//определение
var as: array of string;
//установка размера
SetLength(as,20);
//вернуть размер
xx:=Length(as);
//цикл
var i: integer;
for i:=0 to Length(as)-1 do
  showmessage(as[i]);
//Уменьшить размер на 4
SetLength(as,Length(as)-4);

var i: integer;
for i:=0 to Length(as)-1 do

var i, sub_i: integer;
 sub_i:=Length(as)-1;
for i:=0 to sub_i do

//может использоваться в цикле
var i: integer;
for i:=Low(aos) to High(aos) do
  showmessage(aos[i]);
,где массив может быть объявлен как:
var aos: array[-4..5] of string;
соотв:
Low(aos)=-4
High(aos)=5

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Button1: TButton;
    Image1: TImage;
    OpenPictureDialog1: TOpenPictureDialog;
    Button2: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
if openpicturedialog1.Execute then
image1.Picture.LoadFromFile(openpicturedialog1.FileName);
end;

function RgbToRed(RGBColor: TColor): TColor;
var
  Red: byte;
begin
  Red := GetRValue(RGBColor);
  Result := RGB(Red, 0, 0);
end;

function RgbToGre(RGBColor: TColor): TColor;
var
  Gre: byte;
begin
  Gre := GetGValue(RGBColor);
  Result := RGB(0, Gre, 0);
end;

function RgbToBlu(RGBColor: TColor): TColor;
var
  Blu: byte;
begin
  Blu := GetBValue(RGBColor);
  Result := RGB(0, 0, Blu);
end;



procedure TForm1.Button2Click(Sender: TObject);
var
  h, w: integer;
  Red: byte;
  Gre: byte;
  Blu: byte;
begin
  for w := 0 to Image1.Width-1 do
    for h := 0 to Image1.Height-1 do

if (Red > Gre) and (Red > Blu) then
Image1.Canvas.Pixels[w, h] :=
 RgbToRed(Image1.Canvas.Pixels[w, h]);
if (Gre > Red) and (Gre > Blu) then
Image1.Canvas.Pixels[w, h] :=
 RgbToGre(Image1.Canvas.Pixels[w, h]);
if (Blu > Red) and (Blu > Gre) then
Image1.Canvas.Pixels[w, h] :=
 RgbToBlu(Image1.Canvas.Pixels[w, h]);

end;

end.

procedure TForm1.Button1Click(Sender: TObject);
var
  i,j: integer;
  r,g,b: cardinal;
  s: string;
  rval,gval,bval: string;
begin
  r:=0;
  g:=0;
  b:=0;
  for i:=0 to Image1.Width-1 do
    for j:=0 to Image1.Height-1 do
  begin
    s:=ColorToString(Image1.Canvas.Pixels[i,j]);
    if pos('cl',s)=1 then Continue;
    bval:=copy(s,4,2);
    gval:=copy(s,6,2);
    rval:=copy(s,8,2);
    if (bval>gval) and (bval>rval) then inc(b) else
    if (gval>bval) and (gval>rval) then inc(g) else
    if (rval>gval) and (rval>bval) then inc(r);
  end;
end;

for i:=0 to Table.RecordCount-1 do ...

var rc: integer;
begin
  rc:=Table.RecordCount;
  for i:=0 to rc-1 do ...

while not Table.eof do...

Test.Quastions[CurrentQ.IndexNonVisual].Text:=frmAddQ.mQText.Text;

TQuastion = record
    Text : TCaption;
    QType : byte;
    TimeSec : integer;
    Answers : CAnswers;
    Code : extended;
  end;

CQuastions = class
    private
      FCount : integer;
      FQuastions : array of TQuastion;
      function GetQuastion(QuastionIndex : integer) : TQuastion;
      Procedure SetQuastion(QuastionIndex : Integer; NewQuastion : TQuastion);
    public
      constructor Create;
      destructor Destroy;
      function GetNewQuastionCode : extended;
      function AddQuastion (Quastion : TQuastion) : boolean;
      function AddQuastionWithAnswer (Quastion : TQuastion) : boolean;
      function ModifyQuastion (OldQuastionIndex : integer; NewQuastion : TQuastion) : boolean;
      function DeleteQuastion (QuastionIndex : integer) : boolean;
      function DeleteAll : boolean;
      property Quastions [QuastionIndex : integer] : TQuastion read GetQuastion write SetQuastion; default;
      property Count : integer read FCount;
  end;

Test.Quastions[CurrentQ.IndexNonVisual].Text:=TCaption(frmAddQ.mQText.Text);