std::reverse_iterator::reverse_iterator - cppreference.com (original) (raw)

reverse_iterator(); (1) (constexpr since C++17)
explicit reverse_iterator( iterator_type x ); (2) (constexpr since C++17)
template< class U >reverse_iterator( const reverse_iterator<U>& other ); (3) (constexpr since C++17)

Constructs a new reverse_iterator.

Overload current
(1) value-initialized
(2) initialized with x
(3) initialized with other.current
  1. The converting constructor.

[edit] Parameters

x - iterator to adapt
other - iterator adaptor to copy

[edit] Example

#include #include #include #include   int main() { std::vector v{0, 1, 2, 3, 4};   using ReverseIt = std::reverse_iterator<std::vector::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 }

[edit] Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR Applied to Behavior as published Correct behavior
LWG 235 C++98 the effect of overload (1) was not specified specified
LWG 1012 C++98 overload (1) default-initialized current it is value-initialized
LWG 3435 C++20 overload (3) was not constrained constrained

[edit] See also