Inheritance not working in PHP

Question

0.00/5 (No votes)

See more:

Hello friends. I am new to PHP. I'm trying inheritance in PHP but I'm not able to understand some concepts. When I am calling print_name method from child class nothing gets printed. Can anyone tell me where I am going wrong?

PHP

class Parent_class
{
    var $first_name="David";
    var $last_name="Hussey";
    
    function __construct()
    {
        echo "Parent class object instantiated" . "</br>";
    }
    
    function print_name($name,$surname)
    {
        $this->first_name=$name;
        $this->last_name=$surname;
        
        echo $this->first_name . " ". $this->last_name . "</br>";    
    }
}
    
class Child_class extends Parent_class
{
    var $x="Roger";
    var $y="Nadal";
    
    function __construct()
    {
        echo "Child class object instantiated" . "</br>";
    }
    
    function call_parent_class_function()
    {
        echo $this->x . " ". $this->last_name . "</br>";
        $this->print_name($x,$y);
    }
}

$obj = new Child_class;
$obj->call_parent_class_function();

$obj1 = new Parent_class;
$obj1->print_name("Virat","Kohli");

Posted 6-Feb-14 1:56am

Pritam N. Bohra

Updated 6-Feb-14 2:07am

Maarten Kools

v4

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Peter Leow · Accepted Answer · 2014-02-06T02:18:00

Solution 1

1. Missing

PHP

<?php

at the beginning and

PHP

?>

at the end
2.

PHP

function call_parent_class_function()
{
    echo $this->x . " ". $this->last_name . "</br>";
    //$this->print_name($x,$y);
    $this->print_name($this->x,$this->y);
}

Posted 6-Feb-14 2:18am

Peter Leow

Updated 6-Feb-14 2:19am

v2

Comments

Pritam N. Bohra 6-Feb-14 8:30am

I already added but in the question i just wrote the main part of the program

Peter Leow 6-Feb-14 8:43am

Look at the change in number 2. It should work now. Remember to accept this solution.

Pritam N. Bohra 6-Feb-14 10:45am

That solution worked very well. Thank you. I would like to ask one more question. When the child class object is created, the default constructor is called automatically, which in turn calls the parent class constructor. but i my case only the child class constructor's print statement get printed. It should print parent class constructor's print statement as well. Am I correct?

Peter Leow 6-Feb-14 19:44pm

Carry out experiment with the following 2 scenario separately and see for yourself:
1. Add parent::__construct(); in the child constructor
2. Comment out the child constructor

Pritam N. Bohra 7-Feb-14 7:20am

Thank you that worked. I thought it would call the parent class constructor automatically

Peter Leow 7-Feb-14 8:13am

1. If the child class defines a constructor, its parent constructors are not called implicitly, you have to make a call to parent::__construct() within the child constructor.
2. If the child does not define a constructor then it will call the parent class constructor implicitly if it is not declared as private.