Generic Stack and non-generic Stack « Stack « Collections

Stack<T> and Stack are last-in first-out (LIFO) data structures, providing methods to Push and Pop.

 
public class Stack<T> : IEnumerable<T>, ICollection, IEnumerable
{
    public Stack();
    public Stack (IEnumerable<T> collection); // Copies existing elements 
    public Stack (int capacity);  // Lessens auto-resizing 
    public void Clear();
    public bool Contains (T item);
    public void CopyTo (T[] array, int arrayIndex);
    public int Count { get; }
    public Enumerator<T> GetEnumerator(); // To support foreach 
    public T Peek();
    public T Pop();
    public void Push (T item); 
    public T[] ToArray(); 
    public void TrimExcess();
}

 
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;

class Sample
{
    public static void Main()
    {
        var s = new Stack<int>();
        s.Push(1);  //  Stack = 1 
        s.Push(2);  //  Stack = 1,2 
        s.Push(3);  //  Stack = 1,2,3
        Console.WriteLine(s.Count); 
        Console.WriteLine(s.Peek());
        Console.WriteLine(s.Pop()); 
        Console.WriteLine(s.Pop()); 
        Console.WriteLine(s.Pop()); 
        Console.WriteLine (s.Pop());  

    }

}


3
3
3
2
1

Unhandled Exception: System.InvalidOperationException: Stack empty.
   at System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resour
ce)
   at System.Collections.Generic.Stack`1.Pop()
   at Sample.Main() in c:\g\Program.cs:line 19