Quick Function Infinite Loop Question, Error.

[Pass341]

Just a really quick question if anyone would be willing to help me. I can't seem to understand why my program:

<?php
function create_passwd() {
 #creates random 8-char alphanumeric password

 $length=8;
 $list=array_merge(range('a','z'),range(0,9));
 shuffle($list);
 $passwd=substr(join($list),0,$length);

 return $passwd;
}

function valid_email($email) {
 #this function takes a string and checks it against a regular expression, 
 #to ensure it's a valid email address.
 $good_email = "([a-zA-Z0-9]+@[a-zA-Z0-9_-]+\.[a-zA-Z0-9_-]+)+";
 if (preg_match("/$good_email/", $email)) {
 echo $email." is a valid email address.<br>";
 return true;
 }
 else {
 echo $email." is NOT a valid email address.<br>";
 return false;
 }
}

$user_array = array( array('email' => "[e-mail]", 'password' => ''),
 array('email' => "george@blah", 'password' => ''),
 array('email' => "[e-mail]", 'password' => ''),
 array('email' => "*@aol.com", 'password' => ''),
 array('email' => "nobody", 'password' => ''));

#filter array for invalid email entries
$index = 0;
while ($index < count($user_array)) {
 $next_user = $user_array[$index];
 if (valid_email($next_user['email'])) {
 $user_array[$index]['password'] = create_passwd();
 }
 else {
 #set the user_array entry to null, for later deletion.
 $user_array[$index] = null;
 }
 $index;
}
//now delete all NULL entries
$user_array = array_filter($user_array);
?><pre>
print_r($user_array);
?></pre>

When run, displays:

[e-mail] is a valid email address.

Infinitely. I'm guessing it has something to do with the function. Is it because I'm not telling the function how many times to display it or something? Please Help.

[bradgrafelman]

Your while() loop never increments $index. Also note that this statement towards the end of the loop:

$index; 

does nothing.

Note that the while() construct you've got -- initialize counter before loop, check counter in loop condition, increment counter near end of loop -- could be more compactly (and better, IMHO, as far as readability is concerned) written using a [man]for[/man] loop instead.

Then again, you could further reduce the code by using a [man]foreach[/man] loop and getting rid of the counter variable altogether.

[Pass341]

Wow, that makes sense. I kept asking it to analyze the same email instead of asking it to go on the the next one. So actually the "$index;" that seems like it has no use was supposed to be the increment, I just forgot to add the "++" after it.

Anyways, thanks a bunch.