C++ <array> - back() Function

The C++ array::back function returns a reference to the last element of the array. Please note that, Unlike the array::rbegin function, which returns the reverse iterator pointing to the last element, it returns the a direct reference to the same element of the array.

Syntax

• C++11

reference back();
const_reference back() const;

Parameters

No parameter is required.

Return Value

A reference to the last element of the array.

Time Complexity

Constant i.e, Θ(1).

Example:

In the example below, the array::back function is used to access the last element of the array Arr.

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

  cout<<"The last element of Arr is: ";
  cout<<Arr.back();

  //Adding 100 to the last element of the Arr
  Arr.back() = Arr.back() + 100;

  cout<<"\nThe last element of Arr is: ";
  cout<<Arr.back();  
  return 0;
}

The output of the above code will be:

The last element of Arr is: 50
The last element of Arr is: 150