2.4 KiB
[iterator.iterators]
24 Iterators library [iterators]
24.3 Iterator requirements [iterator.requirements]
24.3.5 C++17 iterator requirements [iterator.cpp17]
24.3.5.2 Cpp17Iterator [iterator.iterators]
The Cpp17Iterator requirements form the basis of the iterator taxonomy; every iterator meets the Cpp17Iterator requirements.
This set of requirements specifies operations for dereferencing and incrementing an iterator.
Most algorithms will require additional operations to read ([input.iterators]) or write ([output.iterators]) values, or to provide a richer set of iterator movements ([forward.iterators], [bidirectional.iterators], [random.access.iterators]).
A type X meets the Cpp17Iterator requirements if
X meets the Cpp17CopyConstructible, Cpp17CopyAssignable, Cpp17Swappable, andCpp17Destructible requirements ([utility.arg.requirements], [swappable.requirements]), and
iterator_traits::difference_type is a signed integer type or void, and
the expressions in Table 78 are valid and have the indicated semantics.
Table 78 — Cpp17Iterator requirements [tab:iterator]
| ð Expression |
Return type | Operational | Assertion/note |
|---|---|---|---|
| ð | semantics | pre-/post-condition | |
| ð *r |
unspecified | Preconditions: r is dereferenceable. | |
| ð ++r |
X& |