Solved

About linked variant record's tagfield in Turbo Pascal 7.0

Posted on 1998-02-14
5
261 Views
Last Modified: 2010-04-16
I got a strange problem in my turbo pascal program
 I declare something like that:

type
  TagField = (term, rowheader, columnheader, polyheader);
  ListPointer = ^ListNode;

  ListNode = record
    NextX : ListPointer;
    NextY : ListPointer;
    case NodeInfo : TagField of
      term:                      
            (Coefficient : integer);
      rowheader:
            (XDegree : integer);
      columnheader:
            (YDegree : integer);
      polyheader:
            (NoOfTerm : integer)
  end;

Then I have a var called
var
  OtherCoeff : ListPointer

and the code like this

   while ((OtherCoeff^.NodeInfo = rowheader) and
               (OtherCoeff^.NodeInfo = polyheader)) do  
                        :
                        :

Somehow this while loop goes into an infinite loop. I check the OtherCoeff
and I am sure it is pointing to the rowheader and not the polyheader
it still doesn't terminate.
it seems that it can't recognize the tagfield

Do you have any idea?
                       
0
Comment
Question by:UTEK
5 Comments
 

Expert Comment

by:bslim
ID: 1217325
Hmm in order to be of use...try to state the rest of the while statement....as something there is to stop the while loop....Hmm...but I'm not used to Turbo Pascal 7 the only Pascal i did was on a Unix computer...
0
 
LVL 2

Accepted Solution

by:
kellyjj earned 20 total points
ID: 1217326
With out seeing the rest of the code,  I can only guess that the problem is in the  variant record.   polyheader and rowheader are actually the same variable, but accessed differently.  I have used variant records to to converstions from integer to hex.  If it is real important that you check both polyheader and rowheader then I would make them seperate items in the record.
0
 

Author Comment

by:UTEK
ID: 1217327
Sorry, I have mis-type the while loop expression in my posting.
My original ctrl statement is:

while ((OtherCoeff^.NodeInfo <> rowheader) and
                  (OtherCoeff^.NodeInfo <> polyheader)) do
:
:

the truth table for that

<> rowheader             <>polyheader           do the loop
     T                         T                     T
     T                         F                     F
     F                         T                     F
     F                         F                     F

Since the loop will never go into the situation of (= rowheader) and (= polyheader), so the last line can be ignored.

0
 
LVL 51

Expert Comment

by:ahoffmann
ID: 1217328
Are you modifying OtherCoeff^.NodeInfo inside the loop?
0
 
LVL 1

Expert Comment

by:santhosh022698
ID: 1217329
Without looking into the code i cannot answer. Try solving
this problem without using variant records, since variant records
are handled in a funnay manner in Pascal.
0

Featured Post

VMware Disaster Recovery and Data Protection

In this expert guide, you’ll learn about the components of a Modern Data Center. You will use cases for the value-added capabilities of Veeam®, including combining backup and replication for VMware disaster recovery and using replication for data center migration.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Include sql text files into resource of Delphi XE project at compile time 3 2,033
using a list of objects, Delphi 3 606
Indy TIdHTTP POSTs getting slow responses 6 1,047
code issue 8 132
Each year, investment in cloud platforms grows more than 20% (https://www.immun.io/hubfs/Immunio_2016/Content/Marketing/Cloud-Security-Report-2016.pdf?submissionGuid=a8d80a00-6fee-4b85-81db-a4e28f681762) as an increasing number of companies begin to…
When you have clients or friends from around the world, it becomes a challenge to arrange a meeting or effectively manage your time. This is where Outlook's capability to show 2 time zones in one calendar comes in handy.
Email security requires an ever evolving service that stays up to date with counter-evolving threats. The Email Laundry perform Research and Development to ensure their email security service evolves faster than cyber criminals. We apply our Threat…

822 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question