PHP MCQ - Multiple Choice Questions

Welcome to Quiz on PHP. PHP is one of the most versatile server-side scripting languages, PHP powers a significant portion of the web. From websites to online applications, its ubiquity is undeniable. Whether you are a newbie aiming to grasp the foundational concepts or a seasoned developer looking to brush up on your PHP knowledge, our compilation of 40+ top multiple-choice questions (MCQs) will be a valuable resource.

In this guide, each MCQ comes with a correct answer and a detailed explanation, ensuring clarity and comprehensive understanding. We cover a broad spectrum of PHP topics, including:

PHP Syntax and Basics: Dive into the fundamental syntax rules and foundational concepts that make PHP tick.
Variables and Constants: Understand the essence of data storage and manipulation in PHP.
Control Structures: Learn how to dictate the flow of your PHP programs using conditional statements and loops.
Functions: Discover the modularity and reusability brought about by PHP functions.
Arrays: Grasp the intricacies of PHP’s most versatile data structure.
Strings and Regular Expressions: Delve into the world of textual data handling and pattern matching.
Object-Oriented Programming (OOP) in PHP: Explore the paradigm shift that OOP introduces, along with its array of concepts like classes, objects, properties, methods, inheritance, polymorphism, and much more.
File Handling: Learn how PHP interacts with files, allowing for data storage, retrieval, and manipulation.
Error and Exception Handling: Understand PHP’s robust mechanisms for dealing with unexpected scenarios and ensuring smooth execution.

1. What does PHP stand for?

a) Personal Hypertext Preprocessor

b) Public Home Page

c) Preprocessed Hypertext Page

d) PHP: Hypertext Preprocessor

Answer:

d) PHP: Hypertext Preprocessor

Explanation:

PHP originally stood for “Personal Home Page”, but it now stands for the recursive acronym “PHP: Hypertext Preprocessor.”

2. Who is often referred to as the father of PHP?

a) Mark Zuckerberg

b) Rasmus Lerdorf

c) Larry Page

d) Linus Torvalds

Answer:

b) Rasmus Lerdorf

Explanation:

Rasmus Lerdorf originally developed PHP in 1994. While others have since contributed and it has evolved, Rasmus is often recognized as the father of PHP due to his foundational work on the language.

3. Which of the options below represents the default file extension for PHP scripts?

a) .ph

b) .php5

c) .phtml

d) .php

Answer:

d) .php

Explanation:

While PHP files can occasionally be seen with extensions like .phtml or .php5 depending on the configuration or the context, the standard and most common default file extension for PHP scripts is .php.

4. What will the following code print?

a) HelloWorld!

b) Hello World!

c) Hello.World!

d) Error

Answer:

b) Hello World!

Explanation:

The . (dot) operator is used for string concatenation in PHP.

5. Which symbol is used to declare a variable in PHP?

a) !

b) &

c) %

d) $

Answer:

d) $

Explanation:

In PHP, variables are declared with the $ symbol.

6. How can you define a constant in PHP?

a) using the const keyword

b) using the define() function

c) using the $ symbol

d) both a and b

Answer:

d) both a and b

Explanation:

Constants in PHP can be defined using either the define() function or the const keyword.

7. Which of the following loops will execute the code block at least once and then evaluate the condition for subsequent repetitions?

a) do…while

b) for

c) foreach

d) while

Answer:

a) do…while

Explanation:

In the do…while loop, the code block gets executed once before the condition is checked. It then continues to execute as long as the condition is true.

8. Which loop is most appropriate for iterating over the elements of an array in PHP?

a) for

b) while

c) do…while

d) foreach

Answer:

d) foreach

Explanation:

The foreach loop is specifically designed for iterating over arrays in PHP. It provides an easy way to access both keys and values.

9. How can you break out of a loop prematurely in PHP?

a) Using the stop keyword

b) Using the break keyword

c) Using the exit keyword

d) Using the terminate keyword

Answer:

b) Using the break keyword

Explanation:

The break keyword is used to exit a loop prematurely in PHP.

10. Which statement is used to skip the current iteration of a loop and continue with the next one in PHP?

a) skip

b) jump

c) continue

d) next

Answer:

c) continue

Explanation:

The continue statement is used to skip the current iteration of a loop and proceed to the next one.

11. For a loop like for($i=0; $i<5; $i++),how many times will the loop execute?

a) 4 times

b) 5 times

c) 6 times

d) 0 times

Answer:

b) 5 times

Explanation:

The loop starts with $i at 0 and runs until $i is less than 5. So, it will run for 0, 1, 2, 3, and 4, which is a total of 5 times.

12. What is the primary purpose of the foreach loop in PHP?

a) Iterating only over numeric arrays

b) Iterating over properties of an object

c) Iterating over keys and/or values of an array

d) Iterating a fixed number of times

Answer:

c) Iterating over keys and/or values of an array

Explanation:

The primary purpose of the foreach loop in PHP is to iterate over the keys and/or values of an array.

13. If you want to loop indefinitely until a certain condition is met, which loop can you use?

a) for

b) while

c) do…while

d) Any of the above

Answer:

d) Any of the above

Explanation:

Any loop (for, while, or do…while) can be used to loop indefinitely until a specific condition is met, though it’s commonly achieved using while.

14. Which function can be used to check if a function exists in PHP?

a) func_exist()

b) is_function()

c) function_exists()

d) check_function()

Answer:

c) function_exists()

Explanation:

The function_exists() function checks if a given function has been defined.

15. How can you count the number of elements in an array $arr?

a) count($arr)

b) sizeof($arr)

c) $arr->length

d) both a and b

Answer:

d) both a and b

Explanation:

Both count() and sizeof() can be used to find the number of elements in an array.

16. Which of the following functions is used to replace a string?

a) str_replace()

b) str_swap()

c) replace_string()

d) swap_str()

Answer:

a) str_replace()

Explanation:

The str_replace() function is used for string replacement in PHP.

17. Which keyword is used to inherit a class in PHP?

a) inherit

b) extends

c) implements

d) uses

Answer:

b) extends

Explanation:

In PHP, the extends keyword is used to create a class that inherits the properties and methods from another class.

18. What is the main purpose of constructors in PHP OOP?

a) To destroy an object once it’s no longer needed.

b) To initiate an object’s properties when an object is created.

c) To clone an existing object.

d) To make the final changes before the object is destroyed.

Answer:

b) To initiate an object’s properties when an object is created.

Explanation:

Constructors are special methods that get automatically invoked when an object is instantiated. Their primary purpose is to initialize the object’s properties or to perform actions needed to set up the object.

19. Which keyword is used in PHP to create an instance of a class (an object)?

a) create

b) instantiate

c) new

d) instance

Answer:

c) new

Explanation:

The new keyword is used to create an instance of a class, i.e., an object.

20. Which of the following statements about interfaces in PHP is true?

a) Interfaces can have properties.

b) Interfaces can have both abstract and concrete methods.

c) Interfaces can be instantiated.

d) All methods declared in an interface are implicitly abstract.

Answer:

d) All methods declared in an interface are implicitly abstract.

Explanation:

In PHP, interfaces can only have abstract methods, which means they cannot have any concrete methods with a body.

21. In PHP OOP, what is the purpose of the final keyword when used with a class?

a) The class cannot be extended.

b) The class becomes an abstract class.

c) The class can no longer be instantiated.

d) The class becomes a parent class.

Answer:

a) The class cannot be extended.

Explanation:

When the final keyword is used before a class, it means that the class cannot be extended by any other class.

22. What is “polymorphism” in the context of PHP OOP?

a) The ability of a class to inherit properties and methods from multiple classes.

b) The process of using the same method in different ways for different data inputs.

c) The encapsulation of properties and methods within a single class.

d) The act of representing an abstract concept in the form of a class.

Answer:

b) The process of using the same method in different ways for different data inputs.

Explanation:

Polymorphism refers to the ability of OOP to present the same interface for differing data types. It allows the same method to be used in different ways for different inputs.

23. Which of the following PHP keywords is used to define an abstract class?

a) polymorphic

b) interface

c) virtual

d) abstract

Answer:

d) abstract

Explanation:

The abstract keyword is used to declare a class as abstract. Abstract classes cannot be instantiated directly, and they can contain abstract methods, which are methods without a body.

24. What does the “overloading” concept in OOP PHP refer to?

a) Redefining a method in a child class that is already present in the parent class.

b) Loading an object multiple times into memory.

c) Using the same method name but with a different number or type of parameters.

d) Increasing the memory allocated to an object during runtime.

Answer:

c) Using the same method name but with a different number or type of parameters.

Explanation:

In the context of OOP, overloading refers to the ability to use the same method or function name with different parameters.

25. If a class does not want to allow other classes to inherit from it, which keyword should it use?

a) sealed

b) final

c) abstract

d) noninherit

Answer:

b) final

Explanation:

In PHP, a class can be declared as final to prevent inheritance.

26. Which PHP function is used to read a file into an array?

a) file_into_array()

b) readfile()

c) file()

d) read_into_array()

Answer:

c) file()

Explanation:

The file() function in PHP reads a file into an array, with each line of the file as a separate element of the array.

27. Which function in PHP is used to check if a file exists?

a) is_file_exists()

b) file_exists()

c) exists_file()

d) check_file()

Answer:

b) file_exists()

Explanation:

The file_exists() function checks if the given file or directory exists.

28. Which of the following is NOT a valid PHP exception handling method?

a) throw

b) catch

c) try

d) error

Answer:

d) error

Explanation:

In PHP, exceptions are handled using the try, catch, and throw methods. error is not a method used for exception handling.

29. To handle user-defined exceptions, you should:

a) Use a predefined PHP exception class

b) Extend the base exception class

c) Use the error() function

d) None of the above

Answer:

b) Extend the base exception class

Explanation:

For user-defined exceptions, one should extend the base exception class and create custom exception classes as needed.

30. Which of the following PHP functions will output $x to the output buffer?

a) print()

b) echo

c) output()

d) Both a and b

Answer:

d) Both a and b

Explanation:

In PHP, both print() and echo can be used to output values to the output buffer.

31. Which PHP function returns the current timestamp?

a) time_now()

b) timestamp()

c) current_time()

d) time()

Answer:

d) time()

Explanation:

The time() function in PHP returns the current Unix timestamp.

32. Which function in PHP returns a part of a string?

a) str_part()

b) substr()

c) part_string()

d) string_cut()

Answer:

b) substr()

Explanation:

The substr() function in PHP returns a part of a string.

33. Which of the following delimiter is often used in regular expressions in PHP?

a) {}

b) []

c) ()

d) //

Answer:

d) //

Explanation:

In PHP, the // delimiters are often used to enclose regular expressions.

34. What does the end() function do in PHP for an array?

a) Resets the pointer to the beginning

b) Advances the pointer to the last element

c) Checks the end value of an array

d) None of the above

Answer:

b) Advances the pointer to the last element

Explanation:

The end() function in PHP moves the internal pointer of an array to its last element.

35. Which function can be used to sort an array in descending order in PHP?

a) sort_desc()

b) rsort()

c) sort_reverse()

d) d_sort()

Answer:

b) rsort()

Explanation:

The rsort() function sorts an array in descending order.

36. Which keyword is used to declare a class property as protected, meaning it can be accessed within the class itself and by its child or parent classes?

a) private

b) public

c) protected

d) internal

Answer:

c) protected

Explanation:

In PHP, the protected keyword is used to declare properties or methods that can be accessed within the class and by its child or parent classes.

37. What is the main difference between an interface and an abstract class in PHP?

a) An interface can have properties, while an abstract class cannot

b) An abstract class can have concrete methods, while an interface cannot

c) An interface can be instantiated, but an abstract class cannot

d) There’s no difference; they can be used interchangeably

Answer:

b) An abstract class can have concrete methods, while an interface cannot

Explanation:

In PHP, an abstract class can have both abstract and concrete methods, whereas an interface can only have abstract methods.

38. What function in PHP is used to open a file for reading only?

a) fopen_read()

b) file_open_read()

c) fread()

d) fopen(‘filename’, ‘r’)

Answer:

d) fopen(‘filename’, ‘r’)

Explanation:

The fopen() function with the ‘r’ parameter is used to open a file for reading only.

39. Which PHP function can be used to write to an open file?

a) fput()

b) fwrite()

c) write_file()

d) fappend()

Answer:

b) fwrite()

Explanation:

The fwrite() function in PHP can be used to write to an open file.

40. Which function sets a user-defined error handler function?

a) set_error_function()

b) user_error_handler()

c) set_error_handler()

d) define_error_handler()

Answer:

c) set_error_handler()

Explanation:

The set_error_handler() function allows you to define a custom error handler method.

41. In exception handling in PHP, which keyword is used to “catch” exceptions?

a) grab

b) except

c) catch

d) handle

Answer:

c) catch

Explanation:

In PHP’s exception handling, the catch block is used to catch exceptions thrown by the throw keyword.