<?php 
function alphanumericPass() 
{    
    // Do not modify anything below here 
    $underscores = 2; // Maximum number of underscores allowed in password 
    $length = 10; // Length of password 
    
    $p =""; 
    for ($i=0;$i<$length;$i++) 
    {    
        $c = mt_rand(1,7); 
        switch ($c) 
        { 
            case ($c<=2): 
                // Add a number 
                $p .= mt_rand(0,9);    
            break; 
            case ($c<=4): 
                // Add an uppercase letter 
                $p .= chr(mt_rand(65,90));    
            break; 
            case ($c<=6): 
                // Add a lowercase letter 
                $p .= chr(mt_rand(97,122));    
            break; 
            case 7: 
                 $len = strlen($p); 
                if ($underscores>0&&$len>0&&$len<($length-1)&&$p[$len-1]!="_") 
                { 
                    $p .= "_"; 
                    $underscores--;    
                } 
                else 
                { 
                    $i--; 
                    continue; 
                } 
            break;        
        } 
    } 
    return $p; 
} 
?>