Question

I’m working through this tutorial:
http://www.killerphp.com/tutorials/object-oriented-php/php-objects-page-3.php

At first he has you create a setter and getter method in the class:

<?php

class person{
    var $name;      

    function set_name($new_name){
        $this->name=$new_name;
    }

    function get_name(){
        return $this->name;
    }
}

php?>

And then you create the object and echo the results:

<?php 
    $stefan = new person();
    $jimmy  = new person();

    $stefan ->set_name("Stefan Mischook");
    $jimmy  ->set_name("Nick Waddles");

    echo "The first Object name is: ".$stefan->get_name();
    echo "The second Object name is: ".$jimmy->get_name();

?>

Works as expected, and I understand.

Then he introduces constructors:

class person{
    var $name;

    function __construct($persons_name) {       
        $this->name = $persons_name;        
    }       

    function set_name($new_name){
        $this->name=$new_name;
    }

    function get_name(){
        return $this->name;
    }
}

And returns like so:

<?php 

    $joel   = new person("Joel");

    echo "The third Object name is: ".$joel->get_name();
?>

This is all fine and makes sense.

Then I tried to combine the two and got an error, so I’m curious-is a constructor always taking the place of a “get” function? If you have a constructor, do you always need to include an argument when creating an object?

Gives errors:

<?php 
    $stefan = new person();
    $jimmy  = new person();
    $joel   = new person("Joel Laviolette");
    $stefan ->set_name("Stefan Mischook");
    $jimmy  ->set_name("Nick Waddles");

    echo "The first Object name is: ".$stefan->get_name();
    echo "The second Object name is: ".$jimmy->get_name();
    echo "The third Object name is: ".$joel->get_name();
?>

Answer 1

It’s giving you errors because the constructor has required parameters. To make a parameter optional give it a default value like this

function __construct($persons_name=null) {
    if ($persons_name) {
        $this->set_name($persons_name);//use the setter in the constructor.
    }      
}

this will now work

$stefan = new person();
$stefan ->set_name("Stefan Mischook");
$joel   = new person("Joel Laviolette");
echo "The first Object name is: ".$stefan->get_name();
echo "The second Object name is: ".$joel->get_name();