std::move_iterator<Iter>::operator[]
/* unspecified */ operator[]( difference_type n ) const; |
(constexpr 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
std::move(current [n])(until C++20)ranges::iter_move(current +n)(since C++20)
Notes
| The return type is unspecified because the return type of the underlying iterator's operator[] is also unspecified (see LegacyRandomAccessIterator). | (until C++20) |
Example
#include <cstddef>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <string>
#include <vector>
void print(auto rem, const auto& v)
{
for (std::cout << rem; const auto& 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
| accesses the pointed-to element (public member function) |
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