What is Abstract (base) class in PHP OOP's?

Question

Do u know about planning or implementing OOP methdology access to array methods in PHP in future. Like show code later:

$a = new Array();
$a->append("hello");
$a->shift();
$p = $a->pop();

$b = Array::fill(fill_char="*", count=20);
$b->pop();

Answer 1

The abstract classes and methods are used to create a model of minimum required methods which must be defined in normal sub-classes derived from an abstract class (with extends).
An abstract class is created with the abstract keyword.
An abstract class cannot be instantiated, can only be inherited by other sub-classes extended from it.

The abstract methods are declared with the abstract keyword, and cannot have an implementation, they simply declare the method's signature.

abstract public function methodName($arguments);

Abstract methods are only created in an abstract class.

• Example:
  In this example is created an abstract class with a property ($name), an abstract method ( greetName() ) and a normal method ( setName() ).

  <?php
  // AbstractClass class
  abstract class AbstractClass {
  protected $name;

  // declare an abstract method
  abstract public function greetName($greet);

  // define a normal method
  public function setName($name) {
  $this->name = $name; // sets the value of $name property
  }
  }
  ?>