Are setter methods needed when constructor sets properties?

[jeddiki]

Hi,
I have just started learning OOP
and have a couple of questions.

Is it correct to say that if I write a constructor method for my class
then I will not need to use he set method to add values to properties ?

i.e. with this:

<?php
class person {
  var $name;
  var $sp_number; 
      public $height;
      protected $social_insurance;
 
function __construct($persons_name) {
    $this->name = $persons_name;
  }
 
function get_name() {
    return $this->name;
  }
 
} // end class
?>
 

this will not be needed:

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

because in my html I will use this:

<?php
$stefan = new person("Stefan Mischook");             
 
echo "Stefan's full name: " . $stefan->get_name()."<br>";
?>

True - or have I got things mixed up ?

[Markus]

@jeddiki
You may later want to change the person's name. Maybe he/she gets married and take's the other person's name? Should always have getter and setter methods, I believe.

Also, could you please read your Personal Messages.

Thanks,
Markus.

[jeddiki]

Following on from that question is another
basic newbie one:

Again using this class:

class_lib.php

class person {
  var $name;
  var $sp_number; 
  public $height;
  protected $social_insurance;
 
 
  function __construct($persons_name) {
    $this->name = $persons_name;
  }
 
 
  function set_name($new_name) {  
   $this->name = $new_name;            
  }
 
  function get_name() {
    return $this->name;
  }
 
} // end class
 

To apply values to the name property I use this:

<?php
$stefan = new person("Stefan Mischook");
?>

How do I add a value to the $sp_number ?

I guess that I can not use the constructor again
so do I add this to class_lib.php ?

  function set_sp_number($new_sp_number) {  
   $this->sp_number = $new_sp_number;            
  }
 

and then use it like this ?

$stefan->set_sp_number(8872);

Any explaination would be greatly appreciated :)

[Markus]

You can pass multiple arguments to a method.

 
class Example
{
 
    public $firstName;
    public $lastName;
 
    // Constructor
    function Example($first, $last)
    {
        $this->firstName = $first;
        $this->lastName = $last;
    }
 
}
 
$ex = new Example("John", "Dorian");
 
 

[jeddiki]

Thats fine but what if I need to add the $lastName at a
later date ( eg when they fill out a profile form).

How do I add the $lastName then - I guess a should not
use :

$ex = new Example( , "Dorian");

or could I ?

[Markus]

You can set default values for arguments on methods. So you can provide either a first name and a last name, or just a first name.

function Example($first, $last = "")
{
    ....
}
 

And you could set the last name later, with a setter method.

$ex->set_lastName("Dorian");
 

You don't call your constructor after you have initialised the class, i.e after you have done $ex = new Example().

[Dormilich]

@jeddiki
correct, PHP will throw an error in this case.

to add the name either use the setter method or set the property directly, if it is defined public.

$ex->lastName = "Dorian";

note: the var keyword is not encouraged in PHP 5, it is simply kept for compatibility reasons towards PHP 4

[jeddiki]

Do you mean the var that I put in my class_lib.php ?

<?php
 
class person {
  var $name;
    var $sp_number; 
      public $height;
      protected $social_insurance;
 

If so how should I be writing it in that class definition ?

BTW I am reading through the PHP 5 Power Programming by Andi Gutmans
so hopefully I'll get better at this ;)

[Dormilich]

@jeddiki
a) yes

b) that depends on the usage, possible values

• public (external read/write access)
• protected (internal access across inheritance)
• private (access only inside the defining class)

static, const and read-only are covered later

[Markus]

You should declare variables as protected, private or public (usually).

So don't use the 'var' keyword, but any of the above. It's not going to give you any trouble, though.


-_- nvm.