What is the purpose of if constexpr in C++17?

Can you explain what if constexpr does in C++17?

Sure! The if constexpr statement allows for compile-time conditional branching, enabling more flexible template programming.

How does it differ from regular if statements?

Unlike regular if statements, if constexpr is evaluated at compile time, which can lead to better optimization and error checking.

Can you give me an example of how to use it?

Certainly! Here's a simple example:

template<typename T>
void func(T value) {
    if constexpr (std::is_integral_v<T>) {
        std::cout << "Integer: " << value;
    } else {
        std::cout << "Not an integer: " << value;
    }
}

What happens if the condition is false?

If the condition is false, the code inside that branch is not compiled, preventing any errors related to that branch.