what is the purpose of indexer?

Hi,
Indexers let you get a reference to an object in a collection without having to traverse the whole collections.

Say you have several thousands of objects, and you need the one before last. Instead of iterating over all of the items in the collection, you simply use the index of the object you want.

Indexers do no have to be integers, so you can use a string, for example, (though you can use any object, so long as the collection supports it) as an indexer - this lets you "name" objects in a collection for later retrieval, also quite useful.

Regards,
Iftikar