IBM Mainframe Forum Index
 
Log In
 
IBM Mainframe Forum Index Mainframe: Search IBM Mainframe Forum: FAQ Register
 

Computing statement truncation


IBM Mainframe Forums -> COBOL Programming
Post new topic   Reply to topic
View previous topic :: View next topic  
Author Message
sivasaras

New User


Joined: 29 Sep 2007
Posts: 93
Location: chenna/i-

PostPosted: Tue Jan 06, 2015 9:33 pm
Reply with quote

Hi,

I have a compute statement in my cobol code.

A PIC X(02)

MOVE 32 TO A.

C PIC 9(2)

COMPUTE C = 16 * A

value is 512 but it is storing the value as 12 not 51.

please help me how to store the first 2 numbers.

Thanks
Back to top
View user's profile Send private message
David Robinson

Active User


Joined: 21 Dec 2011
Posts: 199
Location: UK

PostPosted: Tue Jan 06, 2015 9:54 pm
Reply with quote

So you just want the 51 to be stored, ignoring the 2 ???
Back to top
View user's profile Send private message
Robert Sample

Global Moderator


Joined: 06 Jun 2008
Posts: 8696
Location: Dubuque, Iowa, USA

PostPosted: Tue Jan 06, 2015 9:56 pm
Reply with quote

If the PIC clause is too small to hold the result, COBOL aligns to the decimal point (whether explicit or implicit). Your C variable has an implicit decimal point after the second digit, hence the 12 will be stored and the 5 dropped. The easiest way to capture the 51 would be to define C as PIC 9(03) and then REDEFINE a variable on C that is PIC X(02).
Back to top
View user's profile Send private message
Terry Heinze

JCL Moderator


Joined: 14 Jul 2008
Posts: 1249
Location: Richfield, MN, USA

PostPosted: Tue Jan 06, 2015 10:42 pm
Reply with quote

It can be dangerous using a PIC X (alphanumeric) field in a calculation. I'd either redefine it as numeric, or better yet, define A as numeric. Also, read very carefully the section in the Programming Language Manual about the precision of intermediate results when using the COMPUTE statement. COBOL doesn't do what you might expect it to.
Back to top
View user's profile Send private message
Bill Woodger

Moderator Emeritus


Joined: 09 Mar 2011
Posts: 7309
Location: Inside the Matrix

PostPosted: Tue Jan 06, 2015 11:02 pm
Reply with quote

How did you use a PIC X(2) as a source field in a COMPUTE?

Why would you expect 51 to be the answer? I'm not sure I know of any programming language which right-truncates results to fit in a field.

For an answer, you can also truncate your result by dividing by 10. Not normally something I recommend, but since you are multiplying by 16 already, why don't you multiply instead by 1.6?

Terry,

It obviously took me 20 minutes to type that amongst other things. The PIC X definition for A will cause the compiler to upchuck and refuse to even attempt the COMPUTE.

COMPUTE works exactly how it should work. The problem people have with COMPUTE is that they don't read the intermediate results section that you suggested. They tend to think of a computer as a big calculator, or something which uses numbers-of-unlimited-size-and-unlimited-decimal-places-even-though-it-can't-do-decimal-calculations-accurately-in-all-cases.
Back to top
View user's profile Send private message
Rohit Umarjikar

Global Moderator


Joined: 21 Sep 2010
Posts: 3048
Location: NYC,USA

PostPosted: Thu Jan 08, 2015 3:42 am
Reply with quote

Quote:
value is 512 but it is storing the value as 12 not 51


Red Alram--> Is it a bug or a requirement? if bug then simply increase the size of C otherwise use the above methods as suggested.
Back to top
View user's profile Send private message
View previous topic :: :: View next topic  
Post new topic   Reply to topic View Bookmarks
All times are GMT + 6 Hours
Forum Index -> COBOL Programming

 


Similar Topics
Topic Forum Replies
No new posts JOIN STATEMENT PERFORMANCE. DFSORT/ICETOOL 12
No new posts Relate COBOL statements to EGL statement All Other Mainframe Topics 0
No new posts Cobol 4 - The trouble with computing ... COBOL Programming 1
No new posts process statement for SUPREC, CMPCOLM... TSO/ISPF 4
No new posts SYNCSORT/ICETOOL JOINKEYS SORT Statem... DFSORT/ICETOOL 13
Search our Forums:

Back to Top