PHP notes: A detailed explanation of Object oriented Design

public represents the global, which can be accessed by both internal and external subclasses.

<?php

     class Test{
         public  $name='Janking',
                 $sex='male',
                 $age=23;

         function __construct(){
             echo $this->age.'<br />'.$this->name.'<br />'.$this->sex.'<br />';
         }

          function func(){
             echo $this->age.'<br />'.$this->name.'<br />'.$this->sex.'<br />';
         }
     }

 
 $P=new Test();
 echo '<br /><br />';
 $P->age=100;
 $P->name="Rainy";
 $P->sex="female";
 $P->func();
 ?> 
Public

private is private and can only be used within this class;

<?php

     class Test{
         private  $name='Janking',
                 $sex='male',
                 $age=23;

         function __construct(){
             $this->funcOne();
         }

          function func(){
             echo $this->age.'<br />'.$this->name.'<br />'.$this->sex.'<br />';
         }

         private function funcOne(){
             echo $this->age.'<br />'.$this->name.'<br />'.$this->sex.'<br />';
         }
     }

 
 $P=new Test();
 echo '<br /><br />';
 $P->func();
 $P->age=100;        // Cannot access private property Test::$age 
 $P->name="Rainy";   // Cannot access private property Test::$name 
 $P->sex="female";   // Cannot access private property Test::$female
 $P->funcOne();      // Call to private method Test::funcOne() from context ''
 ?> 
Private

protected represents protected, accessible only in this class or subclass or superclass; Magic methods related to encapsulation:

___ () : Is the method that is automatically called when the private member property value is set directly

Succget () : Is the method that is automatically called when you get the value of the private member property directly

__isset (); This method is called automatically when isset checks to see if a private property in an object is saved

__unset (); Is called automatically when unset directly deletes a private property in an object