Top C++ MCQs for Freshers and Experienced Candidates

These basic C++ MCQ questions and answers cover syntax, data types, operators, and foundational concepts.

You’ll learn fundamental C++ concepts such as identifiers, operators, syntax rules, I/O operations, data types, keywords, scope resolution, and more. These are essential for clearing first-round interviews and coding exams.

1. Which of the following is the correct way to declare a variable in C++?

A) int x;
B) var x;
C) integer x;
D) declare x;

Answer: A)

Explanation: C++ uses standard data type declarations like int, float, char. Other options are not valid syntax.

2. Which header file is needed for cout and cin?

A) <stdio.h>
B) <conio.h>
C) <iostream>
D) <stream>

Answer: C)

Explanation: Input/output objects like cout and cin are defined in <iostream>.

3. What is the correct way to write a comment in C++?

A) % comment
B) /* comment */
C) -- comment
D) # comment
Answer: B)

Explanation: C++ allows both single-line (//) and multi-line (/*...*/) comments.

4. Which of these is not a C++ data type?

A) int
B) float
C) real
D) char
Answer: C)

Explanation: real is not a built-in C++ type.

5. What is the size of a char in C++?

A) 1 byte
B) 2 bytes
C) 4 bytes
D) 8 bytes
Answer: A)

Explanation: char always takes 1 byte, regardless of system.

6. Which operator is used for input in C++?

A) >>
B) <<
C) <~
D) ->
Answer: A)

‍Explanation: >> is the extraction operator used with cin.

7. Which of the following is a valid identifier?

A) 2value
B) value2
C) value-2
D) value 2
Answer: B)

‍Explanation: Identifiers cannot start with digits or contain hyphens/spaces.

8. What is the default value of an uninitialized int local variable?

A) 0
B) Garbage value
C) -1
D) Compiler dependent
Answer: B)

‍Explanation: Local variables contain garbage unless explicitly assigned.

9. Which operator is used for scope resolution?

A) .
B) ::
C) ->
D) :
Answer: B)

‍Explanation: :: accesses global variables or namespace members.

10. Which keyword creates a constant variable?

A) fixed
B) static
C) const
D) var
Answer: C)

‍Explanation: const ensures variable value cannot change.

11. Which feature does C++ support?

A) OOP
B) Procedural programming
C) Generic programming
D) All of the above
Answer: D)

‍Explanation: C++ is a multi-paradigm language.

12. Which symbol ends a C++ statement?

A) :
B) ;
C) .
D) ,
Answer: B)

13. Which keyword is used to include libraries?

A) import
B) include
C) using
D) library
Answer: B)

14. Which of the following is a user-defined data type?

A) int
B) float
C) struct
D) char
Answer: C)

15. Which of these creates a single-line comment?

A) #
B) --
C) //
D) /*
Answer: C)

16. Which function is used to start C++ program execution?

A) start()
B) execute()
C) main()
D) run()
Answer: C)

17. Which operator has the highest precedence?

A) +
B) *
C) =
D) ()
Answer: D)

18. Which is used to create a new line?

A) /n
B) \n
C) endl;
D) Both B and C
Answer: D)

19. What is the size of bool?

A) 1 byte
B) 2 bytes
C) 4 bytes
D) Not fixed
Answer: A)

20. Which operator is used for dynamic memory allocation?

A) malloc
B) alloc
C) new
D) create
Answer: C)

21. Which of these is a logical operator?

A) &&
B) ||
C) !
D) All
Answer: D)

22. Which is the insertion operator?

A) <<
B) >>
C) <#
D) <|
Answer: A)

23. Which header defines string class?

A) <string>
B) <str>
C) <cstring>
D) <stdio.h>
Answer: A)

24. What is the extension of a C++ source file?

A) .cp
B) .c++
C) .cpp
D) .cxx
Answer: C)

25. Which feature of C++ enables function overloading?

A) Polymorphism
B) Encapsulation
C) Inheritance
D) Abstraction
Answer: A)

26. What is a container in C++ STL?

A) A function template
B) A macro
C) A class that stores objects/data
D) An operator
Answer: C)

Explanation: Containers are classes in the Standard Template Library (STL) that store collections of objects.

These C++ MCQ questions focus on pointers, references, OOP basics, dynamic allocation, constructors, destructors, and exception handling, core topics for C++ MCQs for placement.

1. Which of the following about pointers is correct?

A) Store values directly
B) Can be null
C) Cannot change address
D) Not variables
Answer: B)

Explanation: Pointers store addresses and can legally hold a null pointer to indicate no object reference.

2. What will this print?

int x = 5, y = 10;
cout << x + y;

A) 15
B) 510
C) Error
D) None
Answer: A)

3. Which keyword throws an exception?

A) error
B) throw
C) raise
D) except
Answer: B)

4. Which feature protects data from unauthorized access?

A) Inheritance
B) Polymorphism
C) Abstraction
D) Encapsulation
Answer: D)

5. Which function is called when an object goes out of scope?

A) constructor
B) destructor
C) final
D) end()
Answer: B)

6. What is the purpose of static variables?

A) Block-scope + persistent value
B) Global
C) Temporary
D) None
Answer: A)

7. Which of these cannot be overloaded?

A) +
B) []
C) ::
D) ()

Answer: C)

8. What does malloc return in C++?

A) void*
B) int*
C) char*
D) depends

Answer: A)

9. Which constructor runs without arguments?

A) Parameterized
B) Copy
C) Default
D) Inline

Answer: C)

10. Which specifier is used for inheritance?

A) :
B) ->
C) ::
D) <

Answer: A)

11. A class is a ______ ?

A) Object
B) Blueprint
C) Variable
D) Instance

Answer: B)

12. Which keyword creates an object dynamically?

A) new
B) malloc
C) create
D) build
Answer: A)

13. How are objects passed to functions?

A) By value
B) By reference
C) Both
D) None
Answer: C)

14. This pointer points to?

A) class
B) current object
C) base class
D) child
Answer: B)

15. Which function copies objects?

A) copy()
B) assign()
C) copy constructor
D) clone()
Answer: C)

16. What is function overloading?

A) Using one function for all operations
B) Defining many functions with distinct arguments but the same name
C) Using macros
B) Defining functions inside classes only
Answer: B)

Explanation: Function overloading allows functions with the same name but different parameter lists.

17. Which keyword is used to throw an exception?

A) catch
B) throw
C) try
D) handle
Answer: B)

Explanation: The throw keyword generates an exception

These​‍​‌‍​‍‌​‍​‌‍​‍‌ advanced C++ multiple-choice questions include topics such as memory management, virtual functions, RAII, templates, references, move semantics, operator overloading, inheritance models, and polymorphism. They represent an excellent resource to help you get ready for interviews and competitive ​‍​‌‍​‍‌​‍​‌‍​‍‌placements.

1. Which of the following concepts enables runtime polymorphism?

A) Function overloading
B) Operator overloading
C) Virtual functions
D) Templates
Answer: C)

‍Explanation: Virtual functions allow dynamic binding, enabling function calls to be resolved at runtime rather than compile time.

2. What does RAII mean in C++?

A) Resource Allocation is Independent
B) Resource Acquisition Is Initialization
C) Random Access Is Initialization
D) None
Answer: B)

‍Explanation: RAII ensures resources (memory, file handles) are acquired in constructors and released in destructors.

3. Which operator cannot be overloaded?

A) +
B) =
C) []
D) ::
Answer: D)
Explanation: The Scope resolution operator is fundamental to namespaces and cannot be overloaded.

4. What does the delete operator do?

A) Allocates memory
B) Frees dynamically allocated memory
C) Copies an object
D) Deletes a file
Answer: B)

5. Which class cannot be instantiated?

A) Normal class
B) Abstract class
C) Final class
D) Derived class
Answer: B)‍

Explanation: A class with at least one pure virtual method cannot be instantiated.

6. Which keyword prevents inheritance?

A) const
B) static
C) final
D) private
Answer: C)

Explanation:

The​‍​‌‍​‍‌​‍​‌‍​‍‌ final modifier in Java is a way of expressing that the class cannot be further inherited. When it is applied to a class or a method, it stops any subclass from changing or extending the class or the method. In this way, it is used to ensure that the developer retains the control over the design of the program.

7. What is a shallow copy?

A) Copies pointer values only
B) Copies whole object deeply
C) Deletes object
D) None
Answer: A

Explanation:

A shallow copy only duplicates the pointer addresses, i.e. the references, not the actual data they point to. That is why multiple objects will point to the same memory location and operations performed on that memory will affect all of the objects, which can lead to problems such as crashing the program when trying to delete the memory twice.

8. What is mandatory for operator overloading?

A) At least one operand must be a class object
B) Only built-in types allowed
C) Requires pointers
D) None
Answer: A

Explanation:

Operator overloading has to involve at least one user-defined type (class or struct). This rule is made to stop programmers from changing the predefined behavior of built-in operators for primitive types.

9. Which constructor is called during object passing by value?

A) Copy constructor
B) Default constructor
C) Move constructor
D) Destructor
Answer: A

Explanation:

When an object is passed by value, a temporary object is created to hold the passed object, and this temporary object is the one that is passed to the function. This copying process triggers the copy constructor.

10. Which cast is safest?

A) reinterpret_cast
B) static_cast
C) dynamic_cast
D) const_cast
Answer: C

Explanation:

dynamic_cast is the one that does validation during runtime of the requested downcast and therefore it is the safest one. In case of an incorrect cast, it yields nullptr in the case of pointers and throws an exception in the case of references, thus it is not possible to have an unsafe ​‍​‌‍​‍‌​‍​‌‍​‍‌conversion.

11. What is the primary use of inline functions?

A) Faster execution
B) Memory safety
C) Exception handling
D) None
Answer: A

Explanation:

Inline functions eliminate calling costs by substituting the actual function code for a function call. As a result, the program can execute more quickly, particularly when the function is tiny and often utilized.

12. How many destructors can a class have?

A) 0
B) 1
C) Multiple
D) Depends
Answer: B

Explanation:

Only one destructor can be present in a C++ class. It performs the cleanup operations before the destruction of the object, and if there were more than one destructors, it would be unclear which one to call.

13. What is the default visibility mode in inheritance?

A) public
B) private
C) protected
D) static
Answer: B

Explanation:

If a class is inherited without access type being specified, it is assumed that the inheritance is private in C++. In that case, the members of the base class become private in the derived class.

14. Which method is invoked before main()?

A) _start()
B) Constructor
C) Static initialization blocks
D) None
Answer: C

Explanation:

Static initialization (for example, of global objects, static objects) is done before main() is started. In C++, initialization of static storage objects is part of program startup.

15. What happens when memory is freed twice?

A) Success
B) Crash
C) Leak
D) Warning
Answer: B‍

Explanation:
Freeing the same block of memory twice is going to produce undefined behavior which in most cases leads to program crashes. It is one of the most common bugs in manual memory management.

16. Templates enable what feature?

A) Runtime polymorphism
B) Compile-time polymorphism
C) Memory management
D) I/O handling
Answer: B‍

Explanation:
Templates enable compile-time polymorphism as they allow functions and classes to work with generic types. The main advantage is that their use is flexible without any loss of performance.

17. What kind of problem can smart pointers prevent?

A) Syntax errors
B) Dangling pointers
C) Compilation issues
D) Deadlocks
Answer: B‍

Explanation:
Smart pointers are automatic memory managers that also delete the resource when it is no longer used. Hence, the problem of dangling pointers and memory leaks is solved.

18. Which keyword disables function overriding?

A) stop
B) end
C) final
D) const
Answer: C‍

Explanation:
A virtual function is marked as final to prevent derived classes from overriding it.  It acts as a means of guaranteeing that the behavior remains consistent across the class hierarchy.

19. Which C++ feature can be used to link resource lifetime with object lifetime?

A) Pointers
B) RAII
C) Macros
D) Arrays
Answer: B‍

Explanation:
RAII (Resource Acquisition Is Initialization) ensures that resources are acquired in constructors and released in destructors. This prevents leaks and guarantees cleanup.

20. Which requires a virtual destructor?

A) Static class
B) Base class with polymorphism
C) Local class
D) None
Answer: B‍

Explanation:
If a base class is to be used polymorphically, then it should be provided with a virtual destructor. The reason is, if a derived object is deleted through a base pointer, properly destroying the derived object won't happen.

21. Move semantics improve what?

A) Memory leaks
B) Copy performance
C) Runtime errors
D) Inheritance
Answer: B‍

Explanation:
Move semantics transfer ownership of resources instead of copying them. This avoids expensive deep copies and significantly increases performance for large objects.

22. What is std::unique_ptr used for?

A) Shared ownership
B) Exclusive ownership
C) No ownership
D) Raw pointer replacement
Answer: B‍

Explanation:
unique_ptr is the pointer that guarantees that only one pointer is responsible for a resource at a time. When a unique_ptr is going out of scope, it will automatically release the memory thereby preventing leaks.

23. Which keyword is linked with namespaces?

A) using
B) import
C) namespaceof
D) name
Answer: A

Explanation:

Using is the keyword which allows to bring either whole the namespace or just one element from it to the current scope. Besides that, it is a great help in avoiding long names of namespaces.

24. Which type of inheritance can cause ambiguity?

A) Single
B) Multi-level
C) Multiple
D) Hierarchical
Answer: C

Explanation:
If members of two base classes share the same name, multiple inheritance might lead to confusion. C++ use virtual inheritance or scope resolution to address this problem.

25. Pure virtual functions make a class?

A) Polymorphic
B) Static
C) Abstract
D) Encapsulated

Answer: C

Explanation:
A class with at least one pure virtual function is considered abstract; hence, it cannot be instantiated. Such a class serves as a template for the derived classes.

26. What is a vtable (virtual table) in C++?

A) A table of variable names
B) A table of function pointers used for dynamic dispatch
C) A table of container sizes
D) A table of class names

Answer: B)

Explanation: 

The vtable is the mechanism used to support dynamic (runtime) polymorphism in classes with virtual functions.

These C++ program multiple choice questions test real output prediction skills across references, pointers, loops, functions, OOP, memory behavior, and exception ​‍​‌‍​‍‌​‍​‌‍​‍‌handling.

1. 

int x = 10;
int &y = x;
y++;
cout << x;

A) 10
B) 11
C) Error
D) Undefined

Answer: B

Explanation: 

y is a reference to x, i.e. both names refer to the same memory location. Incrementing y hence indirectly increments x. Thus, x becomes 11, and it is printed.

2. 

int a = 5;
cout << a++ << " " << a;

A) 5 5
B) 5 6
C) 6 6
D) 6 5

Answer: B

Explanation: 

Post-increment returns the old value and then increments. So the first printed value is 5, then a is incremented to 6, thus the second printed value is 6.

3. 

int arr[] = {1, 2, 3};
cout << arr[1];

A) 1
B) 2
C) 3
D) Error

Answer: B

Explanation: 

Elements of an array in C++ are addressed starting from zero. arr[1] refers to the second element of the array which is 2. Nothing in this snippet is invalid.

4. 

cout << sizeof(double);

A) 4
B) 8
C) 2
D) System dependent

Answer: B

Explanation: On all modern systems, double occupies 8 bytes, as per IEEE 754 standard. While technically system-dependent, 8 bytes is the consistent practical value.

5. 

string s = "Hello";
cout << s.length();

A) 4
B) 5
C) 6
D) Error
Answer: B‍

Explanation: The string "Hello" contains five characters. length() returns the number of characters in the string, not including any terminator.

6. 

int a = 10;
int *p = &a;
cout << *p;

A) 10
B) Address
C) Garbage
D) Error
Answer: A‍

Explanation: p stores the address of a, and *p retrieves the value at that address. Since a is 10, dereferencing the pointer prints 10.

7. 

int a = 3;
int b = ++a * 2;
cout << b;

A) 6
B) 8
C) 4
D) Error
Answer: B‍

Explanation: Pre-increment changes a before it is used, thus a becomes 4. Then b = 4 × 2, resulting in 8 as the final ​‍​‌‍​‍‌​‍​‌‍​‍‌value.

8. 

int x = 5;
cout << (x > 3 ? 10 : 20);

A) 10
B) 20
C) 5
D) Error
Answer: A‍

Explanation: The ternary operator chooses the first number (10) since the condition x > 3 evaluates to true. Here, no expressions result in mistakes.

9. 

int x = 5;
int y = 10;
cout << (x == 5 && y == 10);

A) 0
B) 1
C) 10
D) Error
Answer: B‍

Explanation: The logical AND yields true as both comparisons evaluate to true. In an integer context, true in C++ is written as 1.

10. 

class A {
public:    
A() 
{ 
cout << "A"; 
}
};
A obj;

A) A
B) nothing
C) error
D) constructor
Answer: A‍

Explanation: Creating an object of class A automatically calls its constructor. The constructor prints "A" during object creation before main finishes.

11. 

int x = 3;
int y = x << 1;
cout << y;

A) 3
B) 6
C) 8
D) Error
Answer: B‍

Explanation: Left shift by 1 multiplies the number by 2 for positive integers. So 3 << 1 becomes 6.

12. 

int a = 10;
int b = 20;
swap(a, b);
cout << a;

A) 10
B) 20
C) Error
D) Undefined
Answer: B‍

Explanation: The STL swap() function exchanges the values of a and b. After the swap, a holds 20.

13. 

for(int i = 0; i < 3; i++)    
cout << i;

A) 012
B) 123
C) 01
D) 23
Answer: A‍

Explanation: The loop prints values starting from 0 and continues until i < 3 fails. Thus, the loop prints 0, 1, and 2.

14. 

int a = 5;
int *p = &a;
*p = *p + 5;
cout << a;

A) 5
B) 10
C) 0
D) Error
Answer: B‍

Explanation: Dereferencing p modifies the value of a directly. Adding 5 makes a = 10, which is printed.

15. 

try {
    throw 10;
}
catch(int x) {
    cout << "Error";
}

A) Error
B) 10
C) Crash
D) None

Answer: A

Explanation: The thrown integer is caught by the matching catch(int) handler. Inside the catch block, "Error" is printed.

16. 

int x = 1;
while(x < 4){
    cout << x;
    x++;
}

A) 123
B) 12
C) 14
D) None

Answer: A

Explanation: The loop prints 1, then 2, then 3, stopping when x becomes 4. All iterations are valid and sequential.

17. 

string s = "abc";
s += "d";
cout << s;

A) abc
B) abcd
C) abd
D) Error

Answer: B

Explanation: Using += appends characters to the existing string. "abc" becomes "abcd" and is printed.

18. 

int x = 10 / 3;
cout << x;

A) 3
B) 3.3
C) 4
D) Error

Answer: A

Explanation: Integer division discards the decimal part. 10 / 3 produces 3 because both operands are integers.

19. 

int a = 5;
int b = 2;
cout << a % b;

A) 1
B) 2
C) 0
D) 5

Answer: A

Explanation: The modulo operator returns the remainder. 5 % 2 leaves a remainder of 1.

20. 

int arr[3] = {3, 6, 9};
cout << arr[0] + arr[2];

A) 12
B) 9
C) 6
D) 15

Answer: A

Explanation: The first and last array elements are 3 and 9. Their sum is 12.

21. 

class Base { 
public: 
    virtual void show(){ cout<<"B"; } 
};
class D : public Base { 
public: 
    void show(){ cout<<"D"; } 
};
Base *b = new D;
b->show();

A) B
B) D
C) Error
D) None
Answer: B

Explanation: The show() function is virtual, enabling runtime polymorphism. Since the pointer refers to a derived object, the derived method prints "D".

22. 

int a = 1;
if(a = 0)
    cout << "Zero";
else
    cout << "Non-zero";

A) Zero
B) Non-zero
C) Error
D) None

Answer: B

Explanation: a = 0 is assignment, not comparison. It assigns 0 to a and evaluates to false, so the else block prints "Non-zero".

23.

cout << (5 < 10 ? 100 : 200);

A) 100
B) 200
C) 10
D) Error

Answer: A

Explanation: Because 5 < 10 is true, the ternary operator selects the first value, 100. The expression is valid as-is.

24. 

int x = 5;
cout << &x;

A) 5
B) Address
C) Error
D) Undefined

Answer: B

Explanation: &x prints the memory address where x is stored. The actual address varies at runtime but is well-defined and valid.

25. 

class A{
public:
    ~A(){ cout << "Bye"; }
};
int main(){
    A obj;
}

A) Nothing
B) Bye
C) Error
D) None
Answer: B

Explanation: When obj goes out of scope at the end of main, its destructor is automatically invoked. The destructor prints "Bye" before program exit.

C++ remains one of the most essential programming languages for students, job seekers, and software professionals. This collection of 100 carefully designed multiple-choice questions covers fundamental concepts, intermediate logic, advanced features, and practical code analysis.

Points to Remember

• C++​‍​‌‍​‍‌​‍​‌‍​‍‌ is capable of implementing all three types of programming paradigms, i.e. procedural, object-oriented, and generic. 
• Regularly practice MCQs to become proficient in syntax, memory management, OOP, and pointers. 
• Understanding references, virtual functions, constructors, and destructors is crucial for obtaining placements.
• Using MCQs with code snippets develops practical debugging and logical reasoning skills.
• A combination of basic, intermediate or advanced types of C++ objective questions and answers is the best method of studying for success in obtaining placement opportunities.

1. What are C++ MCQs and why are they important?

Multiple​‍​‌‍​‍‌​‍​‌‍​‍‌ Choice Questions (MCQs) in C++ is a set of objective questions that offer the person being tested a selection of answers. Questions with multiple choices in C++ are used to check the knowledge of the person being tested regarding various topics of C++. C++ multiple-choice questions (MCQs) permit students to measure their learning, recognize their strong and weak points, and thus prepare for a test or an interview by simulating the testing ​‍​‌‍​‍‌​‍​‌‍​‍‌environment.

2. What topics are commonly covered in C++ MCQs?

C++ MCQs usually cover a broad range of topics, including syntax, data types, operators, pointers, object-oriented programming (OOP), memory management, Standard Template Library (STL), templates, exception handling, and code output prediction.

3. Are these MCQs updated for modern C++ standards (C++11/14/17/20)?

Most questions focus on core C++ concepts, but it’s always helpful to supplement your learning with the latest features and best practices from newer C++ standards.

4. Are C++ MCQs enough to prepare for coding interviews?

C++ MCQs are excellent for building strong conceptual foundations, but interviews also require hands-on coding practice. Use MCQs to master concepts like pointers, OOP, memory management, and STL, then complement them with coding problems and projects.

5. How do C++ MCQs help in improving programming skills?

MCQs help reinforce theory, reveal misconceptions, and strengthen your understanding of how C++ works internally, especially with tricky concepts like references, dynamic memory, operator precedence, and object lifetimes.

6. How does C++ handle string manipulation and what is the role of std::string?

C++ provides the std::string class for easy and efficient string manipulation. Unlike character arrays, std::string supports dynamic resizing, concatenation, and a wide range of built-in functions such as .length(), .substr(), .find(), and .replace(). This makes working with text data safer and more convenient compared to traditional C-style strings.

7. What are streams in C++, and how are they used for input and output operations?

Streams in C++ represent the entities through which input and output operations are performed. Standard ones are iostream for console I/O (cin, cout), fstream for file I/O, and stringstream for in-memory string operations. Stream operations involve usage of operators like << and >> to get data from or send data to different sources. This way, streams allow a uniform, type-safe way of handling data irrespective of the context.

8. Are the C++ MCQs in this blog suitable for beginners?

Yes,​‍​‌‍​‍‌​‍​‌‍​‍‌ this blog has fundamental, intermediate, and advanced level multiple-choice questions with some code snippets as well. So it is an excellent resource for fresh graduates, college students, and experienced learners who are looking for the interview patterns or competitive ​‍​‌‍​‍‌​‍​‌‍​‍‌​‍​‌‍​‍‌​‍​‌‍​‍‌exams.

9. Where can I use these MCQs for practice?

These C++ MCQs can be used for university exam preparation, placement exams, online coding assessments, mock tests, self-evaluation, and interview preparation. They are designed to help you test your speed, logic, and conceptual understanding effectively.