What is the difference between constexpr and const in C++20?

What is the difference between constexpr and const in C++20?

In C++20, constexpr allows for compile-time evaluation of functions and variables, while const simply indicates that a variable's value cannot be changed after initialization.

Can you give me an example of when to use constexpr?

Sure! You would use constexpr when you want to define a function that can be evaluated at compile time, like calculating a factorial.

Are there any limitations to using constexpr?

Yes, constexpr functions must have a return type and cannot contain any statements that would cause runtime evaluation, like dynamic memory allocation.

How does constexpr improve performance?

By allowing computations to be done at compile time, constexpr can reduce runtime overhead, leading to faster execution.