Last element of vector in C++ (Accessing and updating)

In C++ vectors, we can access last element using size of vector using following ways.

1) Using size()

#include <bits/stdc++.h>
using namespace std;

int main()
{
    vector<int> v{10, 20, 30, 40, 50};

    // Accessing last element
    int n = v.size();
    cout << v[n - 1] << endl;

    // modifying last element
    v[n - 1] = 100;

    cout << v[n - 1] << endl;
    return 0;
}

Output :

50
100

2) Using back() We can access and modify last value using back().

#include <bits/stdc++.h>
using namespace std;

int main()
{
    vector<int> v{10, 20, 30, 40, 50};

    // Accessing last element
    cout << v.back() << endl;

    // modifying last element
    v.back() = 100;

    cout << v.back() << endl;
    return 0;
}

Output :

50
100