Question:Which programming language does PHP resemble to? 

PHP syntax resembles Perl and C

Question:What is the main difference between PHP 4 and PHP 5? 

PHP 5 presents many additional OOP (Object Oriented Programming) features.

Question:Discuss five predefined subscript of $_FILES super global variable? 

a. $_FILES['file']['name']: The name of the file as uploaded from the client to the server.
b. $_FILES['file']['type']: The MIME type of the uploaded file. Whether this variable is assigned depends on the browser capabilities.
c. $_FILES['file']['size']: The byte size of the uploaded file.
d. $_FILES['file']['tmp_name']: Once uploaded, the file will be assigned a temporary name before it is moved to its final location.
e. $_FILES['file']['error']: An upload status code.

Question:Why explode() is used?

 

The explode() function splits a string into a series of substrings, with each string boundary determined by a specific separator.
 
Its prototype: explode(string separator, string string [, int limit]).

Question:What are passing arguments by reference and passing arguments by value?

 

Passing arguments by value: 
Means any changes made to those values within the scope of the function are ignored outside of the function.
Passing arguments by reference: 
Means any changes made to those values within the scope of the function are reflected outside of the function.

Question:What does accessing a class via :: operator means? 

:: operator is used to access static methods that do not require object initialization.

Question:How to initiate a session in PHP? 

The use of the function session_start() lets us activating a session.

Question:How can we determine whether a variable is set? 

The boolean function isset determines if a variable is set and is not NULL.

Question:What is object cloning?

 

If we try to copy a referenced object, it will simply point back to the addressing location of the original object. To remedy the problems with copying, PHP offers an explicit means for cloning an object which is known as object cloning.

Question:What are the four configuration directive scopes? 

Configuration directive scopes are given bellow:
PHP_INI_PERDIR: Directive can be modified within the php.ini,httpd.conf, or .htaccess files.
PHP_INI_SYSTEM: Directive can be modified within the php.ini and httpd.conf files.
PHP_INI_USER: Directive can be modified within user scripts.
PHP_INI_ALL: Directive can be modified anywhere.