Signed Integer Overflow

What this C++ integer overflow question tests

This is an easy language-knowledge question that probes understanding of how C++ handles signed integer arithmetic at the boundaries of representable values. Quant firms ask it to verify that candidates grasp the formal semantics of the language they code in—a crucial foundation for writing reliable systems code.

The question asks you to reason about what happens when a signed integer operation crosses into undefined or implementation-defined territory. Success requires knowing the relevant parts of the C++ standard, distinguishing between well-defined and ill-defined behaviour, and recognising when a compiler might optimise based on assumptions about valid program state.

• Signed vs. unsigned integer semantics
• The C++ standard's guarantees and gaps
• Compiler optimisation and undefined behaviour
• Debugging overflow issues in production code