What is std::weak_ptr in C++11?

Can you explain what std::weak_ptr is in C++11?

Sure! std::weak_ptr is a smart pointer in C++11 that holds a non-owning reference to an object managed by std::shared_ptr.

How does std::weak_ptr help with memory management?

It helps prevent circular references that can lead to memory leaks by allowing you to reference an object without owning it.

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;
    } else {
        std::cout << "Weak pointer is expired" << std::endl;
    }
}

This code demonstrates creating a weak pointer from a shared pointer.

What happens if the shared_ptr is deleted?

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