include <bits/stdc++.h>

using namespace std;

template <typename T>
struct my_vector{
    int length;
    int tail;
    T* data;
    my_vector() {
        length = 10;
        tail = 0;
        data = (T*) malloc(length * sizeof(T));
    }
    void expand() {
        if (tail == length) {
            length += length;
            data = (T*) realloc(data, length * sizeof(T));
        }
    }

    void push(T x) {
        data[tail] = x;
        tail++;
        expand();
    }

    T pop() {
        tail--;
        return data[tail];
    }
};


int main() {
    my_vector<int> a;
    a.push(1);
    a.push(4);
    cout << a.pop() << endl;
    cout << a.pop() << endl;

    my_vector<double> b;
    b.push(3.5);
    b.push(6.6);
    cout << b.pop() << endl;
    cout << b.pop() << endl;

    my_vector<string> c;
    c.push("aaa");
    c.push("bbb");
    cout << c.pop() << endl;
    cout << c.pop() << endl;
}