C++ Array Library - rbegin() Function

Description

The C++ function std::array::rbegin() returns an reverse iterator pointing to the last element of the array.

Declaration

Following is the declaration for std::array::rbegin() function form std::array header.

reverse_iterator rbegin() noexcept;
const_reverse_iterator rbegin() const noexcept;

Parameters

None

Return Value

Return a reverse iterator which points to the last element of the array. Iterator return by this method is just a right before element which would be pointed by member function end. In other words it returns a reverse iterator which points to the first element of the reversed array container.

If array object is const-qualified, the method returns const reverse iterator otherwise returns reverse iterator.

Exceptions

This member function never throws exception.

Time complexity

Constant i.e. O(1)

Example

The following example shows the usage of std::array::rbegin() function.

#include <iostream>
#include <array>

using namespace std;

int main(void) {

   array<int, 5> arr = {10, 20, 30, 40, 50};
   /* reverse iterator points to the last element of the array */
   auto rev_begin = arr.rbegin();   

   /* iterator array in reverse order */
   while (rev_begin < arr.rend()) {
      cout << *rev_begin << " ";
      ++rev_begin;
   }

   cout << endl;

   return 0;
}

Let us compile and run the above program, this will produce the following result −

50 40 30 20 10