ARRAYLIST IN C# (Diff. b/w Array & ArrayList )

ArrayList in c#

            "ArrayList is a class of Collections^{^} ,and it's a data structure that store collection of data just like an array". But it's is little bit different than ArrayList See the detail difference between Array and ArrayList at bottom of this page.  

EXAMPLE OF ARRAYLIST

      1.    How to declare ArrayList in C#

To declare an ArrayList first step to add the directive System. Collection, and what have to do is we have to the instantiate the instance of ArrayList as we did  to the class instance with the help of new keyword see the example

        using System.Collections;

        static void Main()

        {

            ArrayList List = new ArrayList ();

            // the name of ArrayList will be 'List' or you can chose your own name

 }

      2.    How to add item/values into an Arraylist in C#

arraylist in c#

            With the a help of Add keyword we will add object type data in ArrayList

See it

       static void Main()

        {

            ArrayList List = new ArrayList ();

            List.Add(100);

            List.Add("Jhony");

            List.Add('a');

        }

      3.    How to read an ArrayList in C#

Like the old process but little bit change we have to use the Add keyword like this

       static void Main()

        {

            ArrayList List = new ArrayList();

            Console.WriteLine("Enter items into ArrayList");

            List.Add(Console.ReadLine());

        }

       4.    How to write and display the output of an ArrayList in C#

            Because of the ArrayList we will use foreach loop to print the ArrayList

       static void Main()

        {

            ArrayList List = new ArrayList();

            Console.WriteLine("Enter items into ArrayList");

            List.Add(Console.ReadLine());

   

array vs arraylist

            List.Add(100);

            List.Add("Jhony");

            List.Add('a');
            Console.Write("Array items are ");

            foreach (object obj in List)

                Console.Write(" " + obj);

            Console.ReadKey();

        }

      5.    How to insert item/values in the middle of ArrayList

            For this you to specify the index number at the place we want to add the item and by using insert keyword we will insert at any point. Like suppose the above program I want to add 150 in between the "Jhony" and 'a' thus we have to add at index number 3 because index start at zero let do it.

        static void Main()

        {

            ArrayList List = new ArrayList();

            Console.WriteLine("Enter items into ArrayList");

array to arraylist

            List.Add(Console.ReadLine());

            List.Add(100);

            List.Add("Jhony");

            List.Add('a');

            List.Insert(3, 150);

            foreach (object obj in List)

                Console.Write(" " + obj);

            Console.ReadKey();

        }

      6.    How to delete item from middle of ArrayList

            By use of either Remove keyword and specify the 'object obj'. Or RemoveAt keyword by specifying index number. Suppose above program I want to delete "Jhony" we have two ways

First (Remove keyword and specify the 'object obj')       

static void Main()

        {

            ArrayList List = new ArrayList();

            Console.WriteLine("Enter items into ArrayList");

array to arraylist

            List.Add(Console.ReadLine());

            List.Add(100);

            List.Add("Jhony");

            List.Add('a');

            List.Insert(3, 150);

            List.Remove("Jhony");

            foreach (object obj in List)

                Console.Write(" " + obj);

            Console.ReadKey();

        }

Second (RemoveAt keyword by specifying index number)

       static void Main()

        {

            ArrayList List = new ArrayList();

            Console.WriteLine("Enter items into ArrayList");

            List.Add(Console.ReadLine());

            List.Add(100);

            List.Add("Jhony");

            List.Add('a');

            List.Insert(3, 150);

            List.RemoveAt(4);

            foreach (object obj in List)

                Console.Write(" " + obj);

            Console.ReadKey();

        }

Difference between Array and ArrayList in C#

            The difference between Array and Arraylist are listed below

ARRAY	ARRAYLIST
Array is a data structure consisting of collection of data. It’s a normal array.	Arraylist also data structure consisting collection of data, but it’s a c# collection
Arrays have a fixed length, at declaration time we set the length.	Arraylist provide variable length it change its length when we keep adding items.
Once an array defines we cannot resize its size without disturbing the old one. There is no auto resizing property in Array.	The property auto-resizing we can resize the Arraylist once it's formed. Automatically its increase the boxes as needed.
In Array we cannot add or insert any values in middle of the Array. At the specific time it has to insert, not after not before.	In Arraylist we can add or insert any values or item middle of Arraylist at any time when the need arise.
We cannot delete any values from the middle of the Array	Arraylist allow us to delete any item from it's the middle.