#include<iostream>
#include<climits>
#include<stack>
using namespace std;
class Stacks{
    int *data;
    int nextIndex;
    int capacity;
    public:
    Stacks()
    {
        data=new int[4];
        nextIndex=0;
        capacity=4;
    }
    int size()
    {
        return nextIndex;
    }
    bool isEmpty()
    {
        return nextIndex==0;
    }
    void push(int element)
    {
        if(nextIndex==capacity){
        int *newData=new int[2*capacity];
        for(int i=0;i<capacity;i++){
            newData[i]=data[i];
        }
            capacity *=2;
            delete [] data;
            data=newData;
        }
     data[nextIndex]=element;
      nextIndex++;

    }
    int pop()
    {
        if(isEmpty())
        {
            cout<<"Stack is empty"<<endl;
            return INT_MIN;
        }
        nextIndex--;
        return data[nextIndex];
    }
    int top()
    {
        if(isEmpty())
        {
            cout<<"Stack is empty"<<endl;
            return INT_MIN;
        }
        return data[nextIndex-1];
    }
};
int main()
{
    Stacks s;
    s.push(10);
    s.push(20);
    s.push(30);
    s.push(40);
    s.push(50);

    cout<<s.top()<<endl;
    cout<<s.pop()<<endl;
    cout<<s.pop()<<endl;
    cout<<s.pop()<<endl;
    cout<<s.size()<<endl;
    cout<<s.isEmpty()<<endl;
}