Annotating members of different sizes

Understanding memory layout and alignment in C++

This medium-difficulty question tests your knowledge of how C++ lays out class members in memory and applies alignment rules to structures of different sizes. It is commonly asked in interviews for roles requiring low-level systems work, such as high-frequency trading infrastructure or embedded systems, where memory efficiency and predictable object layout matter.

To answer correctly, you need to reason about padding, alignment boundaries, and how the compiler orders struct members. The question rewards candidates who can visualize memory layouts without running code and understand why certain arrangements waste space or align to particular offsets.

• Struct member ordering and padding
• Alignment requirements for primitive types
• Size of a class or struct in memory
• How different member sizes force alignment gaps