Project: DYNARR.DPR

Project Structure

• DYNARR.DPR
• DYNARRF.PAS
• DYNARRF.DFM

program DynArr;

uses
  Forms,
  DynArrF in 'DynArrF.pas' {Form1};

{$R *.RES}

begin
  Application.Initialize;
  Application.CreateForm(TForm1, Form1);
  Application.Run;
end.

unit DynArrF;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls;

type
  TForm1 = class(TForm)
    btnFill: TButton;
    btnAlias: TButton;
    btnSet: TButton;
    btnGrow: TButton;
    btnGet: TButton;
    procedure btnFillClick(Sender: TObject);
    procedure btnAliasClick(Sender: TObject);
    procedure btnSetClick(Sender: TObject);
    procedure btnGrowClick(Sender: TObject);
    procedure btnGetClick(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

var
  Array1, Array2: array of Integer;

procedure TForm1.btnFillClick(Sender: TObject);
var
  I: Integer;
begin
  // fill
  for I := Low (Array1) to High (Array1) do
    Array1 [I] := I;
end;

procedure TForm1.btnSetClick(Sender: TObject);
begin
  Array1 [99] := 100;
end;

procedure TForm1.btnGrowClick(Sender: TObject);
begin
  // grow keeping existing values
  SetLength (Array1, 200);
end;

procedure TForm1.btnGetClick(Sender: TObject);
begin
  // extract
  Caption := IntToStr (Array1 [99]);
end;

procedure TForm1.btnAliasClick(Sender: TObject);
begin
  // alias
  Array2 := Array1;
  // change one (both change)
  Array2 [99] := 1000;
  // show the other
  Caption := IntToStr (Array1 [99]);

  if Array1 = Array2 then
    Beep;

  // truncate first array
  Array1 := Copy (Array2, 0, 10);
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  // allocate
  SetLength (Array1, 100);
end;

end.

object Form1: TForm1
  Left = 197
  Top = 108
  Width = 203
  Height = 166
  ActiveControl = btnFill
  BorderWidth = 1
  Caption = 'DynArr'
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'MS Sans Serif'
  Font.Style = []
  OldCreateOrder = True
  OnCreate = FormCreate
  PixelsPerInch = 96
  TextHeight = 13
  object btnFill: TButton
    Left = 16
    Top = 24
    Width = 75
    Height = 25
    Caption = '&Fill'
    TabOrder = 0
    OnClick = btnFillClick
  end
  object btnAlias: TButton
    Left = 16
    Top = 104
    Width = 161
    Height = 25
    Caption = '&Create alias and truncate'
    TabOrder = 1
    OnClick = btnAliasClick
  end
  object btnSet: TButton
    Left = 104
    Top = 24
    Width = 75
    Height = 25
    Caption = '&Set value'
    TabOrder = 2
    OnClick = btnSetClick
  end
  object btnGrow: TButton
    Left = 16
    Top = 56
    Width = 75
    Height = 25
    Caption = '&Grow'
    TabOrder = 3
    OnClick = btnGrowClick
  end
  object btnGet: TButton
    Left = 104
    Top = 56
    Width = 75
    Height = 25
    Caption = 'Get &value'
    TabOrder = 4
    OnClick = btnGetClick
  end
end