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c++stdmaperase
Gevorg Adamyan
Gevorg Adamyan

Reputation: 111

Why map.erase returns iterator?

I've want to erase the elements of the std::map from beginIt to endIt. erase function returns the iterator to the element that follows the last element removed. isn't it endIt ? Why the erase returns iterator ?

auto it = m_map.erase(beginIt, endIt);

Upvotes: 7

Views: 2306

Answers (2)

Bathsheba
Bathsheba

Reputation: 234715

It's a useful feature that the C++ standard library adopts for all its containers.

One good use in particular is when you are deleting a set of elements subject to a constraint and you are iterating over the whole container. Obviously deleting something from a container invalidates the iterator that you passed. To return the next candidate iterator is useful.

Upvotes: 9

kmdreko
kmdreko

Reputation: 60052

I believe this is due to trying to unify function calls across the standard container types. For example, in an std::vector the returned iterator is not the same as endIt

Upvotes: 2

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