Iterator Concepts

From Cppreference

C++ Standard Library
Language 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 operations advance distance prev next Predefined operators Stream iterators Range access begin (C++11) end (C++11)

Contents 1 Notation 2 Iterator Requirements 3 InputIterator Requirements 4 OutputIterator Requirements 5 ForwardIterator Requirements 6 BidirectionalIterator Requirements 7 RandomAccessIterator Requirements

[edit] Notation

In the following, as in the standard, the following notation is used:

• X is the iterator type being discussed
• a and b are instances of the iterator, with type X
• reference refers to iterator_traits<X>::reference
• difference_type refers to iterator_traits<X>::difference_type

[edit] Iterator Requirements

Iterator is a general concept that does not guarantee much beyond the ability to advance and dereference elements. Formally, an iterator has the following requirements:

• CopyConstructable
• CopyAssignable
• Destructible
• Swappable

In addition, the following expressions are valid:

• *a returns type reference as long as the itearator is dereferencable.
• ++a returns X&

Examples:

• All iterators in the standard library model the Iterator concept.

[edit] InputIterator Requirements

[edit] OutputIterator Requirements

[edit] ForwardIterator Requirements

[edit] BidirectionalIterator Requirements

[edit] RandomAccessIterator Requirements