How to pass single element of array to procedure?

Question

Example

procedure TForm1.ButtonClick(Sender: TObject);
var x:integer;
begin
   SetLength(MyArray,10)
   for x:=0 to 9 do FillWithRandomNumbers(MyArray[x]);
end;

Procedure FillWithRandomNumbers(var MyArray: Array of double);
begin
  MyArray:=Random; //<-I have no idea what to do here :(
end;

As you can see I'm trying to pass single element to procedure in order to perform some task on specified array cell. For example procedure FillWithRandomNumbers should take MyArray[2] and fill this cell with random number.

David Heffernan · Accepted Answer · 2016-08-04 18:38:14Z

4

You want to pass a single array element, yet your procedure expects a full array. To directly answer your actual question, your procedure should be defined as:

Procedure FillWithRandomNumber(var Value: double);  
begin
  Value:= Random;
end;

procedure TForm1.ButtonClick(Sender: TObject);
var x:integer;
begin
   SetLength(MyArray,10)
   for x:=0 to 9 do FillWithRandomNumber(MyArray[x]);
end;

Or you could do it like this instead:

procedure TForm1.ButtonClick(Sender: TObject);
begin
   SetLength(MyArray, 10);
   FillWithRandomNumbers(MyArray);
end;

Procedure FillWithRandomNumbers(var SomeArray: Array of double);
var
  X: Integer;
begin
  for X := Low(SomeArray) to High(SomeArray) do begin
    SomeArray[X] := Random;
  end;
end;

Or to be even more simple, just don't use a procedure at all:

procedure TForm1.ButtonClick(Sender: TObject);
var
  X: Integer;
begin
  SetLength(MyArray, 10);
  for X := 0 to High(Array) do begin
    MyArray[X]:= Random;
  end;
end;

edited Aug 4, 2016 at 18:38

David Heffernan

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answered Aug 4, 2016 at 17:16

Jerry Dodge

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2 Comments

Atak_Snajpera Over a year ago

Yes I know It can be done simpler. It was just an extreme simple example. Thank you for first solution.

mezen Over a year ago

Another possibility is to use the result of a funciton: function GetRandomNumber; begin Result:=Random; end; procedure TForm1.ButtonClick(Sender: TObject); var x:integer; begin SetLength(MyArray,10) for x:=0 to 9 do MyArray[x] := GetRandomNumber(); end;

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