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**Scott Turchin** · 11 Mar 2001, 05:43 AM

Perhaps this will help:

Code:

Function DayOfTheWeek() Export As String
     '// get date format in "dddd, MMMM dd, yyyy"
     '// e.g. Monday, June 26, 2000
     Local uTime As SYSTEMTIME
     Local lNum As Long
     Local saDay As Asciiz * 64
     Local saMonth As Asciiz * 64

     GetLocalTime uTime

     If uTime.wDayOfWeek = 0 Then
         ' this is Sunday, work out separately
         lNum = &H30
     Else
         lNum = &H2A + (uTime.wDayOfWeek) -1
     End If

     GetLocaleInfo %LOCALE_USER_DEFAULT, lNum, saDay, SizeOf(saDay)
     lNum = &H38 + (uTime.wMonth - 1)
     GetLocaleInfo %LOCALE_USER_DEFAULT, lNum, saMonth, SizeOf(saMonth)
     Function = Trim$(saDay & ", " & saMonth & " " & Trim$(Str$(uTime.wDay)) & ", " & Trim$(Str$(uTime.wYear)))

End Function

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Scott

**Bern Ertl** · 11 Mar 2001, 10:18 AM

You might try converting :

TradeStation date -> Systemtime value -> Filetime value

<perform math on Filetime value>

Filetime value -> Systemtime value -> TradeStation date

Code:

#INCLUDE "WIN32API.INC"


%OneDay      =   864000000000&&


UNION MathTime
   Q AS QUAD
   F AS FILETIME
END UNION


DIM ST AS SYSTEMTIME
DIM MT AS MathTime
DIM DaysOfWeek$(6)

DaysOfWeek$(0) = "Sun" : DaysOfWeek$(1) = "Mon" 'etc....

ST.wYear = Year
ST.wMonth = Month
ST.wDay = Day


SystemTimeToFileTime ST, MT.F


MT.Q = MT.Q + 30 * %OneDay


FileTimeToSystemTime MT.F, ST

Day$ = DaysOfWeek$( ST.wDayOfWeek)

Year = ST.wYear
Month = ST.wMonth
Day = ST.wDay

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Bernard Ertl

[This message has been edited by Bern Ertl (edited March 11, 2001).]

**Eric Pearson** · 11 Mar 2001, 12:39 PM

Mike --

> This App produces an ascii file of julian
> dates and days of the week from 97 - 04
> that is perfect except for one day - Feb 24 2000!

Sorry, it isn't perfect. It skips days of the week on...

05/30/1997
12/16/1997
03/26/1998
10/12/1998

...and so on.

Your Julian Date functions appear to be working correctly. All you have to do is take the Julian Date MOD 7 to get the day of the week, offset by 1. In other words...

Code:

(Julian+1) MOD 7 = Day of Week from 0 (Sunday) to 6 (Saturday).

-- Eric

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**Egbert Zijlema** · 11 Mar 2001, 01:31 PM

A complete set of Julian functions can be found at www.basicguru.com/zijlema/ .
It is for DOS, but it's rather easy to 'translate' it to PB for Windows.

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www.basicguru.com/zijlema/

[This message has been edited by Egbert Zijlema (edited March 11, 2001).]

**Mike Trader** · 11 Mar 2001, 02:07 PM

Bern, Scott and Egbert, Thx nut I dont want to go thru yet more conversions if I can possible help it. I am so close.

Eric
Youre right it skips other dates too. I really dont get this ..

I tried substituting
FUNCTION DayOfWeek( BYVAL TDate AS LONG ) AS LONG
LOCAL TSDateJul AS LONG
TSDateJul = DateToJulian(TDate)
DayOfWeek = (TSDateJul+1) MOD 7
END FUNCTION
All this does is shift the days of the week relative to the Julian date. The fundamental problem still persists.

I have checked and rechecked my Julian<->Date conversions. They are clean. As you can see the julian Numbers are in perfect sequence and the dates are correct.

Yet the day of the week has these wierd hiccups every once in while!?

------------------
Kind Regards
Mike

**Eric Pearson** · 11 Mar 2001, 02:28 PM

Mike --

I think you're mistaken. I changed your program like this:

Code:

'Day = DayOfWeek(i)  'remove this
Jul = DateToJulian(Date)
Day = (Jul+1) MOD 7  'add this

...and it produces the correct day of the week for every date. No hiccups, coughs, sneezes...

-- Eric

------------------
Perfect Sync Development Tools
Perfect Sync Web Site
Contact Us: mailto:[email protected][email protected]</A>

[This message has been edited by Eric Pearson (edited March 11, 2001).]

**Mike Burns** · 11 Mar 2001, 03:15 PM

Mike,

In

Day = DayOfWeek(i)

i was converted to Julian before the loop

JStart = DateToJulian(970101)

the DayOfWeek looks like it is trying to convert i to Julian
again. Did you mean to pass it Date? Or you need to comment out
the DateToJulian in the DayOfWeek function and try TDate Mod 7.

Mike

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**Russ Srole** · 11 Mar 2001, 06:33 PM

Mike,

Here's a trick I used in PB for Dos. It seems to work fine in
windows as well The thing you have to do is save the current
date BEFORE starting you loop. Then restore it when you've
finished. The only problem you could encounter is if you start
your loop before midnight and end it after. In that case you
would set the date for yesterday. If that is a concern then
check the time before and after the loop and if time < old_time
then reset the date then incr by one.

SUB Incr_date
LOCAL last_date$, temp$, m$, d$, y$, x&
last_date$ = DATE$
temp$ = DATE$
d$ = MID$(temp$, 4, 2)
x = VAL(d$)
INCR x
d$ = FORMAT$(x, "00")
MID$(temp$, 4,2) = d$
DATE$ = temp$
IF DATE$ <> last_date$ THEN EXIT SUB

' new month
MID$(temp$, 4, 2) = "01" ' 1st day of month
m$ = LEFT$(temp$, 2)
x = VAL(m$)
INCR x
m$ = FORMAT$(x, "00")
MID$(temp$, 1) = m$
DATE$ = temp$
IF DATE$ <> last_date$ THEN EXIT SUB

' new year
MID$(temp$, 1, 2) = "01" 'Jan
y$ = RIGHT$(temp$, 4)
x = VAL(y$)
INCR x
y$ = FORMAT$(x, "0000")
MID$(temp$, 7) = y$
DATE$ = temp$
END SUB

Hope that helps

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**Semen Matusovski** · 11 Mar 2001, 09:26 PM

I like MSDN sample:

Code:

   Function AstroDay(year As Long, month As Long, day As Long) As Long
      Dim y As Double
      y = year + (month - 2.85) / 12
      AstroDay = Int(Int(Int(367 * y) - 1.75 * Int(y) + day) -0.75 * Int(0.01 * y)) + 1721116
   End Function

Sample of usage

Code:

   Function PbMain
      Select Case (AstroDay(2001, 1, 17) Mod 7) ' Day of week
         Case 0: Print "Sunday"
         Case 1: Print "Monday"
         Case 2: Print "Tuesday"
         Case 3: Print "Wednesday"
         Case 4: Print "Thursday"
         Case 5: Print "Friday"
         Case 6: Print "Saturday"
      End Select
      Print Astroday(2001, 1, 17) - Astroday(2000, 12, 31) ' No. of days
      WaitKey$
   End Function

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**Mike Doty** · 22 May 2023, 09:53 PM

Astroday
Post number 10 correction (there is a reason for both dates)

Julian Date - PowerBASIC Peer Support Community

https://forum.powerbasic.com/forum/user-to-user-discussions/programming/797948-julian-date

I just happened to be comparing some Julian date functions I found in the forums and noticed a difference ... the values 1721116 and 1721119. Which is correct? Outside the forum I've found both used. Function AstroDay(TheDate$) As Long 'MM-DD-YYYY Local y As Double, Year, Month, Day As Long Year =

Can also be changed in Roca includes. afxtime.inc and cafxtime.inc

Code:

Function AstroDay(year As Long, month As Long, day As Long) As Long
  Dim y As Double
  y = year + (month - 2.85) / 12
  AstroDay = Int(Int(Int(367 * y) - 1.75 * Int(y) + day) -0.75 * Int(0.01 * y)) + 1721119  '1721116
End Function

Announcement

Day Of Week from Julian Date - Mystery "feature"

Day Of Week from Julian Date - Mystery "feature"

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