[Resolved] looping headache

[owaring]

I have a user input of first and last name, which my scrpit creates $fromid from. It is made of 3 letters of first name and 3 letters of last name, ie oliwar, chrlew, jeschr

In order to check if the user id is already taken i have written the following script.

The function checkid($id) sends a query to the db using the id and if it returns true a new id is needed.

The do while is where my problem lies it adds 1 to the end of $formid, however if there is already an id with a number on the end, it loops by trying 1 on the end of formid each time, always returning a negative result.

I figure i need to replace the ++ line with code that adds 1 each time it is run.

if(checkid($formid) == TRUE)//IF MATCH ADD 1 TO FORMID 
{echo "ID MATCHES AN ID IN DB</br>";

/*
		do
		{
		$n = substr($formid,0,6);
		$int = substr($formid,6,1);
		$int ++;
		$newid = ($n.$int);
		}
		while ((checkid($newid) == TRUE));
*/



$id = ($newid);}  

else
{$id = $formid;}//IF NO MATCH OF ID IN DB, ID = FORMID

echo $id;

Advance thanks

[mtmosier]

$n = substr($formid,0,6);
$int = substr($formid,6);  //  Int could be more than one character
do
{
    $int ++;
    $newid = ($n.$int);
}
while ((checkid($newid) == TRUE)); 

[owaring]

Thanks, that makes sense!

I seem to have a more fundamental problem somewhere though.

When an id is entered (line 13) that is not in db the script executes no problem.

When is in db and do while is deployed it seems to crash, and a reboot of web server is all i can find that will return me to safety.

The whole script is here but i fugure it is in the if condition block of statements.

<?
include("../include/functions.php");

accessdb();

function checkid($var)
{$idquery = "SELECT * FROM crew WHERE id='$var'";
		 $result = mysql_query($idquery)
			or die ("Couldn't execute id query.");
		 $row = mysql_fetch_array($result);
		 return $row;}

$formid = oliwar;

if(checkid($formid) == TRUE)//IF MATCH IN DB ADD 1 UNTIL NO MATCH
	{
	$n = substr($formid,0,6);
	$int = substr($formid,6);

	do	{
		$int ++;
		$newid = ($n.$int);
		}
		while (checkid($newid) == TRUE);

$id = $newid;  
}

else

{$id = $formid;}//IF NO MATCH OF ID IN DB, ID = FORMID

echo $id;
?>

Ideas??

[mtmosier]

$int starts out as nothing in this script. It seems that the "++" operator on a blank value returns blank, so you get an infinite loop. Try this:

$int = intVal(substr($formid,6));

[owaring]

Hoorray!

Cheers mtmosier

Does Intval convert the varialble to a int or define it as one?

[mtmosier]

Oh, I'm sorry. Shouldn't have assumed you were familiar with that function. intval will return the integer value of the parameter passed to it. It doesn't affect the original variable.