Analyze the specific usage of PHP5 destructor_PHP tutorial-PHP Tutorial-php.cn

Analyze the specific usage of PHP5 destructor_PHP tutorial

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Release： 2016-07-15 13:29:11

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In the upgraded version of in PHP5, __construct() is used to name the constructor instead of having the same name as the class. The advantage of this is that the constructor can be made independent of Class name, when the class name changes, there is no need to modify the name of the constructor accordingly.

Contrary to the constructor, in PHP5, you can define a function named __destruct(), called the PHP5 destructor. PHP will call the destructor before the object is destroyed in memory. Let the object do some work before disappearing completely. Object destruction can generally be achieved by assigning a value to null.

<ol class="dp-xml">
<li class="alt">
<span><strong><font color="#006699"><span class="tag"><?</SPAN><SPAN class=tag-name>php</SPAN></FONT></STRONG><SPAN> </SPAN></SPAN><LI class=""><SPAN>/*  </SPAN><LI class=alt><SPAN> * Created on 2009-11-18  </SPAN><LI class=""><SPAN> *  </SPAN><LI class=alt><SPAN> * To change the template for this generated file go to  </SPAN><LI class=""><SPAN> * Window - Preferences - PHPeclipse - PHP - Code Templates  </SPAN><LI class=alt><SPAN> */  </SPAN><LI class=""><SPAN> class student{  </SPAN><LI class=alt><SPAN>  //属性  </SPAN><LI class=""><SPAN>  private $no;  </SPAN><LI class=alt><SPAN>  private $name;  </SPAN><LI class=""><SPAN>  private $gender;  </SPAN><LI class=alt><SPAN>  private $age;  </SPAN><LI class=""><SPAN>    </SPAN><LI class=alt><SPAN>  private static $</SPAN><SPAN class=attribute><FONT color=#ff0000>count</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>0</FONT></SPAN><SPAN>;  </SPAN></SPAN><LI class=""><SPAN>  function __construct($pname)  </SPAN><LI class=alt><SPAN>  {  </SPAN><LI class=""><SPAN>   $this-</SPAN><SPAN class=tag><STRONG><FONT color=#006699>></span></font></strong></span><span class="attribute"><font color="#ff0000">name</font></span><span> = $pname;  </span>
</li>
<li class="alt"><span>   self::$count++;  </span></li>
<li class=""><span>  }  </span></li>
<li class="alt"><span>    </span></li>
<li class=""><span>  function __destruct()  </span></li>
<li class="alt"><span>  {  </span></li>
<li class=""><span>   self::$count--;  </span></li>
<li class="alt"><span>  }  </span></li>
<li class=""><span>    </span></li>
<li class="alt"><span>  static function get_count()  </span></li>
<li class=""><span>  {  </span></li>
<li class="alt"><span>   return self::$count;  </span></li>
<li class=""><span>  }  </span></li>
<li class="alt"><span> }  </span></li>
<li class=""><span>   </span></li>
<li class="alt">
<span> $</span><span class="attribute"><font color="#ff0000">s1</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">new</font></span><span> student("Tom");  </span>
</li>
<li class=""><span> print(student::get_count());  </span></li>
<li class="alt"><span>   </span></li>
<li class="">
<span> $</span><span class="attribute"><font color="#ff0000">s2</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">new</font></span><span> student("jerry");  </span>
</li>
<li class="alt"><span> print(student::get_count());  </span></li>
<li class=""><span>   </span></li>
<li class="alt">
<span> $</span><span class="attribute"><font color="#ff0000">s1</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">NULL</font></span><span>;  </span>
</li>
<li class=""><span> print(student::get_count());  </span></li>
<li class="alt"><span>   </span></li>
<li class="">
<span> $</span><span class="attribute"><font color="#ff0000">s2</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">NULL</font></span><span>;  </span>
</li>
<li class="alt"><span> print(student::get_count());  </span></li>
<li class="">
<span></span><span class="tag"><strong><font color="#006699">?></font></strong></span><span> </span>
</li>
</ol>

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The above code is the specific method of using the PHP5 destructor. I hope it will be helpful to everyone.