using System;

using System.Collections;

​

public class Program

{

    public static void Main()

    {

        ArrayList arlist=new ArrayList();

        arlist.Add(Console.ReadLine());

        //or

        var arrlist=new ArrayList(){ 1, "second", 1.4f};

        foreach(var a in arrlist){

            Console.WriteLine(a+" ");

        }

        //AddRange(ICollection c) method to add an entire Array, HashTable, SortedList, ArrayList, BitArray, Queue, and Stack

        arrlist.AddRange(arlist);

        foreach(var a in arrlist){

            Console.WriteLine(a+" ");

        }

        //ArrayList

        /*

        arlist.Count

        arlist1.InsertRange(2, arlist2);

        arlist.Insert(1, "Second Item");

        Console.WriteLine(arList.Contains(300)); // true

        arList.Remove(null); //Removes first occurance of null

arList.RemoveAt(4); //Removes element at index 4

arList.RemoveRange(0, 2);//Removes two elements starting from 1st item (0 index)*/

        //Stack

        /*

        Stack<int> myStack = new Stack<int>();

myStack.Push(1);

int[] arr = new int[]{ 1, 2, 3, 4};

Stack<int> myStack = new Stack<int>(arr);

while (myStack.Count > 0)

     Console.Write(myStack.Pop() + ",");

     Console.WriteLine(myStack.Peek()); // prints 4

     myStack.Contains(2); // returns true

        */

        //Queue

        /*

        Queue<int> callerIds = new Queue<int>();

callerIds.Enqueue(1);

callerIds.Enqueue(2);

while (strQ.Count > 0)

    Console.WriteLine(strQ.Dequeue()); //prints Hello

    Console.WriteLine(strQ.Peek()); //prints H

    callerIds.Contains(2); //true

        */

        //Dictionary

        /*

        Implements IDictionary<TKey, TValue> interface.

        Elements are stored as KeyValuePair<TKey, TValue> objects.

        IDictionary<int, string> numberNames = new Dictionary<int, string>();

numberNames.Add(1,"One"); //adding a key/value using the Add() method

var cities = new Dictionary<string, string>(){

    {"UK", "London, Manchester, Birmingham"},

    {"USA", "Chicago, New York, Washington"},

    {"India", "Mumbai, New Delhi, Pune"}

};

foreach(var kvp in cities)

    Console.WriteLine("Key: {0}, Value: {1}", kvp.Key, kvp.Value);

    Console.WriteLine(cities["UK"]); //prints value of UK key

    if(cities.ContainsKey("France")){  

    Console.WriteLine(cities["France"]);

}

//use ElementAt() to retrieve key-value pair using index

for (int i = 0; i < cities.Count; i++)

{

    Console.WriteLine("Key: {0}, Value: {1}", 

                                            cities.ElementAt(i).Key, 

                                            cities.ElementAt(i).Value);

}

cities["USA"] = "Los Angeles, Boston"; // update value of USA key

if(cities.ContainsKey("France")){ // check key before removing it

    cities.Remove("France");

}

        */

    }

}