What are some examples of using unique pointers in C++?

Can you explain what a unique pointer is in C++?

A unique pointer is a smart pointer that owns a dynamically allocated object exclusively. It ensures that there is only one unique pointer to a resource, preventing memory leaks.

Can you give me some examples of how to use unique pointers?

Sure! 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 unique pointer?

You cannot copy a unique pointer because it is designed to have exclusive ownership. If you try to copy it, you'll get a compilation error. You can, however, transfer ownership using std::move().

Can you show me an example of transferring ownership?

Absolutely! Here's how you can transfer ownership:

#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)); // Transfers ownership to display function
    // ptr1 is now nullptr
    return 0;
}