set::rbegin() and set::rend() in C++ STL (original) (raw)

Last Updated : 19 Jun, 2018

1. set::rbegin() is a built-in function in C++ STL which returns a reverse iterator pointing to the last element in the container. Syntax:
   reverse_iterator set_name.rbegin()
   Parameters: The function does not take any parameter.Return value: The function returns a reverse iterator pointing to the last element in the container. Program to demonstrate the set::rbegin() method:Program 1: CPP `
   // CPP program to demonstrate the
   // set::rbegin() function

#include <bits/stdc++.h>
using namespace std;
int main()
{
int arr[] = { 14, 12, 15, 11, 10 };
// initializes the set from an array
set s(arr, arr + 5);
set::reverse_iterator rit;
// prints all elements in reverse order
for (rit = s.rbegin(); rit != s.rend(); rit++)
cout << *rit << " ";
cout << "\nThe last element in set is " << *(s.rbegin());
return 0;
}
`
Output:
15 14 12 11 10
The last element in set is 15

1. set::rend() in an inbuilt function in C++ STL which returns a reverse iterator pointing to the theoretical element right before the first element in the set container. Syntax:
   reverse_iterator set_name.rend()
   Parameter: The function does not accepts any parameter.Return value: The function returns a reverse iterator pointing to the theoretical element right before the first element in the set container. Below programs illustrate the function:Program 1: CPP `
   // CPP program to demonstrate the
   // set::rend() function

#include <bits/stdc++.h>
using namespace std;
int main()
{
int arr[] = { 4, 3, 5, 1, 2 };
// initializes the set from an array
set s(arr, arr + 5);
set::reverse_iterator rit;
// prints all elements in reverse order
for (rit = s.rbegin(); rit != s.rend(); rit++)
cout << *rit << " ";
return 0;
}
`