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

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

In C++, const defines a constant variable whose value cannot be changed, while constexpr indicates that the value can be evaluated at compile time.

Can you give me an example of each?

Sure! For const, you might have const int x = 10;. For constexpr, you could use constexpr int y = 20; which can be used in constant expressions.

Are there any performance differences between them?

Yes, constexpr can lead to better performance since it allows for compile-time evaluation, reducing runtime overhead.

When should I use one over the other?

Use const when you need a constant value that may not be known at compile time, and constexpr when you want to ensure compile-time evaluation.