Struct Layout Calculator

Understanding C++ struct memory layout and padding

This easy coding problem tests your knowledge of how C++ compilers physically arrange struct members in memory. It is a practical skill for systems programming, low-latency trading systems, and any codebase where cache efficiency or binary protocol compatibility matters.

The problem asks you to simulate the compiler's layout algorithm: stepping through members in order, inserting padding to satisfy each member's alignment requirement, and then adding trailing padding so the struct size is a multiple of the strictest alignment. The challenge is not algorithmic complexity but rather careful bookkeeping and understanding the rules precisely. Interviewers often use this to confirm that a candidate can reason about low-level memory layout without relying on tooling like sizeof() or #pragma pack.

• Alignment and address arithmetic
• Padding insertion logic
• Struct size calculation with trailing padding
• Why member order affects memory footprint and cache behavior