while loop

[mikemastah]

Hi I have a table in my MySQL DB 'shopitems' with the columns

id / name / attack / defence / costs / shop

which contains something like

grd / grenades / 800 / 0 / 950 / attack

snp / sniper / 1150 / 0 / 2000 / attack

etc. etc.

now in my shop i want to run the following code:

if ($_POST['grd']) {
   if (($_POST['grd'])*950 > $cash) {
       die (header("Location: /shop/money"));
   }
   else {
       $newgrenades = ($grenades + $_POST['grd']);
       mysql_query("UPDATE items SET grenades = '$newgrenades' WHERE username = '$nick'");
       $newatt = $attack + ($_POST['grd']*800);
       $newdef = $defence + ($_POST['grd']*0);
       $newcash = $cash - ($_POST['grd']*950);
       mysql_query("UPDATE users SET cashmoney = '$newcash', attack = '$newatt', defence = '$newdef' WHERE username = '$nick'");
   }
}

 

but then I would have to make that for every single item.

so I thought why not use a while loop. so here is my question.

Is it possible to use something like this?

(haven't tested it yet because my PHP installation is currently screwed up)

$q=mysql_query("SELECT * FROM shopitems");
while($shopitems=mysql_fetch_array($q)) {

if ($_POST[$shopitems['id']]) {
   if (($_POST[$shopitems['id']]*$shopitems['costs']) > $cash) {
       die (header("Location: /shop/money"));
   }
   else {
       $new = (${$shopitems['name']} + $_POST[$shopitems['id']]);
       mysql_query("UPDATE items SET $shopitems['name'] = '$new' WHERE username = '$nick'");
       $newatt = $attack + ($_POST[$shopitems['id']]*$shopitems['attack']);
       $newdef = $defence + ($_POST[$shopitems['id']]*$shopitems['defence']);
       $newcash = $cash - ($_POST[$shopitems['id']]*$shopitems['costs']);
       mysql_query("UPDATE users SET cashmoney = '$newcash', attack = '$newatt', defence = '$newdef' WHERE username = '$nick'");
   }
}

}

[Floydian]

Re: while loop

It does appear that you would be able to loop through all the rows in the table that way.

I'm not sure why you take an 'id' and multiply by 'costs'. I could see a 'qty' * 'costs'. But perhaps your naming conventions are just diff than mine.

So, I dun really get what exactly this code accomplishes, but it will iterate over all rows in that table. ;)

[mikemastah]

Re: while loop

 

I'm not sure why you take an 'id' and multiply by 'costs'. I could see a 'qty' * 'costs'. But perhaps your naming conventions are just diff than mine.

It actually is a quantity, I have an input field with id $shopitems['id'] which says how many you want.

${$shopitems['name']} and $_POST[$shopitems['id']] will work then? as I'm not that certain about the first one.

[Floydian]

Re: while loop

You've got the right idea, but you also have syntax errors:

$new = (${$shopitems['name']} + $_POST[$shopitems['id']]);

You've got a $ and a { and } just sitting in there, as if you are in a string context and you are not in a string context there.

[mikemastah]

Re: while loop

What I want to do is call an variable which is 'created' before this piece of code and the variable has the same name as $shopitems['name']

So when "$shopitems['name'] === grenades" I need to call $grenades..

can this be done easily or do I need a switch?

[Floydian]

Re: while loop

Variable variables....

 

$$shopitems['name'] // assuming $shopitems['name'] holds the value of grenades

is equivalent to:

$grenades

http://us2.php.net/manual/en/language.v ... riable.php

[mikemastah]

Re: while loop

wow ok cool thanks

[DELETE ME NOW!]

Re: while loop

Floydian thanks for this link (http://us2.php.net/manual/en/language.v ... riable.php) ty

[Floydian]

Re: while loop

You're welcome Crazy-T and mikemastah

 

Do keep in mind that if you ever do something like

$blah = $_GET['id'];

$foo = $_GET['amount'];

$$blah = $foo;

That you have a SERIOUS SECURITY risk. Use variable variables with caution :)