Reusing a pool across scopes

Understanding object lifetime and scope in C++ memory pools

This hard C++ question tests your ability to reason about object construction, destruction, and scope when custom memory management is involved. It requires precise knowledge of how lifetimes interact with pool-based allocation strategies—a critical skill when writing low-latency systems where allocator behaviour must be predictable.

To answer correctly, you need to trace the order of constructor and destructor calls as objects enter and exit scope, and understand how a pool's reuse mechanism affects the state of previously-allocated memory. The question rewards candidates who can mentally execute the code and predict output without ambiguity, catching subtle interactions between scope rules and custom allocator semantics.

• Constructor and destructor invocation order
• Stack vs. heap lifetime semantics
• Memory reuse and object state across allocation cycles
• RAII and scope guards in C++