Keep your cool, keep it constant.

Understanding constant expressions in C++

This easy question tests your knowledge of C++ compile-time evaluation and the constexpr keyword. It asks you to read a code snippet and determine whether a given value qualifies as a constant expression—that is, whether the compiler can evaluate it during compilation rather than at runtime.

Recognising constant expressions is foundational for writing efficient C++ code, especially in performance-critical domains like quantitative trading. The distinction between compile-time and runtime evaluation affects code optimisation, template instantiation, and the ability to use values in array dimensions or template arguments. You'll need to understand which operations and contexts permit compile-time evaluation, and how compiler rules for constants differ from ordinary variables.

• The role of constexpr in signalling compile-time intent
• Literal types and their constraints
• Operations and control flow allowed in constant expressions
• The difference between constant values and constant expressions