tp5 variable calling problem in different controllers

Question

Assume there is an A controller and a B controller. How can the variables defined in the A controller be called by the B controller after being assigned by the function of the A controller? I've tried using global variables, but it doesn't work either. Please give me an answer!

Answer 1

Inheritance of controller class

Answer 2

Let controller B inherit controller A

class A {
    public $a;
    public function __construct() {
        $this->a = 1;
    }
}

class B extends A {
    public function fb() {
        echo $this->a;
    }
}