What is a weak_ptr in C++?

What is a weak_ptr in C++?

A weak_ptr is a smart pointer in C++ that holds a non-owning reference to an object managed by a shared_ptr. It helps prevent circular references.

How does weak_ptr help with memory management?

It allows you to observe an object without taking ownership, which helps avoid memory leaks caused by circular references between shared_ptrs.

Can you give me an example of using weak_ptr?

Sure! Here's a simple example:

#include <iostream>
#include <memory>

class Node {
public:
    std::shared_ptr<Node> next;
};

int main() {
    std::shared_ptr<Node> node1 = std::make_shared<Node>();
    std::weak_ptr<Node> weakNode = node1;
    
    if (auto sharedNode = weakNode.lock()) {
        std::cout << "Node is still alive!" << std::endl;
    }
    return 0;
}

What happens if the shared_ptr is deleted?

If the shared_ptr is deleted, the weak_ptr will no longer be able to lock to a valid shared_ptr, and any attempt to access it will return a null pointer.