自定义函数

<?php
echo "<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]);
	}
?>