What are the differences between constexpr and regular functions in C++?

What are the differences between constexpr and regular functions in C++?

In C++, constexpr functions are evaluated at compile time, while regular functions are evaluated at runtime. This can lead to performance improvements.

Can you give me an example of a constexpr function?

Sure! Here's a simple example:

constexpr int square(int x) {
    return x * x;
}

This function can be used in constant expressions.

Are there any limitations to using constexpr functions?

Yes, constexpr functions must have a return type and can only contain a single return statement in C++11. In later versions, they can be more complex.

When should I use constexpr instead of regular functions?

Use constexpr when you need compile-time evaluation for performance or when working with constant expressions. Regular functions are suitable for runtime calculations.