Inheritance in php

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Inheritance is the property through which a subclass inherits the feature or property of its super class. It is also known as parent child class relationship.

In PHP inheritance is done with the help of extends keyword.

Example of Inheritance in PHP.

<?php

  class A
   { 
    public $i;
    function display() 
    {
     echo "base class=$this->i";
     }
   }
   
class B extends A // how B class inherits class A.
{
public $j;
function show()
{
echo "<br>subclass i=$this->i";
echo "<br>subclass j=$this->j";
}
}

 $a1= new A();
 $a1->i=100; // how to call properties or variable of a php class
 $a1->display();
 $b1= new B();
 $b1->i=200;
 $b1->j=400; 
 $b1->show(); 
?>

Output of the above program is as follows

Complete Example of Inheritance in PHP with constructor example

<?php
  class Person
   { 
    public $name;
     function __construct($n) //default constructor
    {
           $this->name=$n;
    }
    function display() //default function with no arguement.
    {
     echo "Person Details <br> Name:= $this->name" ;
     }
   }

   class Student extends Person
   {
    public $rollNo;
    function __construct($n,$r)  
    {
     $this->name=$n;
     $this->rollNo=$r;
    }
   function print()
   {
    echo "<br>Student Details :<br>name= $this->name";
    echo "<br> rollNo= $this->rollNo";
  }
 }
$p1= new person('tom');
$p1->display();
$s1= new Student('john',4563);
$s1->print();
?>

Output of the above program is as follows

Final class to prevent inheritance

<?php
 final class A
   { 
    
   }

class B extends A
{
}
?>

above program output resulted in error as final class can not be inherited.

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Inheritance in php

Example of Inheritance in PHP.

Complete Example of Inheritance in PHP with constructor example

Final class to prevent inheritance

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