Week Numbers

I thought I better move this topic to a new thread, given it's gone off at a complete tangent.... :)

http://www.blitzbasic.com/Community/posts.php?topic=59764

I'm happy to report that I have finally made some headway and I'm hoping that I'm finally on the right track to doing what I need. Will keep you posted - thanks for all the help and encouragement. :)

.

How to find week number:

This is extracted from contracted work so I can't give you the actual source but here's the deal:

1. Find out what day of week 4th of January is. This date is always in week 1 !
2. If 4Th of January is earlier in the week than Thursday we are still (January 1st) in week 52 or 53 of the previous year (Week starting on Monday)

If #2 is true:
3. If in the previous year the 1st of January were a Thursday, then 1st of January this year are week 53 ! (Else 52)
4. If in the previous year the 1st of January were a Wednesday and last year were a leapyear, then 1st of January this year are week 53 ! (Else 52)

I hope this makes sense to you, I have tested it on all years from 1772 (when Gregorian calendar was implemented in Norway) to 2099. (It should be good until 4099!)

And this is my Leap-year function:

'---------------------------------  Leapyear true or not
Function leapyear#(aar#) ' Use year (YYYY) as arguement here
Local tp
If Int(aar/4) = aar/4 Then
					tp=True
					If Int(aar/100) = aar/100 Then
										   tp=False
										   If Int(aar/400) = aar/400 Then tp=True
										   EndIf
					EndIf					
Return tp
End Function

How to find weekday of a specific date:
(Also works between 1772 and 2099)

'------------------------------- DOD (Day of date)
Function dod$(day,month,year) ' (DD,MM,YYYY)
Local d,a,m,y,tp$

a=14-month
a=a/12
y=year-a
m=month+(12*a)-2

d=(day+y+(y/4)-(y/100)+(y/400)+((31*m)/12)) Mod 7

Select d
 Case 0 tp$="Sunday "
 Case 1 tp$="Monday "
 Case 2 tp$="Tuesday"
 Case 3 tp$="Wednesday "
 Case 4 tp$="Thursday"
 Case 5 tp$="Friday "
 Case 6 tp$="Saturday " 
End Select

Return tp$			' Return day
End Function

wedoe,



Damn I wish I was at home so I could check this against my code. :)
I'm pretty sure my code tells me how the 1st of January related to the first Thursday in Jan - which also has to be in week 1.



Thanks for that - I'll see how this relates to my code when I get chance. I got as far as determining whether the 1st of Jan was in week 1, or week 52/53 but not as far as whether it was 52 or 53 - if that makes sense? Nice one though, you've given something extra to work with much appreciated. :)

Thanks for the other codes snippets, again appreciated. I already have functions for determining leapyear and day name. Your leapyear function works very similar to my own - I guess it would really. Thanks again. :)

I also have a snippet somewhere calculating Easter day of any Gregorian year, do you need it ? (Made in BB3D, I think, but should be easy to convert)

I need myself a function for moon-phases for Gregorian years but have not
managed to create anything viable yet, maybe you could help me with this one ?

please include a "Days_until_Xmas()" function

That maybe useful at some point, but I'll leave it for now - I'd like to get the week number thing finished of 1st. Just had a go at it and pretty much got the code to determine the length fof the previous year with the help of your posting - thanks very much. :)



I have to say that means nothing to me TBH, perhaps again it's something I can look into once I've done what I intend to with this date thing first?

bradford6



Take a look at another post I made relating to this...

http://www.blitzbasic.com/Community/posts.php?topic=60038

and in particular the date.DayCount(DD, MM, YYYY) command. You could do what you want with simply...

days_until_xmas% = date.DayCount(25,12,2006>) -date.DayCount()

Is that what you were after? :)

I was being silly... but cool!

could you add a "Days until bradford6's birthday" and have a reminder pop up on everyones PC?

:)

That's OK, I thought maybe you had it covered since you work with calendars right now :o)
It's pretty much the only function I miss in my calendar functions folder...

Glad to help, that's what these forums are for :o)

Not without knowing when your Birthday is no. ;-)

He is not even here!, neither are you Blitzer 101 !

Ah, but then I've not been a BM user for very long. ;-)

Never too late...

Just posted on the age post.

August 20th, 1970

maybe a very intrusive pop-up that automagically links to a 'bradford6 wish list' on Newegg.com

I want to make it easy for folks to buy me fresh PC gear for my b'day

:)