In PHP objects, methods refer to functions created in the class structure, which implement a behavior in the class and are part of the class; while attributes refer to variables directly declared in the class structure, in the object There can be multiple attributes, and each variable stores different attribute information of the object.
The operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer
First of all, let’s briefly understand the related concepts:
Class: class is the outermost structure that defines the object-oriented subject. It is also used to wrap the subject data and functions (functions). A class is a type of common affairs. Representative represents the commonality of affairs.
Object: Object is a specific representative of a certain type of transaction and a specific unit of actual data and functional operations. It is also called an instance.
Instantiation: new, the process of obtaining a specific instance that conforms to the abstract concept from an abstract concept.
##Class members: member refers to all the contents in the class structure. There are three types of class members;
Method: Method is essentially a function created in the class structure, also called a member method, or member function.
Property: Property is essentially a variable created in the class structure, also called a member variable.
Member attributes
Variables declared directly in a class are called member attributes (can also be called member variables). Multiple variables can be declared in a class, that is There can be multiple member attributes in an object, and each variable stores different attribute information of the object. The syntax format is as follows:访问权限修饰符 属性名称 = 属性值;
<?php
class Students{
var $name;
public $age;
private $sex;
public static $school;
}
?>Member methods
Functions defined in a class are called member methods. The only difference between functions and member methods is that functions implement an independent function, while member methods implement a behavior in the class and are part of the class. You can declare multiple member methods in a class. The declaration of member methods is exactly the same as the declaration of functions. However, when declaring member methods, you can add some access modifiers in front of the function keyword to control access. Permissions, such as public, private, protected, etc. Another thing to note is that the declared member methods must be related to the class and cannot be some meaningless operations. For example, when declaring the student class, if you declare the "flying" member method, every student instantiated can fly. This is a design error. [Example] Create some member methods in the Students class created in the above example.<?php
class Students{
var $name;
public $age;
private $sex;
public static $school;
public function Write(){
}
protected static function Read(){
}
function Listen(){
}
}
?>[权限修饰符] function 方法名 (类型 参数1, 类型 参数2, ..., 类型 参数n) : 返回值类型 {
... ...
}<?php
class Students{
var $name;
public $age;
private $sex;
public static $school;
public function Write(string $a, int $b):bool{
}
protected static function Read(string $str):int{
}
function Listen(int $num):bool{
}
}
?>Instantiate the object and access the members in the object
变量名 = new 类名(参数); //实例化一个类 变量名 -> 成员属性 = 值; //为成员属性赋值 变量名 -> 成员属性; //直接获取成员属性的值 变量名 -> 成员方法(); //访问对象中的成员方法
下面通过一个示例来演示一下：
<?php
header("Content-type:text/html;charset=utf-8");
class Website{
public $name, $url, $title;
public function demo(){
echo '成员方法 demo()';
}
}
$student = new Website();
$student -> name = 'php中文网';
$student -> url = '//m.sbmmt.com/';
$student -> title = '实例化对象';
echo $student -> name.'<br>';
echo $student -> url.'<br>';
echo $student -> title.'<br>';
$student -> demo();
?>
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