward-jimenez · May 6, 2018 22:59
diff --git a/replace-string.php b/replace-string.php
 <?php

 /*

 Print the last 4 charactrs of a credit card number replacing the first 12 characters with asterisks

 using the PHP substr_replace function

 */

 ?>
 <!DOCTYPE html>

 <html>

 <head>

 	<meta charset="UTF-8">

 	<title>Replace String</title>

 </head>

 <body>

 <?php if($_SERVER['REQUEST_METHOD'] == 'GET') { ?>

 	<form method="POST" action="replace-string.php" >

 		<input type="text" name="credit_card" placeholder="Credit Card" size="16" />

 		<input type="submit" name="submit" value="Submit" />

 	</form>

 	<?php } else {

 		/* Returns the credit card variable with the first 12 digits replaced with 'x'
 		   substr_replace(<original_string>, <replacement_string>, <start>, <length>);
 		*/
 		$last_four = substr_replace($_POST['credit_card'], 'xxxx xxxx xxxx ', 0, strlen($_POST['credit_card']) - 4 );
 		echo "The last four of your credit card number is " . $last_four;

 	} ?>

 </body>

 </html>