# ArrayList

Let's talk about the ArrayList class for a moment.

You remember that we said: an array cannot change its size. Right? (immutability)

This is what the ArrayList brings to the table: the ability to dynamically resize arrays.

By resizing I mean to add and remove items as you need without being restricted by a capacity/size.

# How it works?

As elements are added to an ArrayList, the capacity is automatically increased as required through reallocation MSDN

var arrList = new ArrayList();
arrList.Add(12);
arrList.Add("pudding");
arrList.Add(true);

As you can see, we can have items of different types (non-generic collection).

# Practical

But should you use it? Well, nope.

The ArrayList doesn't provide the best performance.

Also, being Non-generic, we have the issue with Boxing and Unboxing (which I will cover soon).

It is recommended to use the List collection for Generics or the List<Object> when you need a heterogeneous collection 😨 (it means a collection which can hold items of different types – like strings, integers, Objects at the same time). 🙂

# Conclusion