unordered_multiset empty() function in C++STL

The unordered_multiset::empty() is a built-in function in C++ STL which returns a boolean value. It returns true if the unordered_multiset container is empty. Otherwise, it returns false.

Syntax:

unordered_multiset_name.empty()

Parameters: The function does not accepts any parameter.

Return Value: It returns a boolean value which denotes whether a unordered_multiset is empty or not.

Below programs illustrates the above function:

Program 1:

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

int main()
{

    // declaration
    unordered_multiset<int> sample;

    // inserts element
    sample.insert(11);
    sample.insert(11);
    sample.insert(11);
    sample.insert(12);
    sample.insert(13);
    sample.insert(13);
    sample.insert(14);

    // if not empty then print the elements
    if (sample.empty() == false) {
        cout << "Elements: ";

        for (auto it = sample.begin(); it != sample.end(); it++) {
            cout << *it << " ";
        }
    }

    // container is erased completely
    sample.clear();

    if (sample.empty() == true)
        cout << "\nContainer is empty";
    return 0;
}

Output:

Elements: 14 11 11 11 12 13 13 
Container is empty

Program 2:

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

int main()
{

    // declaration
    unordered_multiset<char> sample;

    // inserts element
    sample.insert('a');
    sample.insert('a');
    sample.insert('b');
    sample.insert('c');
    sample.insert('d');
    sample.insert('d');
    sample.insert('d');

    // if not empty then print the elements
    if (sample.empty() == false) {
        cout << "Elements: ";

        for (auto it = sample.begin(); it != sample.end(); it++) {
            cout << *it << " ";
        }
    }

    // container is erased completely
    sample.clear();

    if (sample.empty() == true)
        cout << "\nContainer is empty";
    return 0;
}

Output:

Elements: a a b c d d d 
Container is empty