Question

我创建了两个对象类：Student类和Dorm类。在宿舍类中，我创建了一个名为assign_to_dorm的方法，该方法应该计算宿舍中当前占用者的数量，如果等于或高于容量，则应返回false。如果低于capcity，则该方法将Student对象添加到Dorm类的占用者数组属性中。

这是我的宿舍课

<?php

    class Dorm
    {
        private $dorm_name;
        private $capacity;
        private $occupants = array();

       public function assign_to_dorm($student)
        {
           $ammount = count($this->occupants);

           if($ammount >= $this->capacity)
           {
                return FALSE;
           }else{
               array_push($occupants, $student);
           }
        }

       public function set_dorm_name($dorm_name)
        {
            $this->dorm_name = $dorm_name;
        }

        public function set_capacity($capacity)
        {
            $this->capacity = $capacity;
        }

        public function get_dorm_name()
        {
            return $this->dorm_name;
        }

        public function get_capacity()
        {
            return $this->capacity;
        }

        public function view_occupants()
        {
            foreach($this->occupants as $resident)
              {
                    echo "<br/>" . $resident;
              }
        }

        public function __construct($dorm_name,$capacity)
        {
            $this->set_dorm_name($dorm_name);
            $this->set_capacity($capacity);
        }  
    }
?>

在我的网站索引文件中，我创建了一个$ dorms数组和一个$ students数组，我将用它来测试该方法。然后我将学生列表拖沓，最后我让学生循环，这样就可以使用assign_to_dorm（）方法将它们添加到随机宿舍中。之后我希望它打印出宿舍里的居住者。

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>Assignment 3</title>
    </head>


    <body>
        <?php

            require('student.php');
            require('dorm.php');


            $dorms = array();
            $dorms[] = new Dorm("Lindo Hall", 50);
            $dorms[] = new Dorm("Smith Hall", 20);
            $dorms[] = new Dorm("Salley Hall", 200);

            $students = array();
            $students[] = new Student("Mike", "Lindo", "Senior", "Male");
            $students[] = new Student("Miguel", "Pakesh", "Freshman", "Male");
            $students[] = new Student("Sammie", "Maxwell", "Sophomore", "Female");
            $students[] = new Student("John", "Smith", "Junior", "Male");
            $students[] = new Student("Jane", "Doe", "Sophomore", "Female");
            $students[] = new Student("John", "Smith", "Senior", "Male");
            $students[] = new Student("Jane", "Doe", "Junior", "Female");
            $students[] = new Student("John", "Smith", "Freshman", "Male");
            $students[] = new Student("Jane", "Doe", "Freshman", "Female");
            $students[] = new Student("John", "Smith", "Sophomore", "Male");
            $students[] = new Student("Jane", "Doe", "Senior", "Female");
            $students[] = new Student("Chris", "Doe", "Freshman", "Male");
            $students[] = new Student("Sarah", "Smith", "Sophomore", "Female");
            $students[] = new Student("Chris", "Doe", "Junior", "Male");
            $students[] = new Student("Sarah", "Smith", "Senior", "Female");

            shuffle($students);

            foreach($students as $student)
            {

                 $dorm =& array_rand($dorms);          // LINE 47
                 $dorm->assign_to_dorm($student);      // LINE 48

            }

            echo "<table><tbody>";

            foreach($dorms as $dorm)
            {
                echo "<tr>";

                echo "<td>" . $dorm->view_occupants() . "</td>";

                echo "</tr>";
            }

        ?>
    </body>
</html>

我每次运行网站时都会收到这些错误：

严格标准：只应在第47行的C：\ Program Files \ EasyPHP-5.3.8.0 \ www \ assignment3 \ index.php中通过引用分配变量

致命错误：在第48行的C：\ Program Files \ EasyPHP-5.3.8.0 \ www \ assignment3 \ index.php中的非对象上调用成员函数assign_to_dorm（）

任何想法我可能做错了什么？我想在assign_to_dorm（）方法中的代码一定有问题，或者我仍然需要一个占用者数组的构造函数，我不认为这是问题。任何帮助是极大的赞赏。非常喜欢

Answer 1

现代PHP版本默认将returnin对象作为引用，因此=&赋值不是必需的。这是第一个警告。

第二个警告：array_rand返回一个数组KEY，而不是一个数组VALUE。所以你得到像5这样的东西，而不是你分配给阵列的第五个对象。

代码应为

$dorm_index = array_rand($dorms);          // LINE 47
$dorms[$dorm_index]->assign_to_dorm($student);      // LINE 48

Answer 2

来自http://php.net/array_rand

mixed array_rand ( array $input [, int $num_req = 1 ] )

Picks one or more random entries out of an array, and returns
the key (or keys) of the random entries.

它选择了关键......你需要说

$key = array_rand($dorms);

$dorm = $dorms[$key];

Answer 3

array_Rand不返回元素，它返回键。然后你需要获得元素：

$key = array_rand($dorms);          // LINE 47
$dorm = $dorms[$key];
$dorm->assign_to_dorm($student);

在我的PHP代码行中发生致命错误

3 个答案: