[Lazarus] DateDif function needed

waldo kitty wkitty42 at windstream.net
Tue Nov 12 21:03:29 CET 2013


On 11/11/2013 5:11 PM, Bart wrote:

> type
>    TDaysPerMonth = Array[1..12] of Word;
> function DaysPerMonth(AMonth: Word; IsLeapYear: Boolean): Word;
> const
>    DaysPerMonthNormal: TDaysPerMonth = (31,28,31,30,31,30,31,31,30,31,30,31);
>    DaysPerMonthLeap:   TDaysPerMonth = (31,29,31,30,31,30,31,31,30,31,30,31);
> begin
>    if IsLeapYear then
>      Result := DaysPerMonthLeap[AMonth]
>    else
>     Result := DaysPerMonthNormal[AMonth];
> end;

you do not need any of the above if you change

>      Days := (DaysPerMonth(M1, IsLeapYear(Y2)) - D1) + D2 ;


       Days := (DaysInAMonth(Y2,M1) - D1) + D2;

this because DaysInAMonth returns the correct number of days and takes leapyear 
into account automatically... so there's no reason to duplicate existing code 
with the above type and function ;)

outside of this, what you came up with is almost exactly what i worked my way 
down to as i was working on my own solution... it took me a while and then when 
i saw your post, i was astonished at how the mind works at times :LOL:

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