Question

Possible Duplicate:
C++ Vector Pointers to Objects
Does std::list::remove method call destructor of each removed element?

If I have a std::vector defined as:

std::vector<Object*>* myObjects;

And then call:

delete myObjects;

Will the elements in myObjects then also be deleted? Is there any difference using an std::array or any other stl container?

Thanks in advance

Answer 1

No, and here’s why.

Consider these two cases:

int a, b, c;

auto stackvec = new vector<int*> { &a, &b, &c };
auto heapvec  = new vector<int*> { new int, new int, new int };

delete stackvec;
delete heapvec;

If calling delete on the vector*s called delete on the pointers they hold, then you’d be in for a heap of trouble (pun intended) because you’d be deleteing automatic variables with the first delete which yields undefined behaviour (a bad thing).

You have to manually iterate the vector and delete the pointers yourself when you know they’re dynamically allocated, or better, use std::unique_ptr and you never need to call delete on anything.

Also, you probably don’t need a pointer to a vector in the first place, but I won’t judge you since I don’t know your situation.

As for std::array and std::vector, you need to know the size of your std::array at compile time and you can’t resize it at runtime, but vector has neither of those restrictions.