Shulou(Shulou.com)06/01 Report--

This article mainly introduces "how C++ uses constant expression functions to evaluate at compile time". In daily operation, I believe many people have doubts about how C++ uses constant expression functions to evaluate at compile time. I have consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful for you to answer the doubts about how C++ uses constant expression functions to evaluate at compile time. Next, please follow the editor to study!

T.123: evaluate at compile time using constant expression functions

Reason (reason)

A function is the most obvious and conventional way of expressing the computation of a value. Often a constexpr function implies less compile-time overhead than alternatives.

Function is the most obvious and convenient way to express evaluation. In general, constant expression functions require less compile-time cost than other options.

Note (Note)

"Traits" techniques are mostly replaced by template aliases to compute types and constexpr functions to compute values.

The "feature" technique has basically been replaced by template aliases when used to evaluate types, and can be replaced by constant expression functions when used in evaluation.

Example (sample)

Template

/ / requires Number

Constexpr T pow (T v, int n) / / power/exponential

{

T res = 1

While (nMurt -) res * = v

Return res

}

Constexpr auto f7 = pow (pi, 7)

Enforcement (implementation recommendations)

Flag template metaprograms yielding a value. These should be replaced with constexpr functions.

Template metaprogramming that returns a numeric value with the tag. It should be replaced by a constant expression function.

At this point, the study of "how C++ uses constant expression functions to evaluate at compile time" is over. I hope I can solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.