How to Invoke Child Class Functions from Parent Class Using Abstract Classes in PHP?

Utilizing Abstract Classes to Invoke Child Class Functions from Parent Class in PHP

In the realm of object-oriented programming, there often arises a need to access functions defined in child classes from within the parent class. Let us examine how this can be achieved in PHP.

Consider the following scenario: A parent class named "whale" has a function called "myfunc()". However, the intention is to call a function named "test()" from the child class "fish", which extends the "whale" class. How can this be accomplished?

The answer lies in the concept of abstract classes. Abstract classes serve as placeholders, mandating that inheriting classes must implement certain functions. Here's how it can be applied in PHP:

<code class="php">abstract class whale
{
  function __construct()
  {
    // some code here
  }

  function myfunc()
  {
    $this->test(); // Calling the abstract function from the parent class
  }

  abstract function test(); // Abstract function declaration
}

class fish extends whale
{
  function __construct()
  {
    parent::__construct();
  }

  function test()
  {
    echo "So you managed to call me !!";
  }
}

$fish = new fish();
$fish->test();
$fish->myfunc();</code>

By introducing the abstract "whale" class, we declare that inheriting classes must implement the "test()" function. This ensures that the "fish" class has a definition for "test()". Subsequently, we can successfully invoke "test()" from within the "myfunc()" function of the parent class.

Remember, defining a function as abstract implies that the inheriting class must provide its implementation. If the child class fails to do so, it will result in a PHP error.

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