How do you convert a Date to Julian Date

[Mike Trader]

I need to do some calculations with dates (adding and subtracting days mostly). I can do this in tradestation by using a function they call DateToJulian(). I then do my calculations and convert the result back using the inverse function, you guessed it JulianToDate()! (See below for definitions)

Now that I am converting all my code to PB i have to write these two functions. But short of a lookup table and some kind of compenstion for leap years I cant think of slick way to do it.

Are there any Win API calls that might do this?

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DateToJulian Function:

Returns the Julian date for the specified calendar date.

DateToJulian(cDate) ;

(cDate) is a numeric expression representing the date in the format YYYYMMDD

Remarks

If a specific date is entered for the numeric expression, it must be a valid date between January 1, 1901 and February 28, 2150

Examples

DateToJulian(980804) returns a value of 36011 for the date August 4, 1998.

DateToJulian(991024) returns a value of 36457 for the date October 24, 1999
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JulianToDate Function:

Returns the calendar date for the specified Julian date.

JulianToDate(jDate) ;
(jDate) is a numeric expression representing the Julian date.

Examples

JulianToDate(36011) returns a value of 19980804 for the date August 4, 1998.

JulianToDate(36457) returns a value of 19991024 for the date October 24, 1999.
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Kind Regards
Mike

[Lance Edmonds]

there are a bunch of julian date functions in the source code forum... a quick search for "julian" reveals at least three postings. there may be more in the srccode archive forum too.

for example:
http://www.powerbasic.com/support/pb...ad.php?t=23600

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lance
powerbasic support
mailto:[email protected][email protected]</a>

[Bern Ertl]

You might also investigate the Windows API SystemTime & FileTime
structures and their related functions (FileTimeToSystemTime,
SystemTimeToFileTime, etc.)

The FileTime structure is really just a QUAD value which is similar
to a Julian, but not exactly the same. You can perform math on the
dates with it, however.




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Bernard Ertl