CONCEPT OUTPUTITE(7)

NAME
OutputIterator

DESCRIPTION

An output iterator is an iterator that can write a sequence of values. It is single-pass (old values of the iterator cannot be re-used), and write-only.

An output iterator represents a position in a (possibly infinite) sequence. Therefore, the iterator can point into the sequence (returning a value when dereferenced and being incrementable), or be off-the-end (and not dereferenceable or incrementable).

ASSOCIATED TYPES

    &#8226; value_type

    std::iterator_traits<Iter>::value_type
    The stated value type of the iterator (should be void for an output iterator that does not model some other iterator concept).

    &#8226; difference_type

    std::iterator_traits<Iter>::difference_type
    The difference type of the iterator

    &#8226; category

    std::iterator_traits<Iter>::iterator_category
    The category of the iterator

NOTATION

Iter
    A type playing the role of iterator-type in the OutputIterator concept.

ValueType
    A type playing the role of value-type in the OutputIterator concept.

i, j
    Objects of type Iter

x
    Object of type ValueType

TYPE EXPRESSIONS

    The type Iter must be a model of Assignable.

    The type ValueType must be a model of Assignable.

    The type Iter must be a model of DefaultConstructible.

    The type Iter must be a model of EqualityComparable.

Category tag
    category must be derived from std::output_iterator_tag, a model of DefaultConstructible, and a model of CopyConstructible.

Difference type properties
    difference_type must be a model of SignedInteger.

VALID EXPRESSIONS
Name | Expression | Type | Precondition | Semantics | Postcondition
Dereference | *i |  | i is incrementable (not off-the-end) |  |
Dereference and assign | *i = x |  | i is incrementable (not off-the-end) |  | *i may not be written to again until it has been incremented.
Preincrement | ++i | Iter & | i is incrementable (not off-the-end) |  |
Postincrement | i++ |  | i is incrementable (not off-the-end) | Equivalent to (void)(++i) | i is dereferenceable or off-the-end
Postincrement, dereference, and assign | *i++ = x |  | i is incrementable (not off-the-end) | Equivalent to {*i = t; ++i;} | i is dereferenceable or off-the-end

COMPLEXITY

All iterator operations must take amortized constant time.

MODELS

    &#8226; std::ostream_iterator, ...

    &#8226; std::insert_iterator, ...

    &#8226; std::front_insert_iterator, ...

    &#8226; std::back_insert_iterator, ...