#include <iostream>

using namespace std;

struct Person
{
    string name;
    string room;
};

class myvector
{
    private:
    int vsize;
    int maxsize;
    Person* array;
    void alloc_new();
    public:
    myvector();
    myvector(Person);
    myvector(const myvector&); //copy constructor
    ~myvector();
    void push_back(Person);
    int size();
    int operator [] (Person);
    int at(int i);

};

myvector::myvector()
{
    maxsize = 20;
    array = new Person[maxsize];
    vsize = 0;
}
myvector::myvector(int i)
{
    maxsize = i;
    array = new Person[maxsize];
    vsize = 0;
}

myvector::myvector(const myvector& v)
{
    maxsize = v.maxsize;
    vsize = v.vsize;
    array = new Person(maxsize);
    for(int i = 0; i < v.vsize ; i++)
    {
        array[i] = v.array[i];
    }
}

myvector::~myvector()
{
    delete[] array;
}

void myvector::push_back(Person i)
{
    if(vsize + 1 > maxsize)
    {
        alloc_new();
    }
    array[vsize] = i;
    vsize++;
}

int myvector::operator[] (int i)
{
    return array[i];
}

int myvector::at(int i)
{
    if(i < vsize)
    {
        return array[i];
    }
}

int myvector::size()
{
    return vsize;
}

void myvector::alloc_new()
{
    maxsize = vsize*2;
    Person *tmp = new Person[maxsize];
    for(int i = 0; i < vsize; i++)
    {
        tmp[i] = array[i];
    }
    delete[] array;
    array = tmp;
}


int main()
{
    string name;
    string room;
    myvector vec;
    Person tmp;
    while(1)
    {
        cin >> tmp;
        //if (tmp == -1)
        {
           break;
        }
        vec.push_back(tmp);
    }
    cout << "you have entered" << vec.size() << "elements. These are: \n";
    for(int i = 0; i < vec.size(); i++)
    {
        //cout << vec[i] << " ";
    }
    cout << "\n";
    return 0;
}