C++ unique_ptr Usage Guide

unique_ptr is a smart pointer class used to manage ownership of dynamically allocated objects. Unlike traditional raw pointers, unique_ptr automatically releases the object it manages, preventing memory leaks.

The usage of unique_ptr is as follows:

1. Create a unique_ptr object: You can use the std::make_unique function to create a unique_ptr object and point it to a dynamically allocated object.

std::unique_ptr<int> ptr = std::make_unique<int>(10);

1. Access the object pointed to by the unique_ptr: You can access the object pointed to by the unique_ptr using either the arrow operator or the * operator.

std::cout << *ptr << std::endl;

1. Transferring ownership: unique_ptr does not allow copying or assigning operations, but you can use the std::move function to transfer its ownership to another unique_ptr object.

std::unique_ptr<int> ptr2 = std::move(ptr);

1. Manually releasing objects: unique_ptr automatically releases the object it manages at the end of its lifetime, but it can also be manually released.

ptr2.reset();

1. Customizing deleters using lambda expressions: You can use lambda expressions to customize deleters in order to perform specific operations when releasing objects.

std::unique_ptr<int, std::function<void(int*)>> ptr3(new int(20), [](int* p){ std::cout << "Deleting: " << *p << std::endl; delete p; });