PHP Object-oriented constructor description

This article does not repeat the object-oriented knowledge, this article focuses on the PHP constructor.
The constructor of a PHP class can be a magic cube __construct () or a function with the same name as the class, as in the following example:

classA{publicfunctionA(){echo'A is constructing...';    }  classB{publicfunction__construct(){echo'B is contructing...';    $anew A();   // A is constructing...$bnew B();   // B is constructing...

In addition, when inheriting, it should be noted that:
" subclasses can not write constructors, then use the constructor of the parent class "

    class   A  {  protected      $name ;  Public    function   A   ()  {  echo   ' A is constructing ...    
 ' ;  public    function   set_name   ( $name )  {     $this ->name =  $name ;  public    function   get_name   ()  {  return      $this ->name; }}   class   B   extends   A  { /* Public Function __ Construct () {echo ' B is contructing ...    
 '; } */} //$a = new A ();    $b  =  new  b (); //A is constructing ...   $b ->set_name ( ' Zhangsan ' );  Echo   $b ->get_name ();  

" if the subclass writes a constructor, the constructor for the parent class is no longer called "

 classA{protected$name; Public functionA(){Echo' A is constructing ...
'; } Public functionset_name($name){$this->name =$name; } Public functionget_name(){return$this->name; } } classBextendsA{ Public function__construct(){Echo' B is contructing ...
'; } }//$a = new A ();$b=NewB ();//Just echo ' B is contructing ... '$b->set_name (' Zhangsan ');Echo$b->get_name ();//Zhangsan

" if the constructor of the parent class is private, it can be inherited, but the subclass must have its own constructor and explicitly write "

 classA{protected$name;Private functionA(){Echo' A is constructing ...
'; } Public functionset_name($name){$this->name =$name; } Public functionget_name(){return$this->name; } } classBextendsA{ Public function__construct(){Echo' B is contructing ...
'; } }//$a = new A ();$b=NewB ();//B is contructing ...$b->set_name (' Zhangsan ');Echo$b->get_name ();//Zhangsan

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