[SOLVED] setting a value

[ngreenwood6]

I have a script that puts a user inputted value into the database.  It can be put in as either a debit or a credit. If it is a credit it will be positive and if it is a debit it will be negative.  I have created a drop down box that allows them to select debit or credit. However I just want them to be able to select either debit or credit and if it is debit automatically put a "-" in front of the number. The reason is because later it is called and the values are added. If not the user will have to put a "-" when they enter the value. Does anyone know how I can do this?  I have something like this but it doesnt work:

 

if($type == "Debit")
{
$amount = "-$amount";
}

 

I have tried some others but none seem to work. Any help is appreciated.

[sh0wtym3]

I need to see more of your code to help but, try using this:

 

if($type == "Debit") {
$newamount=.'-'.$amount;
}

 

... And then insert $newamount into your database.

 

And where is your $amount variable originally being called? If the number is being input by a user, there should be a line of code somewhere that looks something like:

 

$amount= $_POST['amount'];

 

(That's assuming you've named your text input box "amount")

[DarkWater]

Well, think about what a negative number is.  You can change a number to its negative with a general equation like:

0 - x = -x

 

So, by that logic:

if ($type == "Debit") {
        $newamount = 0 - (int) $amount;
}

[AndyB]

Improved variant:

 

if ($type=="Debit") {
    $amount = 0 - abs($amount);
}

 

Generates a negative value for $amount even if the user mistakenly places a negative sign before their input debit value.

[ngreenwood6]

I have tried all of your suggestions but none of them seem to work properly for me. Any other suggestions?

[sh0wtym3]

Can you post your entire code?

[ngreenwood6]

Sorry actually this topic is solved. I had the query above the part where I changed the value of $amount. When I moved it below it works properly. Thanks for all the help.

 

However, someone can someone explain to me what the abs() function does?

[DarkWater]

It returns the absolute value of a number.