Re: RPG date functions vs. Excel date functions

[Vernon Hamberg <vhamberg@xxxxxxxxxxxxxxx>]

That's what I was trying to remember - Joel Spolsky writes some good 
stuff about programming, IMHO.

On 9/17/2015 12:13 PM, Lance Gillespie wrote:
> Maybe it has something to do with the famous "Excel data error that isn't"
> http://www.joelonsoftware.com/items/2006/06/16.html
>
>
> date: Thu, 17 Sep 2015 11:56:52 -0500
> from: "Englander, Douglas" <Douglas_Englander@xxxxxxxxxxxxx>
> subject: RPG date functions vs. Excel date functions
>
>
> I am reading an excel spreadsheet via RPG (using Scott Klements routines). There is one cell containing the number 40999, which excel interprets as March 31, 2012. The 40999 representing the number of days from January 1, 1900 (January 1, 1900 would be represented as 1).
>
> If I initialize a base date in RPG (a *ISO date field) to December 31, 1899, and add the excel number to it (converted to days), I am expecting to get the date that excel is converting 40999 to (i.e. I would expect RPG to calculate December 31, 1899 + %days(40999) to be March 31, 2012 also). However, no matter how I do it, RPG calculates December 31, 1899 + %days(40999) to be April 1, 2012.
>
> Does anyone have any idea as to why the calculations differ by one day? I trust IBM over Microsoft, and would take the April 1, 2012 date, but I would like to know why the two dates are calculated differently.
>
> Thank you,
>
> Doug
>
>
>
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