Languages Focus: Member Modifier

Traditional private, protected, public, etc. member modifiers are documented under the member visibility topic of the Cross Reference Encyclopedia. With member modifiers here, we address additional member modifiers such as method and field modifiers.

TCyborg = class(TObject)

public

  procedure Speak(pMessage: String); virtual;

end;

 
TSeries888 = class(TCyborg)

public

  procedure Speak(pMessage: String); override;

end;

Complete Example

The following is the form unit code demonstrating the class above. It assumes a form with a button on it. Note that you add the member modifiers to the member declaration but not when you implement it.

unit MemberModifiersUnit;

 
interface

 
uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, StdCtrls;

type

  TForm1 = class(TForm)

    Button1: TButton;

    procedure Button1Click(Sender: TObject);

  private

    { Private declarations }

  public

    { Public declarations }

  end;

  TCyborg = class(TObject)

  public

    procedure Speak(pMessage: String); virtual;

  end;

  TSeries888 = class(TCyborg)

  public

    procedure Speak(pMessage: String); override;

  end;

var

  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);

var

  Vick: TSeries888;

begin

  Vick := TSeries888.Create;

  Vick.Speak('Hello, I am Vick.');

end;

{ TCyborg }

procedure TCyborg.Speak(pMessage: String);

begin

  //Default cyborg voice.

  ShowMessage(pMessage);

end;

{ TSeries888 }

procedure TSeries888.Speak(pMessage: String);

begin

  //Series 888 voice.

  ShowMessage(pMessage);

end;

end.