using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        //Array

        char[] extraGrade = { 'A', 'B', 'C' };

        Stack<char> grades = new Stack<char>(extraGrade);

        Console.WriteLine("---------Push() : To add items---------");

        grades.Push('D');

        grades.Push('E');

        foreach (char grade in grades) //iterate through all the items

            Console.WriteLine(grade);

        Console.WriteLine("\n---------Peek() : To get highest item without removing it---------");

        Console.WriteLine(grades.Peek()); // Prints E            

        Console.WriteLine("\n---------Contains() : Check and return Boolean if B exists in the collection---------");

        Console.WriteLine(grades.Contains('B')); // Prints True

        Console.WriteLine("\n---------Count : To get total items---------");

        Console.WriteLine(grades.Count); // Prints 5

        Console.WriteLine("\n---------Pop() : To remove highest item---------");

        Console.WriteLine(grades.Pop()); // Prints E

        Console.WriteLine($"\nTotal items in collection : {grades.Count}"); // Removed 1 item due to POP method. Total items 4

        Console.WriteLine("\n---------Return removed items from stack using While loop---------");

        Console.WriteLine($"\nTotal items in collection before Pop() in while loop : {grades.Count}\n");

        while (grades.Count > 0)

            Console.WriteLine(grades.Pop()); // While loop with POP removed all items 1 by 1

        Console.WriteLine($"\nTotal items in collection after Pop() in while loop: {grades.Count}");

​

        //Refill items

        grades = new Stack<char>(extraGrade);

        Console.WriteLine("\n---------Clear() : Remove all the items---------");

        Console.WriteLine($"\nTotal items in collection before Clear() : {grades.Count}");

        grades.Clear();

        Console.WriteLine($"\nTotal items in collection after Clear() : {grades.Count}");

    }

}