Incrementing by one for every record

[lsehlola]

Hi

I am trying to to increment the product field by 1 for each occurrence of account number. i.e account number 1 has three records where the product 1 and 2 are populated.  want to look at the last value for the the product number and add one to it.

please see example below:

Account	Product
1	1
1	2
1
2	1
2	2
2	3
2
3	1
3	2
3	3
3	4
3
3
3

  expected outcome:

Account	Product
1	1
1	2
1	3
2	1
2	2
2	3
2	4
3	1
3	2
3	3
3	4
3	5
3	6
3	7

[PeterClemmensen]

Try this

data have;
infile datalines missover;
input Account Product;
datalines;
1 1
1 2
1  
2 1
2 2
2 3
2  
3 1
3 2
3 3
3 4
3  
3  
3  
;

data want(drop = p);
   set have;
   if Product then p = Product;
   else do;
      p = sum(p, 1);
      Product = p;
   end;
   retain p;
run;