Mysterious problems with a linear search.

[benwrcoder]

Code: Pascal  [Select][+][-]

1. function findPID_real(target:integer):integer;
2. var
3.   x,idgotten:integer;
4. begin
5.   findPID_real:=-1;
6.   for x:= 0 to mainlist.count-1 do
7.   begin
8.      idgotten:=mainList[x].GetID;
9.      showmessage('target='+IntToStr(target));
10.      showmessage('GetID '+IntToStr(x)+'= '+IntToStr(mainlist[x].GetID));
11.      if ( idgotten = target) then
12.         findPID_real:=target
13.  
14.  
15.   end;
16. end;    

The showmessages say that the ID is anywhere from 100,000 to 600,000, when the only entries are 1,2,3,4,5,6,7,9

Has anyone ever encountered somethin similar?

[howardpc]

Of course. Every programmer writes buggy and mistake-ridden code (inadvertently, of course).
Perhaps the first place to look for the problem is the GetID routine.

[benwrcoder]

Thanks for the quick reply, but getID is a simple one-line getter

Code: Pascal  [Select][+][-]

1. Function Poultryobj.GetID():integer;
2. begin
3.          GetID:=ID;
4. end;          

[FTurtle]

I think it is a good idea to write a little compilable example and place it here.

[Martin_fr]

Code: Pascal  [Select][+][-]

1. function findPID_real(target:integer):integer;
2.   for x:= 0 to mainlist.count-1 do
3. ...
4.      if ( idgotten = target) then
5.         findPID_real:=target
6. end;    

I dont know if it is related to your issue, but the last line probably is meant to be

Code: Pascal  [Select][+][-]

1.      if ( idgotten = target) then
2.         findPID_real:= x;
3.  

Currently you return "target" (the value of the PID, not it's index), that makes no sense as you already know it (you passed it in).

[benwrcoder]

I realised that it was passing the wrong number, thanks, but the bug is still there.

I can't really upload a "small executable" because A) This is the only place in the entire program where the bug occurs, and B) This is part of a piece of coursework and I'd really like it to not be on the web in entirety.

More info:

mainlist[whatever].GetID is used in other places and returns the real values just fine there. However, I have an identical procedure using a different list, and it experiences the same problem

It's not a bug with the IntToStr , since

Code: Pascal  [Select][+][-]

1.      if( mainlist[x].getID>1000)then
2.          showmessage('Very bad!');    

triggers the condition,

when IntToStr(x) is returned, x is exactly what it should be

and it's not to do with the For loop, since the same issue occurs after changing it to a Repeat Until loop

Index	mainlist[index].getID
0	1
1	2
2	3
3	4
4	5
5	6
6	7
7	8
8	9
9	11
10	12

[FTurtle]

Show how you fill mainlist

[eny]

This might do the trick.
Now on discount.

[Nitorami]

benwrcoder

You are stealing people's time by your secretiveness about the code, and you seem to insinuate there is a bug in the compiler others have encountered before. Of course this cannot entirely be excluded but the problem is much more likely on your side. If you want help, you really should provide a small working program which demonstrates the problem.

Other than that, we can only guess, and the only advice I have is to compile the program will range check etc. set to ON, to check whether you have a range overflow somewhere.

[Leledumbo]

Put a watch on the respective variable then run your program step by step. I can't debug what I can't see and examine.

[benwrcoder]

I tried to upload the code but the forum complained it exceeded the 20,000 character limit

[Nitorami]

Well, what a luck, because who would want to read through that ?
It would be most useful of you try to strip the problem down, by removing unnecessary procedures one by one until a comprehensive rest remains which still shows the problem. Not > 20.000 characters please.

[shobits1]

That why the forum support compressed files.
also you can link to external site like http://pastebin.com/.

[Leledumbo]

That why the forum support compressed files.
also you can link to external site like http://pastebin.com/.

Well even if he provides the full source, I wouldn't want to check that >20k chars code. He must be able to trim down the program while maintaining the problem he describes.

[eny]

He must be able to trim down the program while maintaining the problem he describes.

And while doing that he might even find the problem himself