What are some examples of using std::unique_ptr in C++17?

Can you show me some examples of using std::unique_ptr in C++17?

Sure! std::unique_ptr is a smart pointer that manages a dynamically allocated object. Here's a simple example:

#include <iostream>
#include <memory>

int main() {
    std::unique_ptr<int> ptr = std::make_unique<int>(10);
    std::cout << *ptr << std::endl; // Outputs: 10
    return 0;
}

This creates a unique pointer to an integer initialized to 10.

What happens if I try to copy a std::unique_ptr?

You cannot copy a std::unique_ptr because it is designed to have sole ownership of the object it points to. If you try to copy it, you'll get a compilation error. Instead, you can move it using std::move().

Can you give me an example of moving a std::unique_ptr?

Absolutely! Here's how you can move a std::unique_ptr:

#include <iostream>
#include <memory>

void display(std::unique_ptr<int> ptr) {
    std::cout << *ptr << std::endl;
}

int main() {
    std::unique_ptr<int> ptr1 = std::make_unique<int>(20);
    display(std::move(ptr1)); // ptr1 is now empty
    return 0;
}

In this example, ptr1 is moved to the display function, leaving ptr1 empty.

Are there any performance benefits to using std::unique_ptr?

Yes, using std::unique_ptr can improve performance by eliminating the overhead of reference counting found in shared pointers. It also ensures that resources are automatically released when the unique pointer goes out of scope, reducing memory leaks.