Iterator library

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C++ Reference
Language Concepts Utilities library Strings library Containers library Algorithms library Iterators library Numerics library Input/output library Localizations library Regular expressions library (C++11) Atomic operations library (C++11) Thread support library (C++11)
Iterator library
Iterator Concepts Iterator primitives iterator_traits input_iterator_tag output_iterator_tag forward_iterator_tag bidirectional_iterator_tag random_access_iterator_tag iterator Iterator adaptors reverse_iterator move_iterator (C++11) back_insert_iterator front_insert_iterator insert_iterator make_move_iterator (C++11) back_inserter front_inserter inserter Stream iterators istream_iterator ostream_iterator istreambuf_iterator ostreambuf_iterator Iterator operations advance distance prev (C++11) next (C++11) Range access begin (C++11) end (C++11)

Iterators are a generalization of pointers that allow C++ programs to access different containers in a uniform manner. Any algorithm that accepts iterators should accept regular pointers also.

Contents 1 Iterator Types 2 Iterator primitives 3 Iterator adaptors 4 Stream iterators 5 Iterator Operations 6 Range Access

[edit] Iterator Types

Five iterator categories are defined, according to operations defined on them:

Input iterator	allows reading from the iterator object allows iterating forward without multi-pass guarantee, i. e. reading the same element twice is not guaranteed to produce the same results
Output iterator	allows writing to the iterator object allows iterating forward without multi-pass guarantee
Forward iterator	allows reading from the iterator object allows iterating forward with multi-pass guarantee, i. e. reading the same element twice is guaranteed to produce the same results
Bidirectional iterator	allows reading from the iterator object allows iterating forward and backward with multi-pass guarantee
Random access iterator	allows reading from the iterator object allows iterating forward and backward randomly with multi-pass guarantee

Forward iterators satisfy the requirements of input iterators

This section is incomplete

[edit] Iterator primitives

iterator_traits	provides uniform interface to the properties of an iterator (class template)
input_iterator_tag output_iterator_tag forward_iterator_tag bidirectional_iterator_tag random_access_iterator_tag	empty class types used to indicate iterator categories (class)
iterator	the basic iterator (class template)

[edit] Iterator adaptors

reverse_iterator	iterator adaptor for reverse-order traversal (class template)
move_iterator (C++11)	iterator adaptor which dereferences to an rvalue reference (class template)
make_move_iterator (C++11)	creates a std::move_iterator of type inferred from the argument (function template)
back_insert_iterator	iterator adaptor for insertion at the end of a container (class template)
back_inserter	creates a std::back_insert_iterator of type inferred from the argument (function template)
front_insert_iterator	iterator adaptor for insertion at the front of a container (class template)
front_inserter	creates a std::front_insert_iterator of type inferred from the argument (function template)
insert_iterator	iterator adaptor for insertion into a container (class template)
inserter	creates a std::insert_iterator of type inferred from the argument (function template)

[edit] Stream iterators

istream_iterator	input iterator that reads from std::basic_istream (class template)
ostream_iterator	output iterator that writes to std::basic_ostream (class template)
istreambuf_iterator	input iterator that reads from std::basic_streambuf (class template)
ostreambuf_iterator	output iterator that writes to std::basic_streambuf (class template)

[edit] Iterator Operations

Defined in header <iterator>
advance	advances an iterator by given distance (function)
distance	returns the distance between two iterators (function)
next (C++11)	increment an iterator (function)
prev (C++11)	decrement an iterator (function)

[edit] Range Access

Defined in header <iterator>
begin (C++11)	returns an iterator to the beginning of a container or array (function)
end (C++11)	returns an iterator to the end of a container or array (function)