list rbegin() and rend() function in C++ STL

1. list::rbegin() is an inbuilt function in C++ STL that returns a reverse iterator which points to the last element of the list. Syntax:

list_name.rbegin()

1. Parameter: This function does not accept any parameters. Return value: It returns a reverse iterator which points to the last element of the list. Below program illustrates the above function: 

CPP

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

int main()
{
 list<int> lis = { 10, 20, 30, 40, 50 };

 cout << "The list in reverse order: ";

 for (auto it = lis.rbegin(); it != lis.rend(); ++it)
  cout << *it << " ";

 return 0;
}

Output:

The list in reverse order: 50 40 30 20 10

Time Complexity: O(n)

Auxiliary Space: O(1)

1. list::rend() is an inbuilt function in C++ STL that returns a reverse iterator which points to the position before the beginning of the list. Syntax:

list_name.rend()

1. Parameter: The function does not accept any parameters. Return value: It returns a reverse iterator which points to the position before the beginning of the list. Below program illustrates the above function: 

CPP

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

int main()
{
 list<int> lis = { 10, 20, 30, 40, 50 };

 cout << "The list in reverse order: ";

 for (auto it = lis.rbegin(); it != lis.rend(); ++it)
  cout << *it << " ";

 return 0;
}

Output:

The list in reverse order: 50 40 30 20 10

Time Complexity: O(n)

Auxiliary Space: O(1)