Placement and creation of a dynamin array

Question

I have a report that returns between 100-200 records.
Sorted by @name+date
It is only 3 data columns.
Name -  allocated -  date
What i want to do is create a 4th column which is the
calculated by "current allocated" - "previous allocated"
i have this working with a formula that uses PREVIOUS/NEXT
However i am unable to total/summary this formula or even
see it(see Summarize a formula which has Next/Previous)
so what i want to do is create a dynamic array for each column.
Name - allocated - date
How or where do i place the formula that holds the array data ?
thanks

Answer 1

Hi John,
I'm not sure why the gtotal gets zeroed on each page; it should not. Is this column in the details section?
Here's something you could try with arrays as well:
1) Create this formula and place it in the section which holds the 4th column:
whileprintingrecords;
numbervar array arr;
numbervar i := recordnumber;
redim preserve arr<i>;
arr<i> := {Curr_Prev};
2) Create another formula and place this on the report footer:
whileprintingrecords;
numbervar array arr;
numbervar result;
numbervar j;
for j := 1 to ubound(arr) step 1 do
   result := result + arr[j]
result;
Hope this helps!
-Abhilash