What are some examples of constexpr in C++?

What are some examples of constexpr in C++?

In C++, constexpr is used to indicate that a function or variable can be evaluated at compile time. For example, you can define a constant expression like this:

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

You can then use this function in a context that requires a compile-time constant.

Can you give me a more complex example?

Sure! Here's a more complex example using constexpr with a template:

template<int N>
constexpr int factorial() {
    return N * factorial<N - 1>();
}

template<> 
constexpr int factorial<0>() { return 1; }

You can call factorial<5>() at compile time to get the value 120.

What are the benefits of using constexpr?

Using constexpr can lead to performance improvements since computations can be done at compile time, reducing runtime overhead. It also helps in writing safer and more predictable code.

Are there any limitations to constexpr?

Yes, there are some limitations. For instance, constexpr functions cannot contain certain statements like try or catch, and they must have a return type that can be evaluated at compile time.