In PHP, we can create an abstract class by using an abstract keyword. When we create an abstract class then there are some rules.

• An abstract class contains at least one abstract method.
• An abstract method is defined but not used or not implemented.
• The number of required arguments must be the same.
• We cannot create an object of an abstract class.

 

Example1 ( Simple class )

<?php
class car{
    public $name;
    public function __construct($name){
       echo $this->name=$name;
    }
}
$obj= new car("Audi");
?>

Output

Audi

 

Example2 ( abstract class )

<?php
abstract class car{
    public $name;
    public function __construct($name){
       echo $this->name=$name;
    }
}
$obj= new car("Audi");
?>

Output

Note: we cannot create an object of an abstract class.

Let’s see another example where abstract class A is created and at least one abstract show()  method is declared but not implemented.

It is implemented in the child class, not the parent class.

 

Example 3

Example 4

<?php

// Parent class
abstract class Fruit {
public $name;
 public function __construct($name) {
        $this->name = $name;
}
abstract public function intro() : string;
}

// Child classes
class Apple extends Fruit {
  public function intro() : string {
    return "I like $this->name!";
  }
}

class Banana extends Fruit {
 public function intro() : string {
    return "I like $this->name!";
  }
}

class Grapes extends Fruit {
public function intro() : string {
    return "I like $this->name!";
  }
}

// Create objects from the child classes
$obj1 = new Apple("Apple");
echo $obj1->intro();
echo "<br>";

$obj2= new Banana("Banana");
echo $obj2->intro();
echo "<br>";
$obj3 = new Grapes("Grapes");
echo $obj3->intro();
?>

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