[Overview][Constants][Procedures and functions][Index] | Reference for unit 'DateUtils' (#rtl)

# IsValidDateWeek

Check whether a given year/week/day of the week combination is a valid day.

## Declaration

Source position: dateutil.inc line 102

`function IsValidDateWeek(`
`const AYear: Word;`
`const AWeekOfYear: Word;`
`const ADayOfWeek: Word`
`):Boolean;`

## Arguments

`AYear` |  | Year
`AWeekOfYear` |  | Week in the year
`ADayOfWeek` |  | Day in the week

## Function result

True if the given combination is a valid date, False otherwise.

## Description

IsValidDateWeek returns True if AYear, AWeekOfYear and ADayOfWeek form a valid date indication, or False otherwise.

AYear must be in the range 1..9999 to be valid.

The ADayOfWeek,ADayOfWeek values are checked to see whether the combination falls within the valid range of weeks for AYear.

## See also

IsValidDate |  | Check whether a set of values is a valid date indication.
IsValidTime |  | Check whether a set of values is a valid time indication.
IsValidDateTime |  | Check whether a set of values is a valid date and time indication.
IsValidDateDay |  | Check whether a given year/day of year combination is a valid date.
IsValidDateMonthWeek |  | Check whether a given year/month/week/day of the week combination is a valid day

## Example

    Program Example10;

    { This program demonstrates the IsValidDateWeek function }

    Uses SysUtils,DateUtils;

    Var
      Y,W,D : Word;
      B : Boolean;

    Begin
      For Y:=2000 to 2004 do
        begin
        B:=True;
        For W:=51 to 54 do
          For D:=1 to 7 do
            If B then
              begin
              B:=IsValidDateWeek(Y,W,D);
              If Not B then
                if (D=1) then
                  Writeln(Y,' has exactly ',W,' weeks.')
                else
                  Writeln(Y,' has ',W,' weeks and ',D-1,' days.');
              end;
        end;
    End.

Documentation generated on: May 14 2021