PHP4 vs PHP5 | Difference between PHP4 and PHP5

PHP - Hypertext Preprocessor

PHP	Hypertext Preprocessor
Developer	Rasmus Ledorf
Year	1994

PHP, Hypertext Preprocessor , The Open Source Language which is trend in the 20th century for creating fast and dynamic web pages. This the Server Side Scripting Language, with a powerful tool for creating web pages. Lets see the revision of PHP version 4 and 5.

PHP4 vs PHP5 (Additional Features of PHP5)

Constructors and Destructors

• In PHP4, Constructor have same name as the Class name.
• In PHP5, name Constructors as _construct and Destructors as _destruct().

Passed by References

• In PHP4, everything was passed by value.
• In PHP5, all objects are passed by references.

Abstract

• In PHP5, we can declare a class as abstract.

Static Methods and Properties

• In PHP5, Static Methods and Properties are also available. When you declare a class as static, then you can access using :: operator without creating an instances of class

_autoload()

• PHP5 introduces a special function called _autoload().

Final

• PHP5 allows you to declare a class or method as final.

Magic Methods

• PHP5 introduces magic methods such as _call, _get, _set and _tostring

Visibility

PHP5 has 3 level of visibilities
• Public: methods are accessible to everyone including objects outside the class
• Private: methods are accessible to the class itself
• Protected: methods are accessible to the class itself and inherited classes.

Exception

• PHP5 introduces exceptions handling.

Interfaces

• PHP5 introduces Interfaces.

E-Strict Error Level

• PHP5 introduces new error level defined as E_STRICT.
• E_STRICT will notify you when you use depreciated code.

Extensions

PHP5 introduces new default extensions.
• Simple XML
• DOM and XSL
• PDO
• Hash

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