Datastructures in .NET

a.       Stack:

·   FILO (first in last out)

·   Push(object o) – insert an object at top of stack

·   POP() – removes object at top of stack

·   Peek() – returns object at top of stack without removing

·   One of the classic examples of stack in .net framework is in memory management of value types.

·   There are non generic collection stack object (System.Collections.Stack) and generic collection stack object (System.Collections.Generic.Stack)

b.      Queue:

·   FIFO

·   Enqueue(object o) – add an object at end of queue

·   Dequeue() – remove object at beginning of queue

·   Peek() - return object at beginning of queue

·   First object entering to the Queue, exits first

·   One of the classic example of queue implementation in MSMQ

·   Queue is used in the highly reliable communication scenarios. Even if the message channel not available, messages are stored in the queue and transmitted once the channel is up.

·   There are non generic collection object (System.Collections.Queue) and generic collection object (System.Collections.Generic. Queue)

c.       Hashtable           

·   Hashtable stores key – value pair

·   Is organized based on the hash code of the key

·   Each element in hashtable is stored as DictionaryEntry object

·   A key cannot be null, but value can be

·   It is a non generic collection System.Collections type

·   Hashtable stores types of object

·   There is a type conversion required every time when we use hashtable

IDictionary, ICollection, IEnumerable, ISerializable, IDeserializationCallback, ICloneable

d.      Dictionary

·   Dictionary is similar to Hashtable (key-value pair storage)

·   It is a generic collection (System.Collections.Generics)

·   Type of the object to store in the dictionary should specify at compile time

·   Performance wise,  Dictionary is better option that Hashtable

IDictionary, ICollection<KeyValuePair>, IEnumerable<KeyValuePair>, IDictionary, ICollection, IEnumerable, ISerializable, IDeserializationCallback

e.      List

·   It is generics collection (System.Collections. Generics)

·   It represents strongly typed list of objects

·   Consider a scenario to store all the employee names of Satyam, then use List

·   No type conversion required hence preferred over ArrayList

IList, ICollection, IEnumerable, IList, ICollection, IEnumerable

f.        ArrayList

·   ArrayList is a non generic collection (System.Collections)

·   Size can be dynamically increase

·   ArrayList stores objects

·   Type conversion required every time when use AL
·  This affects the performance