C++ Standard Library C++ STL Library

C++ <array> - rbegin() Function



The C++ array::rbegin function returns the reverse iterator pointing to the last element of the array. A reverse iterator iterates in backward direction and increasing it results into moving to the beginning of the array container. Similarly, decreasing a reverse iterator results into moving to the end of the array container. Please note that, Unlike the array::back function, which returns a direct reference to the last element, it returns the reverse iterator pointing to the same element of the array.

C++ rbegin rend

Syntax

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

Parameters

No parameter is required.

Return Value

A reverse iterator to the reverse beginning of the sequence container. If the sequence object is constant qualified, the function returns a const_reverse_iterator, else returns an reverse_iterator.

Time Complexity

Constant i.e, Θ(1)

Example:

In the example below, the array::rbegin function returns the reverse iterator pointing to the last element of the array MyArray.

#include <iostream>
#include <array>
using namespace std;
 
int main (){
  array<string, 3> MyArray{"Alpha","Coding","Skills"};
  array<string, 3>::reverse_iterator rit;

  rit = MyArray.rbegin();
  cout<<*rit<<" ";
  rit++;
  cout<<*rit<<" ";
  rit++;
  cout<<*rit<<" ";
  return 0;
}

The output of the above code will be:

Skills Coding Alpha 

Example:

Lets see another example where the array called MyArray contains integer values and array::rbegin function is used with array::rend function to specify a range including all elements of the array container.

#include <iostream>
#include <array>
using namespace std;
 
int main (){
  array<int, 5> MyArray{10, 20, 30, 40, 50};
  array<int, 5>::reverse_iterator rit;

  for(rit = MyArray.rbegin(); rit != MyArray.rend(); ++rit)
    cout<<*rit<<" ";
    
  return 0;
}

The output of the above code will be:

50 40 30 20 10 

❮ C++ <array> Library

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