Explain different Collection Types.

 Collection Types

• Collection Types are specialized classes for data storage and retrieval.

• These classes provide support for stacks, queues, lists, and hash tables.

• Collection classes serve various purposes, such as allocating memory dynamically to elements and accessing a list of items on the basis of an index, etc.

• Namespaces:

a) System.Collection

b) System.Collection.Generic

a) System.Collection

• ArrayList, Hashtable, Sorted List, Stack, Queue

Exampe of Array List - System.Collections

Arraylist al = new ArrayList();

al.Add(1);

al.Add("Hari"); al.Add(3.4);

Console.WriteLine (al.Count);

al. Remove (3.4);

al. RemoveAt (0);

Console.WriteLine(al. Count);

b)System.Collection.Generic

• generic collection is strongly typed (type-safe), that you can only put one type of object into it.

• This eliminates type mismatches at runtime.

• Another benefit of type safety is that performance is better

Ex: List, Dictionary

Example of List - System.Collection.Generic

List<string> names = new List<string>();

names.Add("Ram");

names.Add("Sam"); Console.WriteLine(names. IndexOf("Ram"));

Console.WriteLine (names.Count);

names.Add("Hari");

names. RemoveAt (2); names. Remove("Ram");

foreach(string n in names)

{ Console.WriteLine(n);

}