<?php
function assign_rand_value($num) {

  
    switch($num) {
        case "1"  : $rand_value = "a"; break;
        case "2"  : $rand_value = "b"; break;
        case "3"  : $rand_value = "c"; break;
        case "4"  : $rand_value = "d"; break;
        case "5"  : $rand_value = "e"; break;
        case "6"  : $rand_value = "f"; break;
        case "7"  : $rand_value = "g"; break;
        case "8"  : $rand_value = "h"; break;
        case "9"  : $rand_value = "i"; break;
        case "10" : $rand_value = "j"; break;
        case "11" : $rand_value = "k"; break;
        case "12" : $rand_value = "l"; break;
        case "13" : $rand_value = "m"; break;
        case "14" : $rand_value = "n"; break;
        case "15" : $rand_value = "o"; break;
        case "16" : $rand_value = "p"; break;
        case "17" : $rand_value = "q"; break;
        case "18" : $rand_value = "r"; break;
        case "19" : $rand_value = "s"; break;
        case "20" : $rand_value = "t"; break;
        case "21" : $rand_value = "u"; break;
        case "22" : $rand_value = "v"; break;
        case "23" : $rand_value = "w"; break;
        case "24" : $rand_value = "x"; break;
        case "25" : $rand_value = "y"; break;
        case "26" : $rand_value = "z"; break;
        case "27" : $rand_value = "0"; break;
        case "28" : $rand_value = "1"; break;
        case "29" : $rand_value = "2"; break;
        case "30" : $rand_value = "3"; break;
        case "31" : $rand_value = "4"; break;
        case "32" : $rand_value = "5"; break;
        case "33" : $rand_value = "6"; break;
        case "34" : $rand_value = "7"; break;
        case "35" : $rand_value = "8"; break;
        case "36" : $rand_value = "9"; break;
    }
    return $rand_value;
}

function get_rand_alphanumeric($length) {
    if ($length>0) {
        $rand_id="";
        for ($i=1; $i<=$length; $i++) {
            mt_srand((double)microtime() * 1000000);
            $num = mt_rand(1,36);
            $rand_id .= assign_rand_value($num);
        }
    }
    return $rand_id;
}

function get_rand_numbers($length) {
    if ($length>0) {
        $rand_id="";
        for($i=1; $i<=$length; $i++) {
            mt_srand((double)microtime() * 1000000);
            $num = mt_rand(27,36);
            $rand_id .= assign_rand_value($num);
        }
    }
    return $rand_id;
}

function get_rand_letters($length) {
    if ($length>0) {
        $rand_id="";
        for($i=1; $i<=$length; $i++) {
            mt_srand((double)microtime() * 1000000);
            $num = mt_rand(1,26);
            $rand_id .= assign_rand_value($num);
        }
    }
    return $rand_id;
}




?>