Hi everyone,
I recently went through a C++ developer interview and wanted to share the questions I was asked, grouped by topic. I hope this can help others preparing for similar interviews.
C++ Basics:
- Difference between references and pointers
- Stack vs. heap memory allocation
- Types of smart pointers
- How
unique_ptr ensures a single owner
- How
shared_ptr works and synchronizes the reference counter
- Copying or moving
unique_ptr
- Rvalue vs. lvalue
-
std::move and std::forward
OOP Concepts:
- Accessing private fields
- Multiple inheritance
- Static field initialization
- Throwing exceptions in constructors/destructors
- Virtual methods and destructors
- Abstract class vs. interface
- Can constructors be virtual?
- Using
const for class methods
- Preventing object copying
STL Containers:
- Differences between
vector and list
-
map vs. unordered_map
- Iterator invalidation on
push_back()
- Modifying classes for use in
map/unordered_map
Threads & Concurrency:
- Processes vs. threads
- Can the same thread run twice?
- Thread synchronization methods
- Deadlocks
I’m curious if there are other commonly asked c++ interview questions that I should prepare for, especially for mid-level or advanced roles. Any tips or additional topics would be helpful.
From my experience interviewing and working with C++ developers, c++ interview questions usually begin with the fundamentalsbut not in a shallow way. Interviewers expect you to clearly explain differences like pointers vs references, stack vs heap allocation, and why smart pointers exist in the first place. It’s important to talk about ownership models (unique_ptr vs shared_ptr), RAII principles, and how memory management choices impact performance, safety, and scalability in real-world systems, not just toy examples.
Building on that, once the basics are covered, interviews tend to move into design-oriented c++ interview questions, especially around OOP. In my experience, it’s not enough to define concepts like virtual methods, abstract classes, or multiple inheritance. Strong candidates explain why and when to use them, how const correctness improves API reliability, and how access control protects invariants. Interviewers often listen for reasoning around maintainability, extensibility, and clean design rather than textbook definitions.
To take it a step further, more advanced c++ interview questions often test how well you apply this knowledge under real constraints. STL container choices (vector vs list, map vs unordered_map), iterator invalidation, and threading concepts like synchronization, deadlocks, and race conditions come up frequently. What really stands out is when candidates share practical examples why a container was chosen, how performance bottlenecks were avoided, or how concurrency bugs were diagnosed and fixed in production systems.