小编Col*_*els的帖子

我有一个简单的代码示例,我想设置私有属性$ ttlBal.

<$php
$balance = new Customer;
$greeting = fopen("greeting.txt", "r");
while(!feof($greeting)){
    echo fgets($greeting) . "<br>";
}
fclose($greeting);
$balance->acctBal = 12;
$balance->deposits = 12;
$balance->fdr = 12;


$balance->findAvail($balance->acctBal, $balance->deposits, $balance->ttlBal);
class Customer{
    public $acctBal; 
    public $deposits;
    private $acctAvail;
    private $ttlBal;
    public $fdr;

    public function findAvail($bal, $dep, $ttlBal){
        echo $this->ttlBal = $bal - $dep;
    }
}
?>

这会导致我无法访问私有属性$ ttlBal的错误.我可以通过哪种方式访问​​它.