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If you don't need dynamic growth and don't know the size of the buffer at compile time, when should unique_ptr<int[]> be used instead of vector<int> if at all?
Is there a significant performance loss in using vector instead of unique_ptr?
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(since C++11) std::unique_ptr is a smart pointer that owns and manages another object through a pointer and disposes of that object when the unique_ptr goes out of scope. The object is disposed of, using the associated deleter when either of the following happens: the managing unique_ptr object is destroyed.
Use unique_ptr when you want to have single ownership(Exclusive) of the resource. Only one unique_ptr can point to one resource. Since there can be one unique_ptr for single resource its not possible to copy one unique_ptr to another. A shared_ptr is a container for raw pointers.
Yes. Well the unique ptr has a function object that by default invokes delete on the pointed to object, which calls the destructor. You can change the type of that default deleter to do almost anything.
There is no performance loss in using std::vector vs. std::unique_ptr<int[]>. The alternatives are not exactly equivalent though, since the vector could be grown and the pointer cannot (this can be and advantage or a disadvantage, did the vector grow by mistake?)
There are other differences, like the fact that the values will be initialized in the std::vector, but they won't be if you new the array (unless you use value-initialization...).
At the end of the day, I personally would opt for std::vector<>, but I still code in C++03 without std::unique_ptr.
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