I'm leaking bytes!

What this C++ memory-management interview question tests

This is a medium-difficulty C++ question that quant firms use to assess whether a candidate can trace heap allocations and spot resource-leakage bugs by reading code. It requires careful attention to object lifetimes, constructor and destructor calls, and the ownership semantics of pointers.

To solve problems like this, you need to step through the code mentally, count every new call and equivalent allocation, and then verify that each allocation has a corresponding delete or is owned by a stack-based container (like std::unique_ptr or std::vector) that will clean it up. Common pitfalls include forgetting that exceptions can bypass cleanup paths, misunderstanding when destructors run, and missing implicit allocations inside standard library calls.

• Heap vs. stack allocation
• Ownership and lifetime rules for raw pointers
• RAII and smart pointers as leak prevention
• Exception safety and cleanup paths