PHP array_rand奇怪的行为

Question

I was trying to create a simple password generator and noted that array_rand() returns the same results. Here is the code:

<?php
function generatePass() {
    $password = '';
    $a = explode(' ', 'q w e r t y u i o p a s d f g h j k l z x c v b n m');
    for($i=0; $i < rand(1,200); $i++) {
        $password .= $a[array_rand($a)];
    }
    return $password;
}

$r = 0;

while ($r <= 10000) { #generating 10 000 passwords
    $total[] = generatePass();
    $r++;
}
echo '<pre>';
print_r($total);
echo '</pre>';
?>

The $total array basically contains the same results repeated over and over again; if I refresh the page, only the order of elements changes, and not their values.

The question is: is this an expected behaviour or am I doing something wrong? Thak you for your attention.

Answer 1

Reseed the random number generator with srand() just prior to calling array_rand.

srand();
$password .= $a[array_rand($a)];