Using unique_ptr to uniquely own a memory resource

Manual handling of heap memory allocation and releasing it (with new and delete) is one of the most controversial features of C++. All allocations must be properly paired with a corresponding delete operation in the correct scope. If the memory allocation is done in a function and needs to be released before the function returns, for instance, then this has to happen on all the return paths, including the abnormal situation where a function returns because of an exception. C++11 features, such as rvalues and move semantics, have enabled the development of better smart pointers (since some, such as auto_ptr, existed prior to C++11); these pointers can manage a memory resource and automatically release it when the smart pointer is destroyed. In this recipe, we will look at std::unique_ptr, a smart pointer that owns and manages another object or an array of objects allocated on the heap, and performs the disposal operation when the smart...