FreeProfan

Set("ErrorLevel", 0)
declare date1$,date2$,Diff%
'Eingelesene values zB
Datum1$=20161001
Datum2$=20161030
'+----------------------------------------------

Proc DeltaTage_DB_Format

    '+----------------------------------------------
    'accounts amount of Meet between 2 Datumswerten
    'Parameter: beginning, end in Datenbankformat
    'Return difference days Integer
    Parameters From$,To$
    Return dt("DaysBetween", dt("setdate",DToC$(From$)), dt("setdate",DToC$(To$)))

endproc'DeltaTage_DB_Format

' Hauptprogramm
Diff% = DeltaTage_DB_Format(date1$,date2$)
messagebox(st$(diff%),"Differenz-Tage",0)

Set("ErrorLevel", 0)
declare date1$,date2$,Diff%
'Eingelesene values zB
Datum1$=20161001
Datum2$=20161030
'+----------------------------------------------

Proc DeltaTage_DB_Format

    '+----------------------------------------------
    'accounts amount of Meet between 2 Datumswerten
    'Parameter: beginning, end in Datenbankformat
    'Return difference days Integer
    Set("ErrorLevel", -1)
    Parameters From$,To$
    Var worth$ = dt("DaysBetween", dt("setdate",DToC$(From$)), dt("setdate",DToC$(To$)))
    'print %error

    If %Error > 0

        'print "Fehler"
        worth$ = "Fehler"

    EndIf

    Set("ErrorLevel", 0)
    Return worth$

endproc'DeltaTage_DB_Format

' Hauptprogramm
Var Result$ = DeltaTage_DB_Format(date1$,date2$)

If Result$ = "Fehler"

    '...

Else

    diff% = Val(Result$)
    'here then The further treatment

EndIf

Waitinput

Proc MakeFullYear

    ' filling the (possible) forgotten centenary on.
    ' Y = MakeFullYear( Y )
    Parameters Y%
    Declare ThisCentury%, ThisCenturyRange%
    ThisCentury% = 20
    ThisCenturyRange% = 29'2000 - 2029, otherwise 1930 - 1999

    If Y% < 100

        Casenote Between(ThisCenturyRange%,0,99) : ThisCenturyRange% = 29
        Casenote Between(ThisCentury%,16,39) : ThisCentury% = Int(dt("GetYear",!now) / 100)

        If Y% <= ThisCenturyRange%

            ' News year
            Y% = Y% + (ThisCentury% * 100)

        Else

            ' Vorjahr
            Y% = Y% + ((ThisCentury% - 1) * 100)

        EndIf

    EndIf

    Return Y%

ENDPROC

Proc LastDayInMonth

    ' supply whom last day the month's.
    ' Ultimo = LastDayInMonth( Mo, Y )
    ' -1 = Error
    Parameters Mo%, Y%
    Declare Leap%, Ultimo%, LDiM%[12]
    LDiM%[0]=0:LDiM%[1]=31:LDiM%[2]=28:LDiM%[3]=31:LDiM%[4]=30:LDiM%[5]=31:LDiM%[6]=30
    LDiM%[7]=31:LDiM%[8]=31:LDiM%[9]=30:LDiM%[10]=31:LDiM%[11]=30:LDiM%[12]=31
    Ultimo% = -1
    Case Y% < 100 : Y% = MakeFullYear(Y%)
    Leap% = if((((Y% mod 4) = 0) and ((Y% mod 100) <> 0)) or ((Y% mod 400) = 0), 1, 0)' isLeapYear(Y)
    Case Between(Mo%,1,12) : Ultimo% = LDiM%[Mo%] + if( (Mo% = 2) and (Leap% = 1), 1, 0)
    Return Ultimo%

ENDPROC

Proc isValidDate

    ' checks day,month,year on Gültigkeit.
    ' ok = isValidDate(D,Mo,Y)
    ' 0 = invalid (false)
    ' 1 = valid (true)
    Parameters D%,Mo%,Y%
    Declare ok%
    ok% = 0
    Case Between(Y%,1600,3999, Mo%,1,12, D%,1,(LastDayInMonth(Mo%,Y%))) : Inc ok%
    Return ok%

ENDPROC

Proc GetDayDB

    ' Zieht whom day a DB-date.
    ' Day = GetDayDB( DB )
    Parameters DB%
    Return DB% mod 100

ENDPROC

Proc GetMonthDB

    ' Zieht whom month a DB-date.
    ' Month = GetMonthDB( DB )
    Parameters DB%
    Return Int((DB% mod 10000) / 100

ENDPROC

Proc GetYearDB

    ' Zieht the year a DB-date.
    ' Year = GetYearDB( DB )
    Parameters DB%
    Return Int(DB% / 10000)

ENDPROC

Proc SetDB

    ' prepares from day,month,year one DB-date with Gültigkeitsprüfung.
    ' DB = SetDB(D,Mo,Y)
    ' -1 = Error
    Parameters D%,Mo%,Y%
    Declare DB%
    DB% = -1
    Case Y% < 100 : Y% = MakeFullYear(Y%)
    Case isValidDate(D%,Mo%,Y%) : DB% = Y% * 10000 + Mo% * 100 + D%
    Return DB%

ENDPROC