#include <list>
#include <vector>
#include <stack>
#include <iostream>
using namespace std;

// Why is this a template?
template<typename T> void print_stack(T q)
{
    while(!q.empty())
    {
        cout << q.top() << " ";
        q.pop();
    }
    cout << endl;
}

int main()
{
    // Constructors
    stack<int> stk1;

    stk1.push(10);
    stk1.push(20);
    stk1.push(30);
    cout << "stk1 = ";
    print_stack(stk1);
    cout << endl;

    list<int> l1{2,3,5,7};
    stack<int, list<int>> stk2(l1);
    cout << "stk2 = ";
    print_stack(stk2);
    cout << endl;

    stk2.emplace(17);
    stk2.emplace(18);
    cout << "stk2 = ";
    print_stack(stk2);
    cout << endl;

    vector<double> v1{1.2,3.4,5.6,7.8};
    stack<double, vector<double>> stk3(move(v1));
    cout << stk3.size() << endl;
    cout << v1.size() << endl;
    cout << "stk3 = ";
    print_stack(stk3);
    cout << endl;

    stack<double> stk4;
    // stk4.swap(stk3);  ERROR - why?

    v1 = {1.3,2.2,3.3};
    stack<double, vector<double>> stk5(v1);
    stk5.swap(stk3);
    cout << "stk3 = ";
    print_stack(stk3);
    cout << "stk5 = ";
    print_stack(stk5);

    stk5.push(3.2);
    cout << "stk5 = ";
    print_stack(stk5);
    cout << "stk3 > stk5: " << boolalpha << (stk3 > stk5) << endl << endl;

    stk3.push(stk3.top());
    stk3.push(stk3.top());
    cout << "stk3 = ";
    print_stack(stk3);
    cout << "stk5 = ";
    print_stack(stk5);
    cout << boolalpha << endl;
    cout << "stk3 > stk5: " << (stk3 > stk5) << endl;
    cout << "stk3 < stk5: " << (stk3 < stk5) << endl;
    cout << "stk3 == stk5: " << (stk3 == stk5) << endl;
}