Generate random code using PHP

Below is the function to generate a random code(alpha-numeric) using PHP. We can use the below function for generating a coupon code (or) verification code (or) affiliate code for the people.

function generate_random_code( $size )
{
        $list_chars = array_merge(range('A','Z'), range(0,9));
      
        $referal_code = '';
      
        for($i=0;$i<=$size;$i++)
        {
            $referal_code .= $list_chars[mt_rand(0, count($list_chars)-1)];
        }
      
        return $referal_code;
      
}

$size  => Length of the random code to be generated.