Function not working

[andy1212]

So I'm trying to test out a calculator just to play around with php and I can't seem to get the calculator to do any math.

 

When I test out just adding, subtracting, multiplying numbers like this, $test = 1+2*4-5; and echo $test it shows the result which is 7. But when I make a form and allow myself to enter in numbers, it's like it doesn't recognize the variables as numbers. Here's the code I have,

<?


if (isset($_POST['item_name'], $_POST['item_price'], $_POST['item_age'], $_POST['conditiondrop'])) {
$item_name = $_POST['item_name'];
$item_price = $_POST['item_price'];
$item_age = $_POST['item_age'];
$condition = $_POST['conditiondrop'];


$errors = array();


$value1 = intval(strval($item_age*0.1));


if ($condition == 'excellent') {
$value = intval(strval($item_price-$value1));
}


if ($condition == 'good') {
$value = intval(strval($item_price-$item_price*0.05+$value1));
}


if ($condition == 'ok') {
$value = intval(strval($item_price-$item_price*0.1+$value1));
}


if ($condition == 'needstlc') {
$value = intval(strval($item_price-$item_price*0.2+$value1));
}
}


?>
Cost Calc:


<form action="" method="post">
item name:<br />
<input type="text" name="item_name" /><br />
item purchase price:<br />
<input type="text" name="item_price" /><br />
item age:<br />
<input type="text" name="item_age" /><br />
item condition:<br />
<select name="conditiondrop">
    <option name="excellent">excellent condition</option>
    <option name="good">good condition</option>
    <option name="ok">ok condition</option>
    <option name="needstlc">needs some tlc</option>
</select><br />
<input type="submit" />
</form><br /><br />


<? 
echo
$item_name.'<br />'.
$condition.'<br />'.
$value1.'<br />'.
$value
;
?>

So I can echo out item_name and condition fine but value1 and value don't get echoed out.

 

Thanks for your time and help in advance.

[kicken]

Your use of intval(strval( is a bit odd, and completely unnecessary. What values are you entering into your text boxes for item_price and item_age? Are you including any non-numeric symbols (ie, $, comma)? PHP will convert the values to a number for the math automatically, but if they contain those extra symbols the conversion may fail and you'd get unexpected results.

 

Use var_dump when outputting your values for debugging so you can see exactly what they contain, a simple echo does not always tell the whole story.

 

Rather than make the value of $condition a string which you then compare against to change the equation, you could just make it's value the percentage off and use it directly in the equation.

 

ie:

<select name="conditiondrop">
    <option name="0">excellent condition</option>
    <option name="0.05">good condition</option>
    <option name="0.1">ok condition</option>
    <option name="0.2">needs some tlc</option>
</select>

$value = $item_price-$item_price*$condition+$value1;

Bonus math tip:

$item_price - $item_price*0.1

could be written more simply as:

$item_price*0.9

Taking 10% off of something, is the same as taking 90% of it's value.

[andy1212]

ok thanks