<?php   session_start();        ?>

<?php
        $pass = $_SESSION['psw'];
        if($pass != "hw4c") print "Go away.";
        else
        {
?>

<FONT color=blue size=4>
<?php
        $op = $_POST['op'];     // "add",
        $num1 = $_SESSION['v1'];
        $num2 = $_SESSION['v2'];

        print "The num1 is $num1<BR>";
        print "The num2 is $num2<BR>";
        print "The operator is $op <HR>";

        if($op == "add")
        {       $ans = $num1 + $num2;
                print "$num1 + $num2 = $ans";
        }
        else if($op == "sub")
        {       $ans = $num1 - $num2;
                print "$num1 - $num2 = $ans";
        }
        else if($op == "mul")
        {       $ans = $num1 * $num2;
                print "$num1 * $num2 = $ans";
        }
        else if($op == "div")
        {       $ans = $num1 / $num2;
                print "$num1 / $num2 = $ans";
        }
	else if($op == "mod")
        {       $ans = $num1 % $num2;
                print "$num1 % $num2 = $ans";
        }
	else if($op == "exp")
        {       $ans = pow( $num1, $num2);
                print "$num1 ^ $num2 = $ans";
        }
?>
</FONT>

<?php
        }
?>