C++ Functions MCQ Quiz - MCQ Questions and Answers

Welcome to "C++ Functions MCQ Quiz - MCQ Questions and Answers," a quiz designed to test and enhance your understanding of functions in C++. Functions are a cornerstone of C++ programming, essential for writing clean, modular, and efficient code. 

This quiz comprises 20 multiple-choice questions that range from basic to advanced levels, covering various aspects of function declaration, definition, scope, and usage in C++. Whether you're a student preparing for exams, a developer looking to refresh your knowledge, or an enthusiast eager to challenge your understanding of C++ functions, this quiz is a perfect tool. Get ready to dive into the intricacies of C++ functions and assess your programming prowess!

1. What is a function in C++?

a) A block of code that executes when the program starts

b) A named unit of code that can be invoked from other parts of the program

c) A variable declaration

d) A class member

Answer:

b) A named unit of code that can be invoked from other parts of the program

Explanation:

A function in C++ is a named block of code that performs a specific task and can be called from other parts of the program. It allows for code reuse and better organization.

2. How do you define a function in C++?

a) dataType functionName {parameterList}

b) functionName(dataType parameterList)

c) dataType functionName(parameterList) {body}

d) functionName: dataType(parameterList) {body}

Answer:

c) dataType functionName(parameterList) {body}

Explanation:

A function in C++ is defined with a return type (dataType), followed by the function name, a list of parameters (if any) inside parentheses, and the function body enclosed in braces.

3. What is function overloading in C++?

a) Changing the return type of a function

b) Creating a function inside another function

c) Having multiple functions with the same name but different parameters

d) Calling a function multiple times

Answer:

c) Having multiple functions with the same name but different parameters

Explanation:

Function overloading in C++ allows multiple functions to have the same name with different parameters, enabling the same function name to perform different tasks based on arguments.

4. What is the main difference between a function and a method in C++?

a) A function cannot return a value, while a method can

b) A function is defined inside a class, while a method is not

c) A method is a function defined inside a class

d) There is no difference

Answer:

c) A method is a function defined inside a class

Explanation:

In C++, a method is essentially a function that is defined within a class. It operates on the data contained within the class.

5. What is a default argument in a function in C++?

a) An argument that is always required

b) An argument that the function uses if no corresponding argument is passed

c) The first argument in a function

d) An argument that defaults to zero

Answer:

b) An argument that the function uses if no corresponding argument is passed

Explanation:

Default arguments in C++ functions are used when no actual argument is provided in the function call. They allow functions to be called with fewer arguments than they are defined with.

6. What is a 'const' member function in C++?

a) A function that can modify the object it is called on

b) A function that cannot change any class member variables

c) A function that is always called first

d) A constructor function

Answer:

b) A function that cannot change any class member variables

Explanation:

A 'const' member function in C++ is one that cannot modify the object on which it's called. It guarantees not to change any class member variables.

7. What is the return type of a constructor in C++?

a) void

b) The type of the class

c) It has no return type

d) int

Answer:

c) It has no return type

Explanation:

Constructors in C++ do not have a return type, not even void. They are special member functions used to initialize objects of its class.

8. Which of the following is true about inline functions in C++?

a) They are always faster than regular functions

b) The compiler may ignore the inline request

c) They cannot have a loop

d) They are defined outside the class

Answer:

b) The compiler may ignore the inline request

Explanation:

Inline functions are a request to the compiler to replace the function call with the function's code. However, the compiler may ignore this request based on its optimization settings or the complexity of the function.

9. What is recursion in C++?

a) A loop in a function

b) A class calling another class

c) A function calling itself

d) Overloading a function

Answer:

c) A function calling itself

Explanation:

Recursion in C++ is the process of a function calling itself directly or indirectly, which allows the function to repeat its behavior until a base condition is met.

10. What is a static function in C++?

a) A function that can be called without creating an object

b) A function that retains its values between calls

c) A function that cannot be changed

d) A member function that is called automatically

Answer:

a) A function that can be called without creating an object

Explanation:

Static functions in C++ are functions that belong to the class rather than any object instance. They can be called without creating an instance of the class.

11. How are function arguments passed in C++ by default?

a) By reference

b) By value

c) By pointer

d) By constant reference

Answer:

b) By value

Explanation:

By default, arguments in C++ functions are passed by value, meaning a copy of the argument is made and used inside the function.

12. What is the purpose of a function prototype in C++?

a) To define a function

b) To declare a function before its usage

c) To initialize function variables

d) To terminate a function

Answer:

b) To declare a function before its usage

Explanation:

A function prototype in C++ is a declaration of a function that specifies the function's name, return type, and parameters, without the function body. It informs the compiler about the function before its actual definition.

13. What are variadic functions in C++?

a) Functions that can take a variable number of arguments

b) Functions that return variable values

c) Functions that vary in return type

d) Functions that can be called in various ways

Answer:

a) Functions that can take a variable number of arguments

Explanation:

Variadic functions in C++ are functions that can accept a variable number of arguments. They are useful for functions where the number of arguments is not fixed, like printf().

14. What is the significance of the 'main' function in C++?

a) It indicates the end of the program

b) It is the first function that gets called when a program starts

c) It is used to define methods

d) It is a special class constructor

Answer:

b) It is the first function that gets called when a program starts

Explanation:

The 'main' function in C++ is the entry point of a C++ program. When the program is executed, the 'main' function is the first function to be called.

15. How do you define a function that returns a reference in C++?

a) dataType& functionName(parameters)

b) &dataType functionName(parameters)

c) dataType functionName&(parameters)

d) dataType functionName(parameters)&

Answer:

a) dataType& functionName(parameters)

Explanation:

To define a function that returns a reference in C++, the return type should be followed by an ampersand (&), indicating that the function returns a reference.

16. What is a lambda function in C++?

a) A function used only in loops

b) An anonymous function

c) A predefined function in the standard library

d) A recursive function

Answer:

b) An anonymous function

Explanation:

A lambda function in C++ is an anonymous function or a function without a name. It is useful for short snippets of code that are not going to be reused and do not require naming.

17. What happens when a function is declared as 'friend' in a class?

a) It can access all private and protected members of the class

b) It becomes a member function of the class

c) It can only be called by other member functions

d) It is automatically inlined

Answer:

a) It can access all private and protected members of the class

Explanation:

When a function is declared as a 'friend' in a class, it is not a member function of the class but can access all private and protected members of the class.

18. What is the correct syntax for a function pointer in C++?

a) dataType (*functionName)(parameters)

b) dataType *functionName(parameters)

c) dataType functionName*(parameters)

d) *dataType functionName(parameters)

Answer:

a) dataType (*functionName)(parameters)

Explanation:

A function pointer in C++ is declared with the return type, followed by an asterisk within parentheses along with the function pointer name, and the parameters.

19. What is meant by default parameters in C++ functions?

a) Parameters that are optional and have default values

b) Parameters that are always required

c) The first parameter in a function

d) Parameters that default to NULL

Answer:

a) Parameters that are optional and have default values

Explanation:

Default parameters in C++ functions are parameters that have default values assigned to them. They are optional in function calls. If not provided, the default values are used.

20. What is the use of the 'return' statement in C++?

a) To exit the program

b) To return control to the calling function

c) To print a value

d) To terminate a loop

Answer:

b) To return control to the calling function

Explanation:

The 'return' statement in a C++ function is used to return control to the function that called it. If the function has a return type other than void, the 'return' statement also returns a value.