求某天是星期几的函数？(20分)

请问delphi中有没有 求某天是星期几的函数？有的话是什么？
没有的话应怎么写?

dayofweek()
返回的是整数形的！

函数DayofWeek
范例：
procedure TForm1.Button1Click(Sender: TObject);

var
ADate: TDateTime;
days: array[1..7] of string;
begin
days[1] := 'Sunday';
days[2] := 'Monday';
days[3] := 'Tuesday';
days[4] := 'Wednesday';
days[5] := 'Thursday';
days[6] := 'Friday';
days[7] := 'Saturday';
ADate := StrToDate(Edit1.Text);
ShowMessage(Edit1.Text + ' is a ' + days[DayOfWeek(ADate)];
end;

接受答案了.

函数DayofWeek
范例：
procedure TForm1.Button1Click(Sender: TObject);

var
ADate: TDateTime;
days: array[1..7] of string;
begin
days[1] := 'Sunday';
days[2] := 'Monday';
days[3] := 'Tuesday';
days[4] := 'Wednesday';
days[5] := 'Thursday';
days[6] := 'Friday';
days[7] := 'Saturday';
ADate := StrToDate(Edit1.Text);
ShowMessage(Edit1.Text + ' is a ' + days[DayOfWeek(ADate)];
end;