What are the best practices for using constexpr in C++20?

What are the best practices for using constexpr in C++20?

In C++20, best practices for using constexpr include ensuring that functions are simple, avoiding side effects, and using constexpr for both functions and variables.

Can you give an example of a constexpr function?

Sure! Here's a simple example:

constexpr int factorial(int n) {
    return n <= 1 ? 1 : n * factorial(n - 1);
}

This function computes the factorial of a number at compile time.

What are the limitations of constexpr in C++20?

In C++20, while constexpr has expanded, it still cannot include certain operations like dynamic memory allocation or I/O operations.

How does constexpr improve performance?

constexpr allows computations to be done at compile time, reducing runtime overhead and improving performance by eliminating unnecessary calculations.