Overview over the iterator requirements of various algorithms

Question

Does anyone know of a source that gives an overview of the requirements regarding iterator_category posed by various algorithms in the C++ standard library? The documentation I've seen only gives the required iterator_category for each specific algorithm, not an overview of all algorithms.

Specifically, I am looking for cases where a bidirectional_iterator is needed where a forward_iterator wouldn't do.

Answer 1

Searching for "Bidirectional" in Clause 25 gives:

• std::copy_backward
• std::move_backward
• std::reverse
• std::reverse_copy
• std::stable_partition
• std::inplace_merge
• std::next_permutation
• std::prev_permutation

In general, you can consult the <algorithm> synopsis in §25.1 [algorithms.general] of the standard.

Answer 2

The standard lays out the requirements for the various iterators, with the relevant section being §24.2 [iterator.requirements].

As to your question specifically with regard to bidirectional iterators, they are required whenever it is necessary to move an iterator backwards, since they support every operation supported by forward iterators, in addition to:

--i
i--
*i--

As detailed here.