with ArrayList,you do not need to specify the size, for example;ArrayList array = new ArrayList();for (int i=0; i < 10; i++) { ArrayList array2 = new ArrayList(); for (int j=0; j < 20; j++) array2.Add(j); array.Add(array2); }then you can do ((ArrayList)array[i])[j]
{
ArrayList array2 = new ArrayList();
for (int j=0; j < 20; j++)
array2.Add(j); array.Add(array2);
}then you can do
((ArrayList)array[i])[j]