std::move_iterator<Iter>::operator[]

/* unspecified */ operator[]( difference_type n ) const;

constexpr reference operator[]( difference_type n ) const;

返回指定相对位置的元素的引用。

参数

返回值

std :: move ( current  [ n ] ) (C++20 前) ranges:: iter_move ( current + n ) (C++20 起)

注释

示例

#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
}

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

参见