#include <iostream>
#include <iomanip>
#include <vector>
#include <string>

using namespace std;

struct MyDataT{
    int a;
    string b;
};

void Scenario1();
void Scenario2();

int main() {
    Scenario1();
    Scenario2();

    return 0;
}

void Scenario1() {
    vector<int> data {1,2,3,4,5,6,7,8,9};

    vector<int>::iterator i;
    vector<int>::const_iterator j;
    vector<int>::reverse_iterator k;
    vector<int>::const_reverse_iterator l;

    for(i = data.begin(); i != data.end(); ++i) {
       cout << setw(5) << *i;
       *i *= 4;
    }
    cout << endl << endl;

    for(j = data.cbegin(); j != data.cend(); ++j) {
        cout << setw(5) << *j;
        // *j = 8;
    }

    cout << endl << endl;

    for(k = data.rbegin(); k != data.rend(); ++k) {
       cout << setw(5) << *k;
       *k /= 4;
    }

    cout << endl << endl;

    for(l = data.crbegin(); l != data.crend(); ++l) {
       cout << setw(5) << *l;
       //*l = 4;
    }

    cout << endl << endl;
}

void Scenario2() {
    vector<MyDataT> data{{1,"hello"},{2,"World"}};
    vector<MyDataT>::iterator i;

    for(i = begin(data); i != end(data) ; ++i) {
       cout << "\t" << i - data.begin() << " is "   << i->a << ": " << i->b << endl;
    }
    cout << endl;
    
}