What is std::weak_ptr in C++?

Can you explain what std::weak_ptr is in C++?

Sure! std::weak_ptr is a smart pointer in C++ that holds a non-owning reference to an object managed by std::shared_ptr.

Why would I use std::weak_ptr instead of std::shared_ptr?

You use std::weak_ptr to prevent circular references that can lead to memory leaks, as it doesn't increase the reference count.

Can you give me an example of how to use std::weak_ptr?

Certainly! Here's a simple example:

#include <iostream>
#include <memory>

class MyClass {
public:
    MyClass() { std::cout << "MyClass created" << std::endl; }
    ~MyClass() { std::cout << "MyClass destroyed" << std::endl; }
};

int main() {
    std::shared_ptr<MyClass> sharedPtr = std::make_shared<MyClass>();
    std::weak_ptr<MyClass> weakPtr = sharedPtr;
    if (auto tempPtr = weakPtr.lock()) {
        std::cout << "Weak pointer is valid" << std::endl;
    }
    return 0;
}

What happens if the object is deleted while using std::weak_ptr?

If the object is deleted, the std::weak_ptr becomes expired, and calling lock() will return a nullptr.