Summing a pool-allocated vector

What this C++ memory-management question tests

This is a medium-difficulty question that probes your understanding of how C++ handles object lifecycle, memory allocation, and scope in a practical code-reading context. Rather than asking you to write code from scratch, it challenges you to predict runtime behaviour—a skill that separates candidates who can reason about their code from those who merely write it.

The question rewards careful attention to allocation strategy, constructor and destructor semantics, and how memory pools interact with stack scope. You'll need to trace the flow of object creation and destruction to determine what the program actually does, including whether it runs successfully, crashes, or produces undefined behaviour. This mirrors the diagnostic reasoning that production debugging demands.

• Custom allocators and memory pools
• Object lifetime and automatic cleanup
• Scope-based resource management
• Undefined behaviour detection