std::rotate vs std::rotate_copy in C++ STL

// Illustrating the use of rotate algorithm
#include <bits/stdc++.h>
using namespace std;

// Driver Program
int main()
{
    vector<int> arr;

    // set some values: 1 2 3 4 5 6
    // 7 8 9
    for (int i = 1; i < 10; ++i)        
        arr.push_back(i);

    // Use of rotate
    rotate(arr.begin(), arr.begin() + 3, arr.end());

    // prints the content:
    cout << "arr contains:";
    for (auto i = arr.begin(); i != arr.end(); i++)
        cout << ' ' << *i;
    cout << endl;

    return 0;
}

// Illustrating the use of rotate_copy
#include <bits/stdc++.h>
using namespace std;

// Driver Program
int main()
{
    int arr[] = { 10, 20, 30, 40, 50, 60, 70 };    

    // Use of rotate_copy
    vector<int> gfg(7);
    rotate_copy(arr, arr + 3, arr + 7, gfg.begin());

    // prints the content:
    cout << "gfg contains:";
    for (auto i = gfg.begin(); i != gfg.end(); i++)
        cout << ' ' << *i;
    cout << endl;

    return 0;
}