task 2( ds lab 4) 3rd sem

#include<iostream>
#include<stack>
using namespace std;
int N;
void showstack(stack <int> s)
{
    while (!s.empty())
    {
        cout << s.top()<<" ";
        s.pop();
    }
    cout << '\n';

}
int main()
{
    cin>>N;
    stack <int> s;
    int t,i;
    cin>>t;
    for(i=0; i<t; i++)
    {
        cout<<"Enter 1 to push and 2 to pop"<<endl;
        int a;
        cin>>a;
        if(a==1)
        {
            cout<<"Enter number"<<endl;
            int b;
            cin>>b;
            s.push(b);
        }
        else
            s.pop();
        cout << "size= " << s.size();
        cout<<" items= ";
        if(!s.empty())
            showstack(s);
        else
            cout<<"NULL"<<endl;

    }
}