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PHP 5 Tutorial - Not Pure Object Oriented Programming Approach

PHP development team has come up with great improvement in PHP5, one such feature is the introduction of improved Object Oriented Concept in PHP5, But it lacks the pure Object Oriented Programming approach. In this article i will be discussing few bugs that exists in the OOPS implementation in PHP5 and the main culprit behind this bugs are:





Loosely typed behavior of PHP Language
This will the major problem that PHP programmer will face while migrating to PHP5 from PHP4. In Object Oriented Programming the data members that the class is going to use should be defined before defining the constructors and methods for the class. But due to the loosely typed behavior of PHP5 following bugs exists for loosely typed behaviour.

Automatically creates variables for class while assigning values to it
Now if you are accessing an undefined class variable, PHP5 does not throws an error instead it automatically creates that undefined variable.
Example:

< ?
class employee
{
 public function setName($name)
 {
    $this->name = $name;    //Automatically creates $name variable for employee class
 }
 public function getName()
 {
     return $this->name;
 }
}
$employee = new employee();
$employee->setName("Hitesh");
echo $employee->getName();
echo "<br />".$employee->name;
?>

Output:
Hitesh
Hitesh
Explanation: When the above code snippet is executed $name is automatically created inside setName() method.
Example:

< ?
class employee
{
    public function __construct()
    {
	echo "Constructor Called!!!";
    }
}
$employee = new employee("Hitesh");    //Should should throw an error as the constructor does not any argument defined
?>

Output:
Constructor Called!!!
Explanation: Here i am instantiating class object and passing 1 parameter “Hitesh”, but in the __construct function i have not defined any parameter but still PHP5 accepts it.

Function Overloading not Supported
One the main feature of Polymorphism in Object Oriented Language is Function Overloading but unfortunately PHP5 does not supports it.
Function Overloading is the technique wherein class can have more than one method with same name but the parameters differ by the parameter count, type and position.
Example - Function OverLoading Usage

< ?
public function setName($name)
{
 
}
 
public function setName($fname,$lname)
{
 
}
?>

Example - Using Function Overloading in PHP5

< ?
class employee
{
    private $name;
    private $fname;
    private $lname;
    public function setName($name)   
    {
	$this->name = $name;
    }
 
    public function setName($fname,$lname)    //Method setName redeclared again
    {
	$this->fname = $fname;
	$this->lname = $lname;
    }
}
$employee = new employee("Hitesh");
?>

Output:
Cannot redeclare employee::setName()
Explanation: In the above snippet i have declared two methods setName() but as PHP5 does not supports Function Overloading the PHP5 throws an error.

Related Post

• Database Class in PHP5
• Singleton Class in PHP 5
• Exploring Magic Methods in PHP 5
• PHP 5 Tutorial - __clone Magic Method
• PHP 5 Tutorial - __toString() Magic Method

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