[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.

A type X meets the Cpp17Iterator requirements if

  • X meets the Cpp17CopyConstructible, Cpp17CopyAssignable, Cpp17Swappable, and Cpp17Destructible requirements ([utility.arg.requirements], [swappable.requirements]), and
  • iterator_traits<X>​::​difference_type is a signed integer type or void, and
  • the expressions in Table 78 are valid and have the indicated semantics.

Table 78Cpp17Iterator requirements [tab:iterator]

Expression

Return type

Operational

Assertion/note

semantics

pre-/post-condition

*r

unspecified

Preconditions: r is dereferenceable.

++r

X&