Can you explain unique pointers in C++ with examples?

Can you explain unique pointers in C++ with examples?

Sure! Unique pointers are smart pointers in C++ that ensure a single ownership of a dynamically allocated object. They automatically deallocate the memory when the unique pointer goes out of scope.

Can you show me a simple example of how to use a unique pointer?

Absolutely! Here's a basic 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;
}

In this example, ptr is a unique pointer that points to an integer with a value of 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 explain how to transfer ownership with an example?

Sure! 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)); // Ownership is transferred to the display function
    // ptr1 is now nullptr
    return 0;
}

In this example, ptr1 is moved to the display function, transferring ownership.