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This article mainly introduces "how to define constexpr in C++". In daily operation, I believe many people have doubts about how to define constexpr in C++. Xiaobian consulted various materials and sorted out simple and easy operation methods. I hope to help you answer the doubts of "how to define constexpr in C++"! Next, please follow the small series to learn together!

If the function is likely to need compile-time evaluation, define it as constexprReason

constexpr is needed to tell the compiler to allow compile-time evaluation.

You want to tell the compiler that constexpr is required to allow compile-time computation.

Example

The (in)famous factorial:

The following is a (non) famous factorial algorithm:

constexpr int fac(int n){ constexpr int max_exp = 17; // constexpr enables max_exp to be used in Expects Expects(0

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