Member Order

Understanding memory layout and alignment in C++

This medium-difficulty C++ question tests your grasp of struct member ordering, padding, and alignment requirements—concepts that matter deeply in performance-critical code like trading systems where cache efficiency and memory footprint directly affect latency.

To answer correctly, you need to trace how a compiler arranges struct members in memory, accounting for alignment constraints on a platform with 4-byte integers and 4-byte alignment. The question rewards you for understanding not just what gets printed, but why: how the compiler satisfies alignment rules, where padding bytes appear, and what that means for the final layout.

• Alignment requirements and alignof
• Struct member packing and padding
• Platform-dependent memory layout
• Size and offset calculations