Difference between revisions of "cpp/iterator/reverse iterator/reverse iterator"

#include <cassert>
#include <concepts>
#include <iterator>
#include <vector>
 
int main()
{
    std::vector v{0, 1, 2, 3, 4};
 
    using ReverseIt = std::reverse_iterator<std::vector<int>::const_iterator>;
 
    ReverseIt i1; // overload (1)
    i1 = v.crbegin();
    assert(*i1 == 4);
 
    ReverseIt i2(i1); // overload (2)
    assert(i2[0] == 4);
 
    int x[]{1, 2, 3};
    auto i3 = std::reverse_iterator<int*>(x + std::size(x)); // overload (1)
    i3[0] = -3;
    assert(x[2] == -3);
    std::reverse_iterator<int const*> i4(i3); // overload (3): int => const int
    static_assert(std::convertible_to<decltype(i3)::value_type,
                                      decltype(i4)::value_type>);
    // i4[0] = 5; // Error: assignment of read-only location
}