如何在同一个父级的另一个子级 class 中访问子级 class 的成员函数

Question

I've three classes lets say Class A , Class B and Class C .

Class A is parent class and class B and C are its child.

There is function in class B, I want to access that function in class C without inheriting Class C with B. Is it possible?

public class A {


}

class B extends A{

      public function hello (){
        return "Hello world";
      }
}

public class C extends A{

    public function world (){
        $this->hello();
    } 

} 

Answer 1

To expand upon @u_mulder's comment: it's indeed not possible, because though B and C both derive from the same class A, they are distinct classes, in the same way that a bicycle and a car are both vehicles. When using a bicycle you cannot assume to use functions from a car, simply because they're both vehicles.

The question you'd need to answer yourself is what is the functionality of the method I need in class B ? Is it specific to class B ? Or is it something all entities which are class A ? Or different yet, is it a separately functionality altogether but which only class B needs to consume? The solution to the first case would be to move the function to class B . In the second case you'd move the function to class A. In the third case you'd implement the function in a separate class and inject that into class B .

I recommend you read up on SOLID principles and other principles of OOP design