Thread: ArrayList question.

As far as I know there is no other way to have a dynamic array in C#, unless you do something like

- create normal 1d array of ints
- check wether last value of the array is not null
if so
copy complete array into a bigger array
do some garbage collection
- else
continue adding values

The only major problem with an ArrayList is the boxing of the ints to objects, and when reading and converting to ints from the arraylist the unboxing.

You can easily test performance of an ArrayList vs a normal array by timing the operation like this

start timer for arraylist
create arraylist
store a bunch of ints or whatever in the arraylist
retrieve them again from the arraylist
stop timer for arraylist

now do the same for a normal array and see the difference, most of the time needed to add / retrieve values from an ArrayList goes into the boxing/unboxing...

edit: a quick solution to your problem is to do something like

Code:

int []ar;
string input = Console.ReadLine();
....
//go over string and check how many ints there are -> store result in "numberOfInts"
ar = new int[numberOfInts];
//go again over the whole string and add ints to the array

But as you can see ... its somehow messy...

If you're using the 2.0 framework, you can use a generic List instead of the ArrayList. The generic List doesn't suffer the same performance penalties as the ArrayList with boxing/unboxing. Further, all access of the generic List is strongly typed, not object references that you have to cast every time.