Iterators

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

signed main()
{
    vector<int> v = {5 , 6 , 7 , 8};

    cout << *v.begin() << endl; // 5
    cout << *v.end() << endl; //random number
    cout << *(--v.end()) << endl; //8
    cout << *(v.end()--) << endl; // random number
    cout << *(v.begin()++) << endl; // 5
    cout << *(++v.begin()) << endl; // 6
    cout << *(v.begin() + 2) << endl; // number in 2-nd index
    sort(v.begin() , v.end());
    cout << *(lower_bound(v.begin() , v.end() , 7)) << endl; // 7
    cout << *(upper_bound(v.begin() , v.end() , 7)) << endl; // 8
    cout << *(upper_bound(v.begin() , v.end() , 8)) << endl; // random number

    auto it = v.begin();
    cout << *it << endl; // 5
    vector<int>::iterator pt = v.end();
    pt--;
    cout << *pt << endl; // 8
}