how to change non static variable to static method in php

Question

I am calling constant variable like this, but it show errors, How to solve this? I don't calling it like these code below,

$b = new A()
$b::$test

here my code

class A {
   const test = 4;
}

class B {

  private $a = null;
  public function __construct(){
      $this->$a = new A();
  }

  public function show(){
     echo $this->$a::test;
  }

}

$b = new B();
$b->show();

How to calling static variable test in class A? Thanks in advance

Answer 1

Every thing is fine except $this->$a::test; and $this->$a = new A();. You have to use property without $ sign like below

class A {
   const test = 4;
}

class B {

  private $a = null;

  public function __construct()
  {
      $this->a = new A();
  }

  public function show()
  {
     echo $this->a::test;
  }
}

$b = new B();
$b->show();