IBM MAINFRAME HELP FORUMS for COBOL, JCL, CICS, DB2, IMS etc...

pauly_william · Joined: 15 Oct 2007 Posts: 10 Location: Canada

I'm trying to alter the boundaries of a loop using a compound variable (ie if condition is met move the end of an entry to another line). Hopefully the code illustrates better what I'm trying to accomplish:

Code:
/* rexx */
enum = 1
entry.enum.start = 4
entry.enum.stop = 6

Do i = entry.enum.start to entry.enum.stop
Say "Ln# :"i
If i = 5 Then entry.enum.stop = 10
End i

Output is:

Ln# :4
Ln# :5
Ln# :6

....instead of all the way to Ln# :10

So my question would be, is it possible to alter the loop inside when a condition is met or is the boundaries given will be the boundaries committed to?

expat · Posted: Fri Jun 27, 2008 12:19 pm Post subject:

Maybe a shift in logic, but be warned - This code is untested and is intended purely as a guide :shock:

Code:
/* rexx */
eof = 0
enum = 1
entry.enum.start = 4
entry.enum.stop = 6

i = entry.enum.start

Do until(eof)
Say "Ln# :"i
If i = 5 Then entry.enum.stop = 10
if i = entry.enum.stop
then eof = 1
i = i + 1
End

enrico-sorichetti · Joined: 14 Mar 2007 Posts: 2647 Location: italy

the logic behind is a bit odd, but....
the answer is nooo
the do loop boundaries are computed at do loop initialization
( You can check by running with TRACE "I" )

the only whay ( I tested ) is with a while

Code: start = 4
end = 6
i = start

do while ( i <= end )
say "i " i
if i = 5 then end = 10
i = i + 1
end