std::rbegin, std::crbegin

Header: <array>

Returns an iterator to the reverse-beginning of the given range.

# Declarations

template< class C >
auto rbegin( C& c ) -> decltype(c.rbegin());

(since C++14) (constexpr since C++17)

template< class C >
auto rbegin( const C& c ) -> decltype(c.rbegin());

(since C++14) (constexpr since C++17)

template< class T, std::size_t N >
std::reverse_iterator<T*> rbegin( T (&array)[N] );

(since C++14) (constexpr since C++17)

template< class T >
std::reverse_iterator<const T*> rbegin( std::initializer_list<T> il );

(since C++14) (constexpr since C++17)

template< class C >
auto crbegin( const C& c ) -> decltype(std::rbegin(c));

(since C++14) (constexpr since C++17)

# Parameters

# Notes

The overload for std::initializer_list is necessary because it does not have a member function rbegin.

# Example

#include <iostream>
#include <iterator>
#include <vector>
 
int main()
{
    std::vector<int> v = {3, 1, 4};
    auto vi = std::rbegin(v); // the type of “vi” is std::vector<int>::reverse_iterator
    std::cout << "*vi = " << *vi << '\n';
 
    *std::rbegin(v) = 42; // OK: after assignment v[2] == 42
//  *std::crbegin(v) = 13; // error: the location is read-only
 
    int a[] = {-5, 10, 15};
    auto ai = std::rbegin(a); // the type of “ai” is std::reverse_iterator<int*>
    std::cout << "*ai = " << *ai << '\n';
 
    auto il = {3, 1, 4};
    // the type of “it” below is std::reverse_iterator<int const*>:
    for (auto it = std::rbegin(il); it != std::rend(il); ++it)
        std::cout << *it << ' ';
    std::cout << '\n';
}

# See also