dyn. array as parameter of a procedure

I need a procedure to fill a dyn. array. How to do that? The following example cause an error at "SetLength(v, 10);". Can you correct the example?

procedure FillArray(var v:array of integer);
begin
  SetLength(v, 10);
  v[5]:=12;
end;

procedure TForm1.Button1Click(Sender: TObject);
var v:array of integer;
begin
  FillArray(v);
  if v[5]=12 then beep;
end;
bengoreAsked:
Who is Participating?
 
MadshiConnect With a Mentor Commented:
When you declare a function like...

procedure FillArray(var v: array of xxx);

... you can't change the length of the array, because you can also call "FillArray" with a static array parameter. How shall FillArray know whether the parameter is a static or a dynamic one?

You have to declare a dynamic array type like this:

type TDAInteger = array of integer;

procedure FillArray(var v: TDAInteger);
begin
  SetLength(v, 10);
  v[5] := 12;
end;

procedure TForm1.Button1Click(Sender: TObject);
var v : TDAInteger;
begin
  FillArray(v);
  if v[5] = 12 then beep;
end;

Regards, Madshi.
0
 
MotazCommented:
You must allocate space befor pass it to your fill procedure:

procedure FillArray(var v:array of integer);
begin
 v[5]:=12;
end;

procedure TForm1.Button1Click(Sender: TObject);
var v:array of integer;
begin
 SetLength(V, 10);
 FillArray(v);
 if v[5]=12 then beep;
end;


Motaz
0
 
bengoreAuthor Commented:
Thank you Madshi!
0
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