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)