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unit uWeatherReport;

interface

uses
Classes, SysUtils;

type
TObserver = class; { ForwardÉùÃ÷£¬´´½¨Á½¸öÏ໥ÒÀÀµµÄÀà }

{ ³éÏóÖ÷Ìâ }
TSubject = class(TObject)
procedure RegisterObserver(aObserver: TObserver); virtual; abstract;
procedure RemoveObserver (aObserver: TObserver); virtual; abstract;
procedure NotifyObserver; virtual; abstract;
end;

{ ¾ßÌåÖ÷Ìâ }
TWeatherData = class(TSubject)
private
FObservers: TList;
FTemp : Integer;
FHumidity : Integer;
FPresssure: Integer;
public
constructor Create;
destructor Destroy; override;
procedure RegisterObserver(aObserver: TObserver); override;
procedure RemoveObserver (aObserver: TObserver); override;
procedure NotifyObserver; override;
procedure MeasurementsChanged;
procedure SetMeasurements(aTemp, aHumidity, aPresssure: Integer);
end;

{**************************************************************************}

{ ³éÏó¹Û²ìÕß }
TObserver = class(TObject)
procedure UpDate(Temp, Humidity, Presssure: Integer); virtual; abstract;
procedure Display; virtual; abstract;
end;

{ ¾ßÌå¹Û²ìÕß }
TCurrentConditionsDisplay = class(TObserver)
private
FTemp : Integer;
FHumidity : Integer;
FWeatherData: TSubject;
public
constructor Create(aWeatherData: TSubject);
destructor Destroy; override;
procedure UpDate(aTemp, aHumidity, aPresssure: Integer); override;
procedure Display; override;
end;

implementation

{ TWeatherData }

constructor TWeatherData.Create;
begin
FObservers := TList.Create;
end;

destructor TWeatherData.Destroy;
begin
FObservers.Clear;
FreeAndNil(FObservers);
inheri