dynamic array of records in dynamic array of records!!

Hey all,

I have a couple of records as follows :

type
 WEAPON = record
  size : byte;
  posX : double;
  posY : double;
  posZ : double;
  rotX : double;
  rotY : double;
  rotZ : double;
end;

type
 DATA = record
  LowestX : double;
  LowestY : double;
  HighestX : double;
  HighestY : double;
  weight : double;
  braking : double;
  power : double;
  hitpoints : integer;
  cost : integer;
  name : string;
  path : string;
  WeaponsNumber : byte;
  Weapons : array of WEAPON; //<---- right here!
end;

As u see, the DATA record has an array of WEAPON at the bottom.... ( as shown)

now i have a global dynamic array of DATA which works fine,

  Tanks : array of DATA;

and i can call stuff like

SetLength(Tanks, 100);
Tanks[0].weight = 1000;

but when i call SetLength on the WEAPONS record within the DATA one, an access violation occurs...
i.e.
SetLength(Tanks[0].Weapons, 100); //Access violation!!!

Please help!!!

Regards,
-Rob-
Excalibur81Asked:
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

x
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

jcondeCommented:
I tested the following code out and worked fine:

procedure TForm1.Button1Click(Sender: TObject);
var
Tanks : array of DATA;
begin
  SetLength(Tanks, 100);
  Tanks[0].weight := 1000;
  SetLength(Tanks[0].Weapons, 100);
  tanks[0].Weapons[0].size := 9;
  showmessage(inttostr(tanks[0].Weapons[0].size));
  tanks[0].Weapons[2].size := 54;
  showmessage(inttostr(tanks[0].Weapons[2].size));
end;

WinXP Pro / D7 Ent
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
jcondeCommented:
BTW, even though it would slightly add complexity to your code, I would suggest you use a TList for this instead of a dynamic array.
0
geobulCommented:
Hi,

No access violation occurs in my Delphi 5. Everything is just fine:

var
  Form1: TForm1;
  Tanks : array of DATA;

implementation

{$R *.DFM}

procedure TForm1.Button1Click(Sender: TObject);
begin
  SetLength(Tanks, 100);
  Tanks[0].weight := 1000;
  SetLength(Tanks[0].Weapons, 100);
  Tanks[0].Weapons[0].PosX := 100.25;
  ShowMessage(FloatToStr(Tanks[0].Weapons[0].PosX));
end;

Regards, Geo
0
Python 3 Fundamentals

This course will teach participants about installing and configuring Python, syntax, importing, statements, types, strings, booleans, files, lists, tuples, comprehensions, functions, and classes.

ZhaawZSoftware DeveloperCommented:
btw, you could use length(tanks[n].weapons) instead of tanks[n].weaponnumber ;)
0
Excalibur81Author Commented:
Ahhh i see now, it was a logic mistake :)

Hmm, so since there was actually no problem, how do points work??


Also.....

"BTW, even though it would slightly add complexity to your code, I would suggest you use a TList for this instead of a dynamic array. "
Unfortunatly, im saving the data in a file which will be read later on by a program in C++, and needs to be in this fairly specific format.... thanks anyways :)

"btw, you could use length(tanks[n].weapons) instead of tanks[n].weaponnumber ;) "
Yes i had seen that, but for now im just using this for debugging purposes, but thanks also :)

0
jcondeCommented:
I beleive you should split the points between geobul and myself.  geobul, what do you suggest ?
0
geobulCommented:
jconde should get the points. I just confirmed that for D5.
0
Excalibur81Author Commented:
Thanks guys :)

Soz, i meant to split the points, but ive never done before, and i thought it was inside the "Accept Answer" path....

but i guess geobul didnt want them anyways :D


Thanks!!!
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Delphi

From novice to tech pro — start learning today.