Measuring two structure arrays

What this C++ struct-memory interview question tests

This is a hard C++ language-knowledge question that probes your understanding of memory layout, data alignment, and padding in compiled code. Quant firms and systems-focused tech companies use questions like this to verify that candidates can reason about low-level details that affect both correctness and performance in latency-critical systems.

Working through this kind of problem requires you to trace how a compiler arranges struct members in memory, account for alignment requirements imposed by the CPU architecture, and predict the actual size and offset of each field. The gap between your intuition and the actual output often reveals misconceptions about how modern C++ implementations handle storage.

• Alignment and padding rules across different architectures
• Struct member ordering and its impact on total size
• Using sizeof and pointer arithmetic to inspect memory layout
• Platform-specific behaviour and compiler flags