using System;
using System.Collections.Generic;

public class StackExample
{
    public static void Main(string[] args)
    {
        Stack names = new Stack();
        names.Push("Sonoo");
        names.Push("Peter");
        names.Push("James");
        names.Push("Ratan");
        names.Push("Irfan");

        foreach (string name in names)
        {
            Console.WriteLine(name);
        }

        Console.WriteLine("Peek element: "+names.Peek());
        Console.WriteLine("Pop: "+ names.Pop());
        Console.WriteLine("After Pop, Peek element: " + names.Peek());

    }
}

Sonoo
Peter
James
Ratan
Irfan
Peek element: Irfan
Pop: Irfan
After Pop, Peek element: Ratan