Hi Friends,

I am learning C# and it is sort little confusing since I did some C++ programming. I have couple of questions regarding Collections,Array, ArrayList

1. What are collections? Is it just the namespace with an extensive set of classes or something is more to it?

2. What is ArrayList? How is it different from the Arrays? (In this aspect I am questioning myself with couple of questions and not finding answers so if you could answer them along with any more information, I am highly thankful.)
The basics questions are:
   a. you can declare an array of objects apart from array of value types so why do they need ArrayList
   b. does ArrayList provide some built-in methods that the coder has to codein if he uses array instead of ArrayList
   C. performance issues in case you use ArrayList instead of Array


Thankyou,
CsharpLearner

1. I am not completely sure about the semantics of collections, but AFAIK it was the old term used in VB for a container of objects, through which you can iterate using an enumeration. However, a collection is a broad term now (see link below). You can implement own collections using ICollection.

2. An ArrayList works in the same way as a linked list; or rather you have the same functionality; i.e. the size of the list is dynamic. Using an ordinary array you specify the size first and then use it. Using an ArrayList you can expand the structure later.

Performance-wise I don't know, however, I am pretty sure that ArrayLists are slower since you memory has to be allocated for each expansion of the list. With arrays memory are allocated once and for all when creating the array.

Take a look here. Quite good information on both ArrayList, ICollection etc....
http://msdn.microsoft.com/library/de...croottopic.asp

Hope it helps, Jacob.

Jacob you are awesome....thank you:D