自定义函数

<?phpecho "<form action='' method='post'>";echo "Number Conmand:<input name='text' type='text'>";echo "<input type='submit' name='sub' value='check'>";echo "</form>";define("PI",3.1415926);function Encrypt($str){return $str=$str+PI;}function Decrypt($str){return $str=$str-PI;}if($_POST[sub]){echo "encryption conmand  ".Encrypt($_POST[text])."<br>";$_SESSIION[pwd]=Encrypt($_POST[text]);?><a href='44.php?pwd=1'>decrypt conmand</a><?php}if(isset($_GET[pwd])){echo "decrypt conmand  ".Decrypt($_SESSION[pwd]);}?>