demo.pas

Delphi面向对象编程思想附书源码 好用哦！

unit Demo;

interface

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

type
  TGPSReceiver = class (TObject)
  public
    procedure Navigate;
  end;
  
  TEngine = class (TObject)
  private
    FCapacity: Integer;
    FPower: Integer;
  public
    procedure start;
    procedure stop;
  end;
  
  TWheel = class (TObject)
  private
    FNo: Integer;
    FSize: Integer;
    FTypeName: string;
    procedure check;
  public
    constructor create(size:Integer;TypeName:string;No:Integer);
  end;
  
  TVehicle = class (TObject)
  protected
    FColor: string;
    FMake: string;
    FTopSpeed: Integer;
    FWheel: TWheel;
    FWheels: TList;
    procedure SlowDown;
    procedure SpeedUp;
    procedure Start;
    procedure Stop;
  end;
  
  TBicycle = class (TVehicle)
  public
    constructor create;
    destructor Destory;
    procedure ride;
  end;
  
  TCar = class (TVehicle)
  private
    FGPSReceiver: TGPSReceiver;
    FTopSpeed: Integer;
  protected
    FEngine: TEngine;
  public
    constructor create(GPS:TGPSReceiver;color:string;Make:string;
            TopSpeed:Integer);
    destructor Destory;
    procedure drive;
    property GPSReceiver: TGPSReceiver read FGPSReceiver write FGPSReceiver;
    property TopSpeed: Integer read FTopSpeed write FTopSpeed;
  end;
  
procedure Register;

implementation

procedure Register;
begin
end;

{
************************************ TWheel ************************************
}
constructor TWheel.create(size:Integer;TypeName:string;No:Integer);
begin
  FSize:=size;
  FTypeName:=TypeName;
  FNo:=No;
  check;
end;

procedure TWheel.check;
begin
  ShowMessage('检查第'+IntToStr(FNo)+'个车轮。型号：'+FTypeName+' 大小：'+IntToStr(FSize));
end;


{
*********************************** TVehicle ***********************************
}
procedure TVehicle.SlowDown;
begin
  ShowMessage('正在减速...');
end;

procedure TVehicle.SpeedUp;
begin
  ShowMessage('正在加速...');
end;

procedure TVehicle.Start;
begin
  ShowMessage('车子开始启动');
end;

procedure TVehicle.Stop;
begin
  ShowMessage('车子停下');
end;

{
*********************************** TBicycle ***********************************
}
constructor TBicycle.create;
var
  i: Integer;
begin
  inherited create;
  FColor:='白色';
  FMake:='永久';
  FTopSpeed:=20;
  FWheels:= TList.Create;
  for i:=1  to 2 do
    FWheels.Add(TWheel.create(21,'B型自行车车轮',i));
end;

destructor TBicycle.Destory;
var
  i: Integer;
begin
  for i:=1  to 2 do
    TWheel(FWheels.Items[i]).Free;
  inherited;
end;

procedure TBicycle.ride;
begin
  start;
  speedUp;
  showmessage('自行车车行驶中...');
  SlowDown;
  Stop;
end;

{
************************************* TCar *************************************
}
constructor TCar.create(GPS:TGPSReceiver;color:string;Make:string;
        TopSpeed:Integer);
var
  i: Integer;
begin
  inherited create;
  FEngine:=TEngine.create;
    //假设最高时速与发动机属性有逻辑关系
  FEngine.Fcapacity:=TopSpeed+1000;
  FEngine.Fpower:=TopSpeed-70;
  FColor:=color;
  FMake:=Make;
  FTopSpeed:=TopSpeed;
  FWheels:= TList.Create;
  ShowMessage(FColor+FMake+'车，最高时速：'+IntToStr(FTopSpeed));
  for i:=1  to 4 do
    FWheels.Add(TWheel.create(36,'A型汽车车轮',i));
  GPSReceiver:=GPS;
end;

destructor TCar.Destory;
var
  i: Integer;
begin
  for i:=1  to 4 do
    TWheel(FWheels.Items[i]).Free;
  FEngine.Free;
  inherited;
end;

procedure TCar.drive;
begin
  start;
  if assigned(GPSReceiver) then  GPSReceiver.Navigate;
  FEngine.start;
  speedUp;
  showmessage('汽车行驶中...');
  SlowDown;
  FEngine.stop;
  Stop;
end;

{
********************************* TGPSReceiver *********************************
}
procedure TGPSReceiver.Navigate;
begin
  showmessage('使用GPS导航');
end;

{
*********************************** TEngine ************************************
}

procedure TEngine.start;
begin
  ShowMessage(inttostr(Fcapacity)+'cc,'+inttostr(Fpower)+'匹马力的发动机发动了!');
end;

procedure TEngine.stop;
begin
  ShowMessage('发动机关闭了');
end;

end.