__construct使用的函数是什么？ [英] What is the function __construct used for?

问题描述

我一直注意到 __ construct 很多类。我做了一些阅读和网上冲浪，但我找不到一个解释，我可以理解。我刚刚开始与OOP。

我想知道是否有人可以给我一个一般的想法是什么，然后一个简单的例子，如何使用PHP ？

解决方案

__construct是PHP5中引入的，它是定义你的构造函数的正确方法你使用类的名称为构造函数）。
你不需要在你的类中定义一个构造函数，但是如果你想传递任何参数对象构造，那么你需要一个。

这样：

 类数据库{
 protected $ userName; 
 protected $ password; 
 protected $ dbName; 
 
 public function __construct（$ UserName，$ Password，$ DbName）{
 $ this-> userName = $ UserName; 
 $ this-> password = $ Password; 
 $ this-> dbName = $ DbName; 
} 
} 
 
 //你可以这样使用：
 $ db = new Database（'user_name'，'password'，'database_name'）;所有其他都在PHP手册中解释：点击这里 
 
I have been noticing __construct a lot with classes. I did a little reading and surfing the web, but I couldn't find an explanation I could understand. I am just beginning with OOP.

I was wondering if someone could give me a general idea of what it is, and then a simple example of how it is used with PHP?
解决方案
The "__construct" was introduced in PHP5 and it is the right way to define your, well, constructors (in PHP4 you used the name of the class for a constructor).
You are not required to define a constructor in your class, but if you wish to pass any parameters on object construction then you need one.

An example could go like this:
class Database {
  protected $userName;
  protected $password;
  protected $dbName;

  public function __construct ( $UserName, $Password, $DbName ) {
    $this->userName = $UserName;
    $this->password = $Password;
    $this->dbName = $DbName;
  }
}

// and you would use this as:
$db = new Database ( 'user_name', 'password', 'database_name' );
Everything else is explained in the PHP manual: click here

                        
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