// Implement stack, push(), pop(), empty?(), full?()
#include<iostream>
using namespace std;

class Stack
{
    int a[50], top;

    public:
    Stack() { top = 0; }

    void push(int x)
    {
        if (top >= 50)
            return;
        a[top] = x;
        top++;
    }

    int pop()
    {
        if (top <= 0)
            return -1;
        int x = a[top - 1];
        top--;
        return x;
    }

    bool empty() { return top == 0; }

    bool full() { return top != 0; }
};

int main()
{
    Stack s;
    int x, item, choice;
    while(true)
    {
        cout << "\n1. Push\n2. Pop\n3. Check if empty\n4. Check if full\n5. Quit\nSelect an option: ";
        cin >> choice;
        switch(choice)
        {
            case 1: 
                cout << "Enter number of elements to enter: ";
                cin >> x;
                cout << "Enter " << x << " items for stack:\n";
                for(int i = 0; i < x; i++)
                {
                    cin >> item;
                    s.push(item);
                }
                break;
            case 2:
                cout << "Enter number of elements to pop: ";
                cin >> x;
                for(int i = 0; i < x; i++)
                {
                    cout << s.pop() << "\n";
                }
                cout << x << " items popped from the stack.\n";
                break;
            case 3:
                if(s.empty())
                    cout << "Stack is empty.\n";
                else
                    cout << "Stack is not empty.\n";
                break;
            case 4:
                if(s.full())
                    cout << "Stack is full.\n";
                else
                    cout << "Stack is not full.\n";
                break;
            case 5:
                cout << "Bye!\n";
                return 0;
        }
        cout << "\n";
    }
    return 0;
}