It's a simple struct.

What this C++ struct-size interview question tests

This is an easy C++ question that probes whether you understand memory layout, alignment rules, and how the compiler packs data members into structs on a 64-bit architecture. Quant firms ask questions like this to confirm that candidates have concrete knowledge of low-level behavior rather than relying on intuition.

To answer correctly, you need to know how the compiler aligns individual member types, how padding works, and whether any special attributes or packing directives are in play. The question rewards careful observation of the actual struct definition and application of standard C++ alignment rules.

• Fundamental type sizes and alignment requirements
• Padding and struct member ordering
• 64-bit architecture conventions
• Compiler packing behavior