How do I use weak_ptr in C++11?

How do I use weak_ptr in C++11?

In C++11, weak_ptr is used to prevent circular references in shared_ptr. It allows you to reference an object managed by shared_ptr without increasing its reference count.

Can you give me an example of how to implement weak_ptr?

Sure! Here's a simple example:

#include <iostream>
#include <memory>

class Node {
public:
    std::shared_ptr<Node> next;
    Node() { std::cout << "Node created" << std::endl; }
    ~Node() { std::cout << "Node destroyed" << std::endl; }
};

int main() {
    std::shared_ptr<Node> node1 = std::make_shared<Node>();
    std::weak_ptr<Node> weakNode = node1;
    std::cout << "Weak pointer use count: " << weakNode.use_count() << std::endl;
    return 0;
}

What happens if the shared_ptr is deleted?

If the shared_ptr is deleted, the weak_ptr will not prevent the object from being destroyed. The weak_ptr will become expired, and you can check this using the expired() method.

Are there any performance considerations when using weak_ptr?

Yes, using weak_ptr can introduce some overhead due to the need to manage the reference count. However, it is generally minimal compared to the benefits of avoiding memory leaks.