unit Dates;

interface

type
  TDate = class
  private
    fDate: TDateTime;
    procedure SetDay(const Value: Integer);
    procedure SetMonth(const Value: Integer);
    procedure SetYear(const Value: Integer);
    function GetDay: Integer;
    function GetMonth: Integer;
    function GetYear: Integer;
  public
    constructor Create; overload;
    constructor Create (y, m, d: Integer); overload;
    procedure SetValue (y, m, d: Integer); overload;
    procedure SetValue (NewDate: TDateTime); overload;
    procedure Assign(Source: TDate);

    function LeapYear: Boolean;
    procedure Increase (NumberOfDays: Integer = 1);
    procedure Decrease (NumberOfDays: Integer = 1);
    function GetText: string;

    property Year: Integer read GetYear write SetYear;
    property Month: Integer read GetMonth write SetMonth;
    property Day: Integer read GetDay write SetDay;
  end;

  TNewDate = class (TDate)
  public
     function GetText: string;
  end;

implementation

uses
  SysUtils, DateUtils;

procedure TDate.Assign (Source: TDate);
begin
  fDate := Source.fDate;
end;

procedure TDate.SetValue (y, m, d: Integer);
begin
  fDate := EncodeDate (y, m, d);
end;

function TDate.LeapYear: Boolean;
begin
  Result := IsInLeapYear(fDate);
end;

procedure TDate.Increase (NumberOfDays: Integer = 1);
begin
  fDate := fDate + NumberOfDays;
end;

function TDate.GetText: string;
begin
  GetText := DateToStr (fDate);
end;

procedure TDate.Decrease (NumberOfDays: Integer = 1);
begin
  fDate := fDate - NumberOfDays;
end;

constructor TDate.Create (y, m, d: Integer);
begin
  fDate := EncodeDate (y, m, d);
end;

constructor TDate.Create;
begin
  fDate := Date;
end;

procedure TDate.SetValue(NewDate: TDateTime);
begin
  fDate := NewDate;
end;

procedure TDate.SetDay(const Value: Integer);
begin
  fDate := RecodeDay (fDate, Value);
end;

procedure TDate.SetMonth(const Value: Integer);
begin
  fDate := RecodeMonth (fDate, Value);
end;

procedure TDate.SetYear(const Value: Integer);
begin
  fDate := RecodeYear (fDate, Value);
end;

function TDate.GetDay: Integer;
begin
  Result := DayOf (fDate);
end;

function TDate.GetMonth: Integer;
begin
  Result := MonthOf (fDate);
end;

function TDate.GetYear: Integer;
begin
  Result := YearOf (fDate);
end;

{ TNewDate }

function TNewDate.GetText: string;
begin
  GetText := FormatDateTime ('dddddd', fDate);
end;

end.