Why to assign into constructor ?

[Rommeo]

I was reading a tutorial about OOP, and there is something makes me confused. Here is the code :

<?php
class person { 
    public $name;
    public $age; 

    public function __construct() 
       { 
        $this->name = "mr smith";
        $this->age = 0;
       }
    public function blabla etc..  
}
?>

I know what the constructor is for.. But we could code this class like this :

<?php
class person { 
    public $name = "mr smith";
    public $age = 0; 
    
    public function blabla.. etc.
}
?>

So my question is :why he assigned the variables like in the first example, we can code it like the second example though. What's the benefit of the first one ?

[AviNahum]

<?php
class person { 
    public $name;
    public $age; 

    public function __construct($n, $g) 
       { 
        $this->name = $n;
        $this->age = $g;
       }
}

$a = new person("my name" , "my age");

?>

 

it would nicer to work this way, right?

[mikesta707]

for your example, yeah it doesn't really matter. However, that is a tutorial, and it really is just showing you the syntax of how constructors go, and not really trying to convince you that you should always assign variables in your constructor.

 

by the way, you can also make a constructor this way

class foo{

//below is the constructor
public function foo($msg){
echo $msg;
}
}

 

now if you were to create the function like so

 

$foo = new foo("Hello World!");

 

it would output

Hello World!

 

kind of off topic, but yeah

[Rommeo]

I see, so assigning the values in constructor or in decleration part does not make any difference..?

[RussellReal]

a constructor is just the function to trigger when the object is instantiated.. whether you specify it in the class or in a method inside the class, it will still do the same thing, however, there is an exception to this.. if you make the variable declared within the class not within the method static than you can access it like this:

 

foo::$variable;

 

but that is mostly for outside use as its more strict with static values.

[mikesta707]

it depends on your situation. if you want the constructor to assign variables that you define, IE

class foo{
var $value;
public function foo($value){
$this->value = $value;
}
}

However, if whenever you instantiate the class, the variable will always have the same value, then assigning it in the declaration part and the constructor basically do the same thing

[RussellReal]

mike.. please re-read your posts before you submit.. or atleast preview them, look @ your code here lol and the last post you posted on.. the eval() demo.. there is a syntax error.. its not a race

[mikesta707]

oh my bad, had to hurry to class so I was a bit rushed... but its just a missing semi colon and an extra $ symbol... its not that bad...

 

everyone makes mistakes dude...

[KevinM1]

To the OP, imagine you're creating your Person objects from data stored in the database... how likely is it that all of those people will be named Mr. Smith?

[Rommeo]

To the OP, imagine you're creating your Person objects from data stored in the database... how likely is it that all of those people will be named Mr. Smith?

i just wanted to show the usage of both decleration.

let me change the example ;

<?php
class brand { 
    public $name;
    public $size; 

    public function __construct() 
       { 
        $this->name = "not available";
        $this->size = 5;
       }
    public function blabla etc..  
}
?>

[Rommeo]

Thank you for your explanations guys.. (:  Now I get it

[RussellReal]

To the OP, imagine you're creating your Person objects from data stored in the database... how likely is it that all of those people will be named Mr. Smith?

 

everybody with a black suit! if this was the matrix that is.

[KevinM1]

To the OP, imagine you're creating your Person objects from data stored in the database... how likely is it that all of those people will be named Mr. Smith?

 

everybody with a black suit! if this was the matrix that is.

 

Hello, Mr. Anderson....