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

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

reverse_iterator multiset_name.rbegin()

1. Parameters: The function does not take any parameter. Return value: The function returns a reverse iterator pointing to the last element in the container. Below program illustrate the multiset::rbegin() method: 

CPP

// CPP program to demonstrate the
// multiset::rbegin() function
#include <bits/stdc++.h>
using namespace std;
int main()
{

    int arr[] = { 15, 12, 15, 11, 10, 10 };

    // initializes the set from an array
    multiset<int> s(arr, arr + 6);

    multiset<int>::reverse_iterator rit;

    // prints all elements in reverse order
    for (rit = s.rbegin(); rit != s.rend(); rit++)
        cout << *rit << " ";

    cout << "\nThe last element in multiset is " << *(s.rbegin());

    return 0;
}

Output:

15 15 12 11 10 10 
The last element in multiset is 15

1. multiset::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 multiset container. Syntax:

reverse_iterator multiset_name.rend()

1. 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 multiset container. Below program illustrate the multiset::rend() function: 

CPP

// CPP program to demonstrate the
// multiset::rend() function
#include <bits/stdc++.h>
using namespace std;
int main()
{

    int arr[] = { 15, 13, 15, 11, 13, 10 };

    // initializes the set from an array
    multiset<int> s(arr, arr + 6);

    multiset<int>::reverse_iterator rit;

    // prints all elements in reverse order
    for (rit = s.rbegin(); rit != s.rend(); rit++)
        cout << *rit << " ";

    return 0;
}

Output:

15 15 13 13 11 10

Let us see the differences in a tabular form -:

	multiset rbegin()	multiset rend()
1.	It is used to return a reverse iterator pointing to the last element in the container	It is used to return a reverse iterator pointing to the theoretical element right before the first element in the multiset container
2.	Its syntax is -: reverse_iterator rbegin();	Its syntax is -: reverse_iterator rend();
3.	It does not take any parameters.	It does not take any parameters.
4.	Its complexity is constant.	Its complexity does not changes.
5.	Its iterator validity does not changes.	Its iterator validity does not change.