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std::reverse_iterator::base(3) C++ Standard Libary std::reverse_iterator::base(3)

NAME

std::reverse_iterator::base - std::reverse_iterator::base

Synopsis


iterator_type base() const; (until C++17)
constexpr iterator_type base() const; (since C++17)


Returns the underlying base iterator. That is std::reverse_iterator(it).base() ==
it.


The base iterator refers to the element that is next (from the
std::reverse_iterator::iterator_type perspective) to the element the
reverse_iterator is currently pointing to. That is &*(rit.base() - 1) == &*rit.

Parameters


(none)

Return value


The underlying iterator.

Exceptions


May throw implementation-defined exceptions.

Example

// Run this code


#include <iostream>
#include <iterator>
#include <vector>


int main()
{
std::vector<int> v = {0, 1, 2, 3, 4, 5};


using RevIt = std::reverse_iterator<std::vector<int>::iterator>;


const auto it = v.begin() + 3;
RevIt r_it{it};


std::cout << "*it == " << *it << '\n'
<< "*r_it == " << *r_it << '\n'
<< "*r_it.base() == " << *r_it.base() << '\n'
<< "*(r_it.base()-1) == " << *(r_it.base() - 1) << '\n';


RevIt r_end{v.begin()};
RevIt r_begin{v.end()};


for (auto it = r_end.base(); it != r_begin.base(); ++it)
std::cout << *it << ' ';
std::cout << '\n';


for (auto it = r_begin; it != r_end; ++it)
std::cout << *it << ' ';
std::cout << '\n';
}

Output:


*it == 3
*r_it == 2
*r_it.base() == 3
*(r_it.base()-1) == 2
0 1 2 3 4 5
5 4 3 2 1 0

See also


operator* accesses the pointed-to element
operator-> (public member function)

2024.06.10 http://cppreference.com