unit uSayHello;

interface

uses

  SysUtils,

  Windows,

  Messages,

  Classes,

  Graphics,

  Controls,

  Forms,

  Dialogs;

type

  // IInterface表示申明了一些函数，自己本身没有实现部分，需要由继承它的类来实现函数

  ISpeakChinese = interface(IInterface)

    function SayHello: string;

  end;

  // IInterface表示申明了一些函数，自己本身没有实现部分，需要由继承它的类来实现函数

  ISpeakEnglish = interface(IInterface)

    function SayHello: string;

  end;

  // 人类

  TMan = class(TInterfacedObject)

  private

    // 姓名

    FName: string;

  public

    property Name: string read FName write FName;

  end;

  // 中国人，继承了人类和说汉语

  TChinese = class(TMan, ISpeakChinese)

  private

    // ISpeakChinese中定义的函数，序号在继承类中实现

    function SayHello: string;

  end;

  TAmerican = class(TMan, ISpeakEnglish)

  private

    // ISpeakChinese中定义的函数，序号在继承类中实现

    function SayHello: string;

  end;

  // 美籍华人 ，继承了人类，汉语和英语

  TAmericanChinese = class(TMan, ISpeakChinese, ISpeakEnglish)

  public

    constructor create;

    // ISpeakChinese中定义的函数，序号在继承类中实现

    function SayHello: string;

  end;

implementation

{

  ********************************** TAmerican ***********************************

}

function TAmerican.SayHello: string;

begin

  result := 'Hello!';

end;

{

  *********************************** TChinese ***********************************

}

function TChinese.SayHello: string;

begin

  result := '你好！';

end;

{

  ******************************* TAmericanChinese *******************************

}

constructor TAmericanChinese.create;

begin

  name := 'Tom Wang';

end;

function TAmericanChinese.SayHello: string;

var

  Dad: ISpeakChinese;

  Mum: ISpeakEnglish;

begin

  Dad := TChinese.create;

  Mum := TAmerican.create;

  // 调用说中文和说英文方法

  result := Dad.SayHello + Mum.SayHello;

end;

end.

unit frmMain;

interface

uses

  Windows,

  Messages,

  SysUtils,

  Variants,

  Classes,

  Graphics,

  Controls,

  Forms,

  Dialogs,

  StdCtrls,

  ExtCtrls;

type

  TForm1 = class(TForm)

    Button1: TButton;

    LabeledEdit1: TLabeledEdit;

    procedure Button1Click(Sender: TObject);

  private

    { Private declarations }

  public

    { Public declarations }

  end;

var

  Form1: TForm1;

implementation

uses

  uSayHello;

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);

var

  Tom: TAmericanChinese;

begin

  // 创建美籍华人类

  Tom := TAmericanChinese.Create;

  try

    LabeledEdit1.text := Tom.Name;

    // 输出

    ShowMessage(Tom.sayhello);

  finally

    Tom.Free;

  end;

end;

end.