Undefined variable error

tm2383 · 01-18-2013, 10:45 PM

Hi,
I've just bought the book PHP and MYSQL Web Development and have started to work through the examples. I'm running Linux Mint 14 with an Apache server. I installed PHP and MYSQL using Apache Friends. The server is started and simple PHP programs are working correctly. Code is saved to a 'tutorials' folder in apache htdocs using eclipse with the php plug-in.
I started a new php project in eclipse and added two files to the project. the first is an html file which I have called index.html. This is the code:

Code:

<html>
<head><title>Bob's Auto Parts</title></head>
<body>
<form action="processorder.php" method="post">
<table border="0">
<tr bgcolor="#cccccc">
  <td width="150">Item</td>
  <td width="15">Quantity</td>
</tr>
<tr>
  <td>Tires</td>
  <td align="center"><input type="text" name="tireqty" size="3"
     maxlength="3" /></td>
</tr>
<tr>
  <td>Oil</td>
  <td align="center"><input type="text" name="oilqty" size="3" 
     maxlength="3" /></td>
</tr>
<tr>
  <td>Spark Plugs</td>
  <td align="center"><input type="text" name="sparkqty" size="3"
     maxlength="3" /></td>
</tr>
<tr>
  <td>How did you find Bob's?</td>
  <td><select name="find">
        <option value = "a">I'm a regular customer</option>
        <option value = "b">TV advertising</option>
        <option value = "c">Phone directory</option>
        <option value = "d">Word of mouth</option>
      </select>
  </td>
</tr>
<tr>
  <td colspan="2" align="center"><input type="submit" value="Submit Order" /></td>
</tr>
</table>
</form>
</body>
</html>

Variable such as tireqty and oilqty are defined. The second file named processorder (defined as a form action in the html file) contains this code.

Code:

<html>
<head>
  <title>Bob's Auto Parts - Order Results</title>
</head>
<body>
<h1>Bob's Auto Parts</h1>
<h2>Order Results</h2>
<?php
  echo '<p>Order processed at ';
  echo date('H:i, jS F');
  echo '</p>';
  echo '<p>Your order is as follows: </p>';
  echo $tireqty.' tires<br />';
  echo $oilqty.' bottles of oil<br />';
  echo $sparkqty.' spark plugs<br />';

  $totalqty = 0;
  $totalamount = 0.00;

  $totalqty = 0;
  $totalqty = $tireqty + $oilqty + $sparkqty;
  echo 'Items ordered: '.$totalqty.'<br />';

  $totalamount = 0.00;

  define('TIREPRICE', 100);
  define('OILPRICE', 10);
  define('SPARKPRICE', 4);

  $totalamount = $tireqty * TIREPRICE
               + $oilqty * OILPRICE
               + $sparkqty * SPARKPRICE;

  echo 'Subtotal: $'.number_format($totalamount,2).'<br />';

  $taxrate = 0.10;  // local sales tax is 10%
  $totalamount = $totalamount * (1 + $taxrate);
  echo 'Total including tax: $'.number_format($totalamount,2).'<br />';

?>
</body>
</html>

These examples are copied direclty from the book.
Line 5 in the html code

Code:

<table border="0">

is generating a warning in eclipse and i get the following error when i run localhost/tutorials. Here is the error generated:

Code:

Bob's Auto Parts

Order Results

Order processed at 22:38, 18th January

Your order is as follows:


Notice: Undefined variable: tireqty in /opt/lampp/htdocs/tutorials/processorder.php on line 13
tires

Notice: Undefined variable: oilqty in /opt/lampp/htdocs/tutorials/processorder.php on line 14
bottles of oil

Notice: Undefined variable: sparkqty in /opt/lampp/htdocs/tutorials/processorder.php on line 15
spark plugs

Notice: Undefined variable: tireqty in /opt/lampp/htdocs/tutorials/processorder.php on line 21

Notice: Undefined variable: oilqty in /opt/lampp/htdocs/tutorials/processorder.php on line 21

Notice: Undefined variable: sparkqty in /opt/lampp/htdocs/tutorials/processorder.php on line 21
Items ordered: 0

Notice: Undefined variable: tireqty in /opt/lampp/htdocs/tutorials/processorder.php on line 31

Notice: Undefined variable: oilqty in /opt/lampp/htdocs/tutorials/processorder.php on line 32

Notice: Undefined variable: sparkqty in /opt/lampp/htdocs/tutorials/processorder.php on line 32
Subtotal: $0.00
Total including tax: $0.00

Can anyone help with these errors. Code is exactly as listed in the book.

Thanks,

Tim

AndrewGSW · 01-18-2013, 11:16 PM

You appear to be missing a chunk

. Re-examine the section of the book but, otherwise, you might need to search the books' website for errata.

Code like the following is missing:

PHP Code:


			
if (isset($_POST['tireqty']) && !empty($_POST['tireqty'])) {

    $tireqty = $_POST['tireqty'];

}

The warning for table is probably that it lacks the summary attribute, but this is no longer a requirement. and the attribute may even be dropped by W3C.

Code:

<tr bgcolor="#cccccc">

BTW This bgcolor attribute is obsolete, and your pages should have a DOCTYPE declaration - but we can blame the book for this!

Fou-Lu · 01-19-2013, 03:12 AM

Answer: toss your book. Its too old to work with (now 4.5 years old).
The error on an html element in eclipse is likely the use of deprecated HTML (border in table). Use CSS.
The problem with the PHP is it expects you have register_globals enabled. This directive has been disabled by default since 4.2, deprecated in 5.3, and removed in 5.4. As pointed out, all of your data must be extracted from a superglobal, which in this case is $_POST. You can however use isset() to check multiple conditions by giving all the arguments you expect, then within that block extract all the variables and process per normal.

AndrewGSW · 01-19-2013, 07:37 PM

@Fou-Lu. I'm so up-to-date that I didn't even know that register_globals existed

I recommend PHP and MySQL for Dynamic Web Sites: Visual QuickPro Guide by Larry Ullman (Sept 2011 - recent enough!).

tm2383 · 01-19-2013, 08:59 PM

Thanks for the replies everyone. The problem seems to have been that the script on the CD had missing code from it. By following the example in the book itself, I added the following code and got it to work:

Code:

$tireqty = $_POST ['tireqty'];
 $oilqty = $_POST ['oilqty']; 
 $sparkqty = $_POST ['sparkqty'];

Later in the book, better methods are discussed in the regex section.

Register_globals is discussed, although the book says never to use it due to security risks. The book uses 5.3 when it was still available.

The mysql API database connector used in the book is mysqli .

Will this book still do for the basics, do you think?

Thanks

Tim

AndrewGSW · 01-19-2013, 11:15 PM

Quote:

Will this book still do for the basics, do you think?

Yes, should be okay. I would supplement with reference to the online docs. Read the relevant pages as you go along; get to know the docs very well, particularly the comments.

The book should cover prepared statements. This is an important subject.

This site looks very good as well; although I've only come across it today.

PS Remove the space(s) $_POST ['tireqty'];