array::rbegin() and array::rend() in C++ STL

1. array::rbegin() is a built-in function in C++ STL which returns a reverse iterator pointing to the last element in the container. Syntax:

array_name.rbegin()

1. Parameters: The function does not accept any parameter. Return value: The function returns a reverse iterator pointing to the last element in the container. Program to demonstrate the array::rbegin() method: Program 1: 

// CPP program to illustrate 
// the array::rbegin() function 
#include <bits/stdc++.h> 
using namespace std; 

int main() 
{ 
    // array initialisation 
    array<int, 5> arr = { 1, 5, 2, 4, 7 }; 

    // prints the last element 
    cout << "The last element is " << *(arr.rbegin()) << endl; 

    // prints all the elements 
    cout << "The array elements in reverse order are:\n"; 
    for (auto it = arr.rbegin(); it != arr.rend(); it++) 
        cout << *it << " "; 

    return 0; 
} 

The last element is 7
The array elements in reverse order are:
7 4 2 5 1

Time Complexity: O(N) where N is the size of the array.
Auxiliary Space: O(1)

1. array::rend() is a built-in function in C++ STL which returns a reverse iterator pointing to the theoretical element right before the first element in the array container. Syntax:

array_name.rend()

1. Parameters: The function does not take any parameter. Return value: The function returns a reverse iterator pointing to the theoretical element right before the first element in the array container. Program to demonstrate the array::rend() method: Program 1: 

// CPP program to illustrate 
// the array::rend() function 
#include <bits/stdc++.h> 
using namespace std; 

int main() 
{ 
    array<int, 5> arr = { 1, 5, 2, 4, 7 }; 

    // prints all the elements 
    cout << "The array elements in reverse order are:\n"; 
    for (auto it = arr.rbegin(); it != arr.rend(); it++) 
        cout << *it << " "; 
    return 0; 
} 

The array elements in reverse order are:
7 4 2 5 1

Time Complexity: O(N) where N is the size of the array.
Auxiliary Space: O(1)

gopaldave

Follow

Improve

Article Tags :

• Misc
• C++
• STL
• cpp-array
• CPP-Functions

+1 More

Practice Tags :

• CPP
• Misc
• STL