如何得到本周的第一天？

Question

如何得到本周的第一天？
例如知道
日期：2003-3-11 
得到日期所在周的得一天，周一

Answer 1

unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, DateUtils;type
  TMainForm = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;var
  MainForm: TMainForm;implementation{$R *.dfm}procedure TMainForm.Button1Click(Sender: TObject);
begin
   ShowMessage(DateToStr(StartOfTheWeek(StrToDate('2003-3-11'))));
end;end.

Answer 2

StartOfAWeek(const ayear,aweekyear:word,const adayofweek:word=1):tdatetime
如：
var ayear,aweekofyear,adayofweek:word;
begin
 ayear:=2001;//年
 aweekofyear:=2;//第二周
 adayofweek:=1;//第一天 
ShowMessage(DatetimeToStr(StartOfAWeek(ayear,aweekofyear,adayofweek)));
end;返回是2001/01/08 AM 12:00:00