C++ Pointers Interview Questions 2026: 28 Q&A With Code

Last Updated: June 2026 | Level: Freshers to Mid-Level | Read Time: ~16 min

Pointers are the part of C++ that interviewers use to separate people who understand memory from people who memorise syntax. Candidates report that pointer versus reference, dynamic allocation, and dangling-pointer bugs are guaranteed for systems and product roles. This guide covers 28 pointer questions with full answers and predict-the-output traps. Behaviour reflects the official cppreference documentation; confirm any memory semantics on the standard.

Pair this with C++ Programming Placement Questions and C++ OOPs Interview Questions 2026.

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Table of Contents

1. Basics (Q1 to Q9)
2. References and const (Q10 to Q16)
3. Dynamic Memory (Q17 to Q23)
4. Smart Pointers and Advanced (Q24 to Q28)
5. Predict the Output
6. Quick Revision Table
7. Frequently Asked Questions

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Basics

Q1. What is a pointer? Easy

int x = 5;
int* p = &x;
cout << *p;   // 5

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Q2. What is the difference between a pointer and a reference? Medium

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Q3. What is a null pointer? Easy

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Q4. What is a dangling pointer? Medium

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Q5. What is a wild pointer? Easy

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Q6. What is pointer arithmetic? Medium

int a[3] = {10,20,30};
int* p = a;
cout << *(p + 1);   // 20

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Q7. What is a void pointer? Medium

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Q8. What is a function pointer? Medium

int add(int a,int b){return a+b;}
int (*fp)(int,int) = add;
fp(2,3);   // 5

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Q9. What is the difference between *p++ and (*p)++? Hard

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References and const

Q10. What is a const pointer vs a pointer to const? Hard

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Q11. Can a reference be null? Medium

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Q12. What is pass by reference vs pass by pointer? Medium

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Q13. What is a reference to const used for? Medium

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Q14. What is an rvalue reference? Hard

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Q15. What does std::move actually do? Hard

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Q16. What is the difference between a reference and a pointer parameter for swapping? Medium

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Dynamic Memory

Q17. What is the difference between new and malloc? Medium

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Q18. What is the difference between delete and delete[]? Medium

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Q19. What is a memory leak? Easy

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Q20. What is a double free? Hard

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Q21. How do you allocate a 2D array dynamically? Hard

vector<vector<int>> grid(rows, vector<int>(cols, 0));

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Q22. What is the heap vs the stack? Medium

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Q23. What happens if new fails? Medium

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Smart Pointers and Advanced

Q24. What are smart pointers and why use them? Medium

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Q25. What is the difference between unique_ptr and shared_ptr? Hard

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Q26. What problem does weak_ptr solve? Hard

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Q27. What is a dangling reference and how is it different from a dangling pointer? Hard

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Q28. What is the difference between shallow and deep copy of a pointer member? Medium

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Predict the Output

Snippet 1

int a[] = {10, 20, 30};
int* p = a;
cout << *(p + 2) << " " << *p + 2;

Output:

30 12

Why: *(p+2) reads the third element 30. *p + 2 reads the first element 10 and adds 2 to get 12. Precedence trap.

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Snippet 2

int x = 5;
int* p = &x;
int** pp = &p;
**pp = 99;
cout << x;

Output:

99

Why: pp points to p which points to x; double dereference writes through to x.

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Snippet 3

int* p = new int(7);
delete p;
cout << *p;

Output:

(undefined behaviour)

Why: p is dangling after delete; dereferencing freed memory is undefined. Set p = nullptr after delete.

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Quick Revision Table

Concept	Key takeaway
pointer vs reference	reseatable nullable vs fixed alias
dangling pointer	used after free, undefined
const placement	read right to left
new vs malloc	constructs vs raw bytes
delete vs delete[]	single vs array
smart pointers	auto free, no manual delete
weak_ptr	breaks shared_ptr cycles

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Frequently Asked Questions

What pointer topic is asked most in C++ interviews in 2026?

Candidates report that the difference between a pointer and a reference, dynamic allocation with new and delete, and dangling pointers and memory leaks are the most repeated C++ pointer questions.

Are smart pointers replacing raw pointers in interviews?

Modern interviews expect you to prefer unique_ptr and shared_ptr for ownership while still understanding raw pointers for non-owning access and pointer arithmetic.

What is the most common pointer bug in interviews?

The dangling pointer: using a pointer after the memory it points to has been freed or gone out of scope. Closely followed by double free and forgetting to delete, which leaks.

How do I read a complex pointer declaration like const int* const p?

Read right to left: p is a const pointer to a const int, meaning you can change neither the pointer nor the value it points to. Practising this right-to-left rule handles every combination.

Why do pointer-owning classes need a custom copy constructor?

Because the default copy is shallow and duplicates only the pointer value, leaving two objects sharing one allocation and risking a double free. A deep-copy constructor allocates fresh memory so the objects are independent.

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Related Articles

• C++ Programming Placement Questions, the master set
• C++ OOPs Interview Questions 2026, classes and virtual functions
• C++ STL Interview Questions 2026, containers and algorithms
• C Pointers Interview Questions 2026, pointers in C

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Confirm any pointer or memory semantics on the official cppreference documentation before your interview. This guide reflects candidate-reported patterns and public preparation resources as of June 2026.