C++: std::optional vs nullptr

What is the difference between std::optional and nullptr in C++?

std::optional is a type that can hold a value or indicate absence, while nullptr is a null pointer constant.

When should I use std::optional instead of nullptr?

Use std::optional when you want to express that a value may or may not be present, providing better type safety.

Can you give an example of using std::optional?

Sure! Here's a simple example:

std::optional<int> getValue(bool returnValue) {
    if (returnValue) {
        return 42;
    }
    return std::nullopt;
}

This function returns an optional integer.

Are there performance implications when using std::optional?

Yes, std::optional may have a slight overhead compared to raw pointers, but it provides safety and clarity in your code.