std::move_iterator

Defined in header `<iterator>`
template< class Iterator > class move_iterator;		(since C++11)

std::move_iterator is an iterator adaptor which behaves exactly like the underlying iterator (which must be at least an InputIterator), except that dereferencing converts the value returned by the underlying iterator into an rvalue. If this iterator is used as an input iterator, the effect is that the values are moved from, rather than copied from.

Member types

Member type	Definition
`iterator_type`	`Iterator`
`difference_type`	`std::iterator_traits<Iterator>::difference_type`
`pointer`	`Iterator`
`value_type`	`std::iterator_traits<Iterator>::value_type`
`iterator_category`	`std::iterator_traits<Iterator>::iterator_category`
`reference`	`value_type&&` (until C++17) If `std::iterator_traits<Iterator>::reference` is a reference, this is the rvalue reference version of the same type. Otherwise (such as if the wrapped iterator returns by value), this is `std::iterator_traits<Iterator>::reference` unchanged. (since C++17)

Member functions

(constructor)	constructs a new iterator adaptor (public member function)
operator=	assigns another iterator (public member function)
base	accesses the underlying iterator (public member function)
operator*operator->	accesses the pointed-to element (public member function)
operator[]	accesses an element by index (public member function)
operator++operator++(int)operator+=operator+operator--operator--(int)operator-=operator-	advances or decrements the iterator (public member function)

Member objects

Member name	Definition
`current` (private)	a copy of the base() iterator, the name is for exposition only

Non-member functions

operator==operator!=operator<operator<=operator>operator>=	compares the underlying iterators (function template)
operator+	advances the iterator (function template)
operator-	computes the distance between two iterator adaptors (function template)

Example

#include <iostream>
#include <algorithm>
#include <vector>
#include <iterator>
#include <numeric>
#include <string>
 
int main()
{
    std::vector<std::string> v{"this", "is", "an", "example"};
 
    std::cout << "Old contents of the vector: ";
    for (auto& s : v)
        std::cout << '"' << s << "\" ";
 
    typedef std::vector<std::string>::iterator iter_t;
    std::string concat = std::accumulate(
                             std::move_iterator<iter_t>(v.begin()),
                             std::move_iterator<iter_t>(v.end()),
                             std::string());  // Can be simplified with std::make_move_iterator
 
    std::cout << "\nConcatenated as string: " << concat << '\n'
              << "New contents of the vector: ";
    for (auto& s : v)
        std::cout << '"' << s << "\" ";
    std::cout << '\n';
}

Output:

Old contents of the vector: "this" "is" "an" "example"
Concatenated as string: thisisanexample
New contents of the vector: "" "" "" ""