About PHP (vii) object-oriented programming

Last Update:2014-08-11 Source: Internet

Author: User

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Declaration and object initialization of a class1.1 When declaring a member property in a class: there must be a modifier in front of it, use var when you don't know what to use, and if you know the Modifier keyword , you don't use var.var $color; var $name = "zhangsan" 1.2 A file holds only one class , and the file name contains the class name , such as : Class Name. class.phpperson.class.php 1.3 Create an object with the new keyword, create an object to allocate a space in memory $ object reference = new Class name;$person = new Person<pre code_snippet_id="447325" snippet_file_name="blog_20140810_1_8140551" name="code" class="java"><pre code_snippet_id="447325" snippet_file_name="blog_20140810_1_8140551" name="code" class="java"><?phpclass person {var $name; Java:private String Name;var $age; var $sex; function say () {echo $this->name;}} $p 1 = new person; Java:person person = new person, $p 1->name = "lisi"; Java:person.name = "lisi"; $p 1->say (); Java:person.say ();? ></pre></pre>1.4the allocation of objects in memoryA. Stack memory: store local variablesB. Heap memory: storing objectsC. Shared area: storing static variablesD. Code snippet: storage method, etc. second, the constructor function and the destructor2.1 Constructors:A. Construction method is the first method that is automatically called after object creation is completedB. in PHP4, the method with the same name as the class is the construction methodC. In PHP5, the method of construction is chosen using the Magic method __construct (), which is used in all classes to declare the constructor method using this namePros: the construction method does not change when changing the class nameD. How the constructor Works: class for member properties<pre code_snippet_id="447325" snippet_file_name="blog_20140810_2_9853201" name="code" class="php"><pre code_snippet_id="447325" snippet_file_name="blog_20140810_2_9853201" name="code" class="php"><?phpclass person {var $name, var $age, var $sex, function __construct ($name = "", $age =0, $sex = "male") {$this->name=$ Name: $this->age= $age; $this->sex= $sex;} Function say () {echo ' My name: {$this->name}, my age: {$this->age}, my gender: {$this->sex}. ";}} $p 1=new person ("zhangsan", 20, "female"), $p 2=new person ("lisi"), $p 3=new person ("wangwu"); $p 1->say (); $p 2->say (); $p 3->say ();? ></pre></pre> 2.2 destructors:A. A destructor is the last method that is called automatically before the object is releasedB. Like java, PHP frees up resources using the garbage collector, except that it is recycled immediately after PHP calls, while Java is Not.C. Function of Destructors: Close some resources, do some cleanup work, use magic method __destruct ()<pre code_snippet_id="447325" snippet_file_name="blog_20140810_3_9961885" name="code" class="php"><pre code_snippet_id="447325" snippet_file_name="blog_20140810_3_9961885" name="code" class="php"><?phpclass person {var $name, var $age, var $sex, function __construct ($name = "", $age =0, $sex = "male") {$this->name=$ Name: $this->age= $age; $this->sex= $sex;} Function say () {echo ' My name: {$this->name}, my age: {$this->age}, my gender: {$this->sex}. ";} function __destruct () {echo $this->name. " Good bye! ";}} $p 1=new person ("zhangsan", 20, "female"), $p 1->say (); $p 1 = null;//my name: zhangsan, my age: 20, my sex: female. ///zhangsan goodbye!?></pre></pre> 2.3 Magic MethodsThe Magic method is the system gives us a good, at different times to complete a function and automatic call method, different magic methods have different call timingMagic method begins with ____construct (); constructor function __destruct (); Destructors __set (); __get (); __isset (); __unset (); __clone (); __call (); __sleep (); __weakup (); __tostring () __autoload ();

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