/* unspecified */ operator[]( difference_type n ) const; | (since C++11) (until C++17) | |
constexpr /* unspecified */ operator[]( difference_type n ) const; | (since C++17) |
Returns a reference to the element at specified relative location.
| n | - | position relative to current location |
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).
The return type is unspecified because the return type of the underlying iterator's operator[] is also unspecified (see LegacyRandomAccessIterator).
#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 << 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 (size_t t{0U}; 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"
|
(C++11)(C++11)(deprecated in C++20) | accesses the pointed-to element (public member function) |
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