使用面向对象编程在PHP中显示数组(Displaying Arrays in PHP using Object Oriented Programming)

 我在PHP中尝试PHP和面向对象编程。 当我尝试运行以下displayArray函数时，它根本不显示该行。 有谁知道我做错了什么？ 
 
<?php
class Student
{
    var $name;
    var $arr;

    function Student()
    {
        $this->name = "bob";
        $this->addnametostring("Hello there ");
        $this->arr = array();

        for($i=0; $i<30; $i++) {
            $arr[$i] = rand(0,100);
        }
    }

    function addnametostring($s)
    {
        $s.= " " . $this->name;
        echo "$s <br>";
    }

    function displayArray($amt)
    {
        foreach($this->arr as $key) { 
        //why is this not working
        echo "<br>hello: ".$key;
    }
}
 
 } 
 
$student = new Student;
echo "<br>";
$student->displayArray(20);

?>

I'm experimenting with PHP and object oriented programming in PHP. When I try to run the following displayArray function, it does not display the line at all. Does anyone know what I'm doing wrong?
 
<?php
class Student
{
    var $name;
    var $arr;

    function Student()
    {
        $this->name = "bob";
        $this->addnametostring("Hello there ");
        $this->arr = array();

        for($i=0; $i<30; $i++) {
            $arr[$i] = rand(0,100);
        }
    }

    function addnametostring($s)
    {
        $s.= " " . $this->name;
        echo "$s <br>";
    }

    function displayArray($amt)
    {
        foreach($this->arr as $key) { 
        //why is this not working
        echo "<br>hello: ".$key;
    }
}
 
}
 
$student = new Student;
echo "<br>";
$student->displayArray(20);

?>

原文：https://stackoverflow.com/questions/23379701