SysUtils.DayOfWeek Function

Returns the day of the week for a specified date.

Pascal

function DayOfWeek(const DateTime: TDateTime): Word;

C++

Word DayOfWeek(const TDateTime DateTime);

File

SysUtils

Description

DayOfWeek returns the day of the week of the specified date as an integer between 1 and 7, where Sunday is the first day of the week and Saturday is the seventh.

Note: DayOfWeek is not compliant with the ISO 8601 standard, which defines Monday as the first day of the week. For an ISO 8601 compliant version, use the DayOfTheWeek function instead.

C++ Examples:

Copy Code

/*
This example uses an edit box and a button on a form. When
the user enters a date in the edit box in the format
associated with the current locale (for example MM/DD/YY
format in the US), the string entered is converted to a
TDateTime value. This value is used to indicate the day of
the week the date represents.
*/
void __fastcall TForm1::Button1Click(TObject *Sender)
{
  char days[7][10] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday" };
  TDateTime dtDate = StrToDate(Edit1->Text);
  ShowMessage(Edit1->Text + AnsiString(" is a ") + days[dtDate.DayOfWeek() - 1]);
}

Delphi Examples:

Copy Code

{
This example uses an edit box and a button on a form. When
the user enters a date in the edit box in the format
associated with the current locale (for example MM/DD/YY
format in the US), the string entered is converted to a
TDateTime value. This value is used to indicate the day of
the week the date represents.
} 
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[SysUtils.DayOfWeek(ADate)]);
end;