What are some practical examples of constexpr in modern C++?

What are some practical examples of constexpr in modern C++?

In modern C++, constexpr allows you to evaluate functions at compile time. For example, you can define a constexpr function to calculate the factorial of a number.

Can you show me a code snippet for that?

Sure! Here's a simple example:

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

How can I use this in a real program?

You can use constexpr functions to initialize constant values at compile time, improving performance. For instance, you can use it to define array sizes or template parameters.

Are there any limitations to using constexpr?

Yes, constexpr functions must have a single return statement and cannot contain any side effects. They also can't use dynamic memory allocation.