NAME¶

std::move_iterator::operator[] - std::move_iterator::operator[]

Synopsis¶

/* unspecified */ operator[]( difference_type n ) const; (since C++11)
(until C++17)
constexpr /* unspecified */ operator[]( difference_type n ) const; (since C++17)
(until C++20)
constexpr reference operator[]( difference_type n ) const; (since C++20)

Returns a reference to the element at specified relative location.

Parameters¶

n - position relative to current location

Return value¶

An rvalue reference to the element at relative location, that is,
std::move(base()[n])
(until C++20)
ranges::iter_move(base() + n)
(since C++20).

Notes¶

The return type is unspecified because the return type of the
underlying iterator's operator[] is also unspecified (see (until C++20)
LegacyRandomAccessIterator).

Example¶

// Run this code

#include <cstddef>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <string>
#include <vector>

void print(auto rem, auto const& v)
{
for (std::cout << rem; auto const& e : v)
std::cout << std::quoted(e) << ' ';
std::cout << '\n';
}

int main()
{
std::vector<std::string> p{"alpha", "beta", "gamma", "delta"}, q;
print("1) p: ", p);

std::move_iterator it{p.begin()};

for (std::size_t t{}; t != p.size(); ++t)
q.emplace_back(it[t]);

print("2) p: ", p);
print("3) q: ", q);

std::list l{1, 2, 3};
std::move_iterator it2{l.begin()};
// it2[1] = 13; // compilation error: the underlying iterator
// does not model the random access iterator
// *it2 = 999; // compilation error: using rvalue as lvalue
}

Possible output:¶

1) p: "alpha" "beta" "gamma" "delta"
2) p: "" "" "" ""
3) q: "alpha" "beta" "gamma" "delta"

See also¶

operator*
operator-> accesses the pointed-to element
(C++11) (public member function)
(C++11)(deprecated in C++20)