std::move_iterator<Iter>::operator[]
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< cpp | iterator | move iterator
/* 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.
Contents |
[edit]Parameters
n | - | position relative to current location |
[edit]Return value
std::move(current
[n])(until C++20)ranges::iter_move(current
+ n)(since C++20)
[edit]Notes
The return type is unspecified because the return type of the underlying iterator's operator[] is also unspecified (see LegacyRandomAccessIterator). | (until C++20) |
[edit]Example
Run this code
#include <cstddef>#include <iomanip>#include <iostream>#include <iterator>#include <list>#include <string>#include <vector> void print(auto rem, constauto& v){for(std::cout<< rem;constauto& 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"
[edit]See also
accesses the pointed-to element (public member function) |