unordered_map empty in C++ STL

// CPP program to illustrate
// Implementation of unordered_map empty() function
#include <bits/stdc++.h>
using namespace std;

int main()
{
    // Take any two unordered_map
    unordered_map<int, int> ump1, ump2;

    // Inserting values
    ump1[1] = 2;
    ump1[3] = 4;
    ump1[5] = 6;
    ump1[7] = 8;

    // Print the size of container
    cout << "ump1 size = " << ump1.size() << endl;
    cout << "ump2 size = " << ump2.size() << endl;

    // Running the function for ump1
    if (ump1.empty())
        cout << "True\n";
    else
        cout << "False\n";

    // Running the function for ump2
    if (ump2.empty())
        cout << "True\n";
    else
        cout << "False\n";

    // Running the function for ump1 after
    // clearing it
    ump1.clear();
    if (ump1.empty())
        cout << "True\n";
    else
        cout << "False\n";

    return 0;
}