Stack

// I can't tell you what it really is,
// I can only tell you what it feels like.
#include "bits/stdc++.h"

using namespace std;
class node{
	public:
	int data;
	node *next;
	node() {
		next = NULL;
	}
};
node *top;
void add(int x) {
	if(top -> next == NULL) {
			top -> data = x;
			top -> next = top;
	}	else {
			node *temp = new node;
			temp -> data = x;
			temp -> next = top;
			top = temp;
	}
}
void del() {
		if(top -> next == NULL) {
			cout << "Stack is Empty\n";
		}	else {
			if(top == top -> next) {
				top -> next = NULL;
			}	else {
				node *temp = top;
				top = top -> next;
				delete temp;
			}
		}
}
int on() {
		if(top -> next == NULL)
			return -1;
		else
			return top -> data;
}
int main() {
	int ch, num;
	top = new node;
	while(1) {
		cin >> ch;
		if(ch == 1) {
			cout << "enter num ";
			cin >> num;
			add(num);
		}
		else if(ch == 2){
			del();
		}
		else if(ch == 3)
			cout << on() << '\n';
		else
			break;
	}
}