bnbweb/includes/lib_lottery.php

<?php

if (!defined('IN_ECS'))
{
    die('Hacking attempt');
}

function getRand($proArr) { 
    $result = ''; 
 
    //概率數組的總概率精度 
    $proSum = array_sum($proArr); 

    //概率數組循環 
    foreach ($proArr as $key => $proCur) { 
        $randNum = mt_rand(1, $proSum); 
        if ($randNum <= $proCur) { 
            $result = $key; 
            break; 
        } else { 
            $proSum -= $proCur; 
        } 
    } 
    unset ($proArr); 
 
    return $result; 
} 

?>