The Empty Seat

What this hard C++ memory-layout question tests

This is a hard C++ question that probes deep understanding of how compilers arrange data in memory. It rewards knowledge of alignment requirements, padding rules, and the subtle interaction between struct layout and platform-specific constraints—exactly what high-frequency trading systems depend on for correctness and predictable performance.

To solve problems like this, you need to reason carefully about alignment rules for each member, predict where the compiler will insert padding bytes, and account for the size and alignment of the struct as a whole. The question tests whether you can mentally execute the layout algorithm without running code—a skill that separates candidates who understand the machine from those who merely use it.

• Struct member alignment and padding
• The role of the largest member in determining struct alignment
• Platform-dependent size and offset calculations
• How sizeof and alignment guarantees interact