php OOP class variables vs object variables

Question

when making a class in php what is the difference between these two :

class Search 

    function __construct()
    {

        $this->variable1= 1234;      

    }
}

and

class Search 

    private $variable1;

$variable1=1234;

    function __construct()
    {

    }
}

if i need to access a value across different methods does it make any difference which approach i chose?

thank you

Answer 1

The difference between object and class variables is how you can access them.

• object variable: $obj->var
• class variable: class::$var

Your class definition should be:

class Search {
    static $variable = 2;   // only accessible as Search::$variable
}

Versus:

class Search2 {
    var $variable = "object_prop";
}

Wether you use var or public or the private access modifier is not what makes a variable an object property. The deciding factor is that it's not declared static, because that would make it accessible as class variable only.

Answer 2

The are essentially the same thing however if you do not declare the variable/property before it is called you will get a warning saying the variable doesn't exist.

It is best practice to do it this way:

class Search {

  private $_variable1;

  function __construct() {
    $this->_variable1=1234;
  }

}

Note: private variables are only available to the class they are declared in.