Problem while dividing comp-3 variables

bg_anudeep · New User Joined: 17 Aug 2006 Posts: 4

Hi,
I am facing a problem while dividing comp-3 variables.
Below is the description:

variable A PIC S9(12)V9(05)
variable B PIC S9(13)V9(02)
variable C PIC S9(13)V9(05)

now when i am dividing these variables as below

compute C = (B*100)/A
if C > 99
then
...
...
end-if

the value in C is never having a decimal. Should i move the result in C to a numeric-edited variable ?

variable D 9(13).9(05)
MOVE C to D

Bill Woodger · Posted: Fri Jan 06, 2012 4:21 pm

With V the decimal place is always implied. If you need to see a decimal point, yes, you have to use numeric-edited.

If you only think you need to see a decimal point, then leave it as a V. The definition takes care of understanding where the decimal place is With your example, C is calculated to five decimal places. Doesn't matter that you can't "see" a decimal point.

bg_anudeep · New User Joined: 17 Aug 2006 Posts: 4

Hi Bill,

The problem that i am facing is that once i have a value in C , then the further processing is done on the fact if C > 99 %.
now if i put a display on C i always get to see a value without any decimal.

in other words , what i want to achieve is

divide PIC S9(13)V9(02) by PIC S9(12)V9(05)
find out the percentage
and then proceed with the logic if % > 99

so should C be S9(13)V9(05) or some other PIC clause

Thanks

Bill Woodger · Posted: Fri Jan 06, 2012 4:42 pm

Yes, if you do want to be able to see the decimal-point for a value you display, rather than just "know" it is there from the PICture, then MOVE it to a new numeric-edited field which is defined with an explicit decimal-point.

Robert Sample · Posted: Fri Jan 06, 2012 5:17 pm

bg_anudeep, it sounds like you are mixed up about several things:

1. C has an implied decimal point (that's what the V in the PIC means). You will not, under any circumstances, ever see a decimal point if you DISPLAY the value of C. If you want to DISPLAY the value and see a decimal point, you will need to move C to a numeric edited variable.

2. COBOL understands the decimal point, and the IF statement will process the THEN part any time the value of B is at least as large as the value of A. This processing does NOT depend upon any actual decimal point -- COBOL can keep track of implied decimal points quite well.

3. I suspect you're going to have issues with intermediate results since the number of digits after the decimal point varies so much, and especially if the number of digits before the decimal point for the value of B approaches 12.

4. If B and A are close in value (why else use that particular IF statement?), then C does not need 13 digits in front of the decimal place -- 3 or 4 would probably be enough. If B and A can be very different values, then you need to do some numerical analysis and verify that your PIC clauses are big enough to handle all potential problems.

bg_anudeep · New User Joined: 17 Aug 2006 Posts: 4

Hi Robert,

Thanks for the repy.
the problem that i am having is inaccordance with
<3. I suspect you're going to have issues with intermediate results since the number of digits after the decimal point varies so much, and especially if the number of digits before the decimal point for the value of B approaches 12. >

how do you suggest i find out the percentage ?
i had put displays on A B & C got the below result :

B =000000000600360
A =00000002120233333
C =(B*100)/A
C =000000000002831575

Now ideally if i move C to a variable with PIC 9(13).9(05)

what i get is 28.31575 which is incorrect
How should i get the correct percentage

Robert Sample · Posted: Fri Jan 06, 2012 6:59 pm

When I take 6003.60 and multiply by 100 and then divide by 21202.33333, I get 28.315751415459894573782743184521, which is the same number you get to 5 decimal digits.

Since COBOL is getting the correct result, as verified independently, just what do you think the "correct percentage" should be?

enrico-sorichetti · Posted: Fri Jan 06, 2012 7:21 pm

the same with 998 decimal digits

value calculated for A = 21202.33333

bg_anudeep · New User Joined: 17 Aug 2006 Posts: 4

Hi Robert,

Apologies for the mistake i made.
While calculating the percentage i didnt take the decimal into consideration.

Thanks for all your help.

Cheers!!