How to sum the first non-missing values rows in SAS

[tSAS1]

I have the dataset below:

ID	a	b	c	d
1	1	1	.	.
2	1	.	1	1
3	1	1	1	.

and I want to add another column called "Result", that sum the variables a,b,c and d without taking into account the missing values and values after the missings.

The data I want to get is like this one:

ID	a	b	c	d	Result
1	1	1	.	.	2
2	1	.	1	1	1
3	1	1	1	.	3

Ps: in my real data I have more than 4 variables (a,b,c,d)

How could I program it in SAS and thanks in advance.

[Kurt_Bremser · Accepted solution]

data have;
infile datalines dlm="09"x;
input ID a b c d;
datalines;
1	1	1	.	.
2	1	.	1	1
3	1	1	1	.
;

data want;
set have;
array x {*} a--d;
do result = 1 to dim(x) until (x{result} = .);
end;
result = result - 1;
run;

[ballardw]

One clarification, what if A, or your "first" variable, has a missing value? Is that to be an exception to not adding anything else?