Seems so simple but, i'm trying to get ones exact age, on any given day, using their internal birthday. If I do the obvious, subtract internal birthdate from current date and divide by 36525, I get the accurate year but months and days comes out as a fraction of a year...

Anyone have an easy calc for this?

Thanks

------------------------------
Kathleen Hambrick
PROGRAMMER
William C Earhart Co Inc
Portland OR United States
------------------------------

Hi Kathleen!

It's been a few years (decades?) since I did something along those lines.  I don't have the code handy, but if I remember correctly, it used a combination of the REM() and MOD() functions.

------------------------------
Brian Paige
Enterprise Systems Manager
Serta /Simmons Bedding LLC
Doraville GA United States
------------------------------

---

Seems so simple but, i'm trying to get ones exact age, on any given day, using their internal birthday. If I do the obvious, subtract internal birthdate from current date and divide by 36525, I get the accurate year but months and days comes out as a fraction of a year...

Anyone have an easy calc for this?

Thanks

------------------------------
Kathleen Hambrick
PROGRAMMER
William C Earhart Co Inc
Portland OR United States
------------------------------

Hi, I wrote this almost a decade ago, I only needed to go to years and months but days could be added easily.

I'm sure it could possibly be written a little simpler also (UK date format).

SUBROUTINE CalculateDateDifference (PeriodStartInternalDate, PeriodEndInternalDate, ElapsedPeriod)
$INCLUDE CONSTANTS.BP DelimiterConstants

* Calculate the number or years and months that have elapsed between the supplied start and end
* dates (each expressed in internal format) and return a textual description of that elapsed
* period. If the period end date is left blank, then today's date will be assumed.

LastDaysOfMonths = 31:AM:28:AM:31:AM:30:AM:31:AM:30:AM:31:AM:31:AM:30:AM:31:AM:30:AM:31
IF UNASSIGNED(PeriodEndInternalDate) THEN
PeriodEndInternalDate = ''
END
IF PeriodStartInternalDate = "" THEN
ElapsedPeriod = "Cannot Determine"
END ELSE
IF PeriodEndInternalDate = "" THEN
PeriodEndInternalDate = DATE()
END
PeriodEndDate = OCONV(PeriodEndInternalDate, "D/")
PeriodEndDay = FIELD(PeriodEndDate, "/", 1)
PeriodEndMonth = FIELD(PeriodEndDate, "/", 2)
PeriodEndYear = FIELD(PeriodEndDate, "/", 3)
LastDayOfMonth = LastDaysOfMonths<PeriodEndMonth>
PeriodStartDate = OCONV(PeriodStartInternalDate,"D/")
PeriodStartDay = FIELD(PeriodStartDate, "/", 1)
PeriodStartMonth = FIELD(PeriodStartDate, "/", 2)
PeriodStartYear = FIELD(PeriodStartDate, "/", 3)
CalculatedYearsElapsed = PeriodEndYear - PeriodStartYear
CalculatedMonthsElapsed = PeriodEndMonth - PeriodStartMonth
CalculatedDaysElapsed = PeriodEndDay - PeriodStartDay
IF (CalculatedMonthsElapsed < 0) OR (CalculatedMonthsElapsed = 0 AND CalculatedDaysElapsed < 0) THEN
CalculatedYearsElapsed = CalculatedYearsElapsed - 1
END
IF CalculatedMonthsElapsed < 0 THEN
CalculatedMonthsElapsed = 12 + CalculatedMonthsElapsed
END
IF CalculatedDaysElapsed < 0 AND PeriodEndDay # LastDayOfMonth THEN
CalculatedMonthsElapsed = CalculatedMonthsElapsed - 1
IF CalculatedMonthsElapsed < 0 THEN
CalculatedMonthsElapsed = 12 + CalculatedMonthsElapsed
END
END
IF CalculatedYearsElapsed = 1 Then
YearsToReturn = CalculatedYearsElapsed:' Year'
END ELSE
YearsToReturn = CalculatedYearsElapsed:' Years'
END
IF CalculatedMonthsElapsed = 1 THEN
MonthsToReturn = CalculatedMonthsElapsed:' Month'
END ELSE
MonthsToReturn = CalculatedMonthsElapsed:' Months'
END
ElapsedPeriod = YearsToReturn:' ':MonthsToReturn
END
RETURN

------------------------------
Sean Hannam
Payroll Architect
The Access Group
CHESTERFIELD United Kingdom
------------------------------

---

Seems so simple but, i'm trying to get ones exact age, on any given day, using their internal birthday. If I do the obvious, subtract internal birthdate from current date and divide by 36525, I get the accurate year but months and days comes out as a fraction of a year...

Anyone have an easy calc for this?

Thanks

------------------------------
Kathleen Hambrick
PROGRAMMER
William C Earhart Co Inc
Portland OR United States
------------------------------

Hi Kathleen,

This raises some questions for me:

02/01/1968 - 03/01/1968 = 0 years, 1 month, 0 days (seems obvious)
but then there's this:
02/29/1968 - 03/31/1968 = 0 years, 1 month, 0 days OR 0 years, 1 month, 2 days?

02/01/1967 - 02/01/1968 = 1 year, 0 months, 0 days (again, seems obvious)
but then there's:
02/28/1967 - 02/29/1968 = 1 year, 0 months, 0 days OR 1 year, 0 months, 1 day?
02/29/1968 - 02/28/1969 = 1 year, 0 months, 0 days OR 0 years, 11 months, 28 days?

If you think, "I won't worry about this, I'll only look at whole years and whole months and then gather up the stray days," in other words: days from the start date to the end of that month + whole years and whole months + days from the first of the end month to the end date.  But doing that can lead to more days than any given month could have:
02/10/1967 - 03/20/1969 = 18 days + 2 years and 0 months + 20 days ... or 2 years and 38 days!

In the above example, you might say "I'll just go from 10th to 10th to 10th, and then pick up any days left over!" In other words go from 02/10 to 03/10 to 04/10 to etc, to get 2 years, 1 month and 10 days.
What if we reverse the DDs: 02/20/1967 - 03/10/1969 = 2/20 to 3/20 to 4/20 to etc = 2 years and 18 days. That seems reasonable.
What about 01/30/1967 - 02/28/1969? 1/30/67 - 2/28/67 - 3/30/67 - ... - 1/30/69 - 2/28/69, so 2 years and 1 month? (The question is the day from 1/30/1967 to 1/31/1967, but it seems reasonable to leave it out.)
What about 01/28/1967 - 02/29/1968? 1 year, 1 month, 1 day? I guess that seems reasonable.
What about the above examples where the start date is the end of the month? I think that's a special case where you have to go from end of month to end of month, not exact dates. (We already kind of did that for Jan 30th to Feb 28th, etc. I'm just suggesting that if you start at the end of February then you go to the end of each other month before gathering up the stray days.)

So if you don't have a problem with 1/30/1967 - 2/28/1969 being 2 years and 1 month, then that seems like the way to go. If you do have a problem with it, then there will always potentially be wonkiness with start dates 29th, 30th or 31st.

Assuming you can live with that, this is a quick stab at an algorithm. It could definitely be made more efficient.

      PROGRAM DIFF.DATE
*
      D1 = '2/1/1968'
      D2 = '3/1/1968'
      GOSUB CALC.IT
*
      D1 = '2/29/1968'
      D2 = '3/31/1968'
      GOSUB CALC.IT
*
      D1 = '2/1/1967'
      D2 = '2/1/1968'
      GOSUB CALC.IT
*
      D1 = '2/28/1967'
      D2 = '2/29/1968'
      GOSUB CALC.IT
*
      D1 = '2/29/1968'
      D2 = '2/28/1969'
      GOSUB CALC.IT
*
      D1 = '2/10/1967'
      D2 = '3/20/1969'
      GOSUB CALC.IT
*
      D1 = '1/30/1967'
      D2 = '2/28/1969'
      GOSUB CALC.IT
*
      D1 = '2/12/1967'
      D2 = '10/18/1968'
      GOSUB CALC.IT
*
      D1 = '8/26/1967'
      D2 = '9/27/2021'
      GOSUB CALC.IT
*
      D1 = '10/28/1967'
      D2 = '9/27/2021'
      GOSUB CALC.IT
BOTTOM:
      STOP

CALC.IT:
      D1I = ICONV(D1,'D')
      D2I = ICONV(D2,'D')
*
      IF D2I <= D1I THEN
         YDIFF = 0
         MDIFF = 0
         DDIFF = 0
         GOTO EXIT.CALC.IT
      END
*
      PRINT OCONV(D1I,'D4/'):" - ":OCONV(D2I,'D4/')
*
      * are we starting on the last day of the month?
      IF (OCONV(D1I,'D M[2]') # OCONV(D1I+1,'D M[2]')) THEN
         * yes! advance both dates by 1 day
         D1I += 1
         D2I += 1
      END
*
      D1O = OCONV(D1I,'D4/')
      D2O = OCONV(D2I,'D4/')
      MM1 = D1O['/',1,1]; MM2 = D2O['/',1,1]
      DD1 = D1O['/',2,1]
      YYYY1 = D1O['/',3,1]; YYYY2 = D2O['/',3,1]
*
      IF YYYY1 < YYYY2 THEN
         YYYY3 = YYYY1
         LOOP
            DD3 = DD1
Y.TRY.AGAIN:
            D3I = ICONV(MM1:'/':DD3:'/':(YYYY3 + 1),'D')
            IF STATUS() THEN
               DD3 -= 1
               GOTO Y.TRY.AGAIN
            END
            TEST = D2I - D3I
         WHILE TEST >= 0 DO
            YYYY3 += 1
         REPEAT
      END ELSE
         YYYY3 = YYYY1
      END
      YDIFF = YYYY3 - YYYY1
*
      IF YYYY3 < YYYY2 OR MM1 < MM2 THEN
         MDIFF = 0
         MM3 = MM1; TEMP = DD1
         LOOP
            DD3 = DD1
M.TRY.AGAIN:
            IF MM3 = 12 THEN
               D3O = '01/':DD3:'/':(YYYY3 + 1)
            END ELSE
               D3O = (MM3 + 1):'/':DD3:'/':YYYY3
            END
            D3I = ICONV(D3O,'D')
            IF STATUS() THEN
               DD3 -= 1
               GOTO M.TRY.AGAIN
            END
            TEST = D2I - D3I
         WHILE TEST >= 0 DO
            MM3 = D3O['/',1,1]
            TEMP = D3O['/',2,1]
            YYYY3 = D3O['/',3,1]
            MDIFF += 1
         REPEAT
         DD3 = TEMP
      END ELSE
         DD3 = DD1
         MM3 = MM1
         MDIFF = 0
      END
*
      DDIFF = 0
      D3I = ICONV(MM3:'/':DD3:'/':YYYY3,'D')
      DDIFF = D2I - D3I
*
EXIT.CALC.IT:
      PRINT "YDIFF = ":YDIFF
      PRINT "MDIFF = ":MDIFF
      PRINT "DDIFF = ":DDIFF
      PRINT " "
      RETURN
*
   END
​

If that works for you, feel free to carve out the "CALC.IT" part and work it into a subroutine.

Thanks,

------------------------------
Tyrel Marak
Technical Support Manager
Aptron Corporation
Florham Park NJ United States
------------------------------

---

Seems so simple but, i'm trying to get ones exact age, on any given day, using their internal birthday. If I do the obvious, subtract internal birthdate from current date and divide by 36525, I get the accurate year but months and days comes out as a fraction of a year...

Anyone have an easy calc for this?

Thanks

------------------------------
Kathleen Hambrick
PROGRAMMER
William C Earhart Co Inc
Portland OR United States
------------------------------

Hi Kathleen,

Well your conundrum got me thinking while i was having a coffee and I thought perhaps this simpler approach might work for you, which i am sure you can hack to your own needs.....

PRINT @(-1):@(10,10):"ENTER DATE ": ; INPUT START.DATE
TODAY = DATE()
BDATE = ICONV(START.DATE,"D2/")
DAYS = (TODAY - BDATE)
BDAY.MONTH = FIELD(START.DATE,"/",2,1)
TODAY.MONTH = FIELD(OCONV(DATE(),"D2/"),"/",2,1)
IF BDATE LT "0" THEN
YEARS =INT((DAYS / 365.25))
END ELSE
IF BDAY.MONTH LT TODAY.MONTH THEN
YEARS =(INT((DAYS / 365.25)) - 1)
END ELSE
YEARS =(INT(DAYS / 365.25))
END
END
DYEAR = ((DAYS / 365.25) - (INT(DAYS /365)))
DDAYS = (DYEAR * 365.25)
MONTHS = INT(((DDAYS * 12)/365.25))
TODAY.DAY = OCONV(DATE(),"D2/")[1,2]
BDAY = START.DATE[1,2]
IF BDAY LT "0" THEN
BDAY = (BDAY * -1)
END
NO.DAYS = TODAY.DAY - BDAY
PRINT @(10,12):YEARS:" YEARS ":MONTHS:" MONTHS ":NO.DAYS: " DAYS"
END

I seems to work with pre 1967 dates

Thanks

Andy

------------------------------
Andrew Milne
Business Systems Manager
Potter and Moore Innovations
Peterborough, Cambs United Kingdom
------------------------------

---

Seems so simple but, i'm trying to get ones exact age, on any given day, using their internal birthday. If I do the obvious, subtract internal birthdate from current date and divide by 36525, I get the accurate year but months and days comes out as a fraction of a year...

Anyone have an easy calc for this?

Thanks

------------------------------
Kathleen Hambrick
PROGRAMMER
William C Earhart Co Inc
Portland OR United States
------------------------------

Kathleen,

It is difficult to calculate the age of someone based on the internal date. You need the year, month and day. See the function below. It determines the years of age (YOA) . I hope this helps.

FUNCTION YOA(BDAY,CDAY)
* BDAY IS THE BIRTHDATE IN INTERNAL FORMAT
* CDAY IS THE CHECK DATE IN INTERNAL FORMAT
YOA = 0 ;* YEAR OF AGE
OBDAY=OCONV(BDAY,"DYMD[4'',2'',2]") ;* YYYYMMDD
IF STATUS() THEN GOTO END.OF.FUNC:
OCDAY=OCONV(CDAY,"DYMD[4'',2'',2]") ;* YYYYMMDD
IF STATUS() THEN GOTO END.OF.FUNC:
IF CDAY LT BDAY THEN GOTO END.OF.FUNC:
YOA = OCDAY[1,4]-OBDAY[1,4]
IF OCDAY[5,2] LT OBDAY[5,2] THEN YOA -= 1
IF OCDAY[5,2] EQ OBDAY[5,2] AND OCDAY[2] LT OBDAY[2] THEN YOA -= 1
IF YOA LT 0 THEN YOA = 0
END.OF.FUNC:
RETURN(YOA)

------------------------------
Jon Kristofferson
Pick Programmer
Snap-on Credit LLC
Libertyville IL United States
------------------------------

---

Seems so simple but, i'm trying to get ones exact age, on any given day, using their internal birthday. If I do the obvious, subtract internal birthdate from current date and divide by 36525, I get the accurate year but months and days comes out as a fraction of a year...

Anyone have an easy calc for this?

Thanks

------------------------------
Kathleen Hambrick
PROGRAMMER
William C Earhart Co Inc
Portland OR United States
------------------------------

hi kathleen,
here is my used function :

FUNCTION DateDiff(begDate, endDate)
if num(begDate) else begDate = Iconv(begDate, 'D4/')
if num(endDate) else endDate = Iconv(endDate, 'D4/')
if begDate > endDate then x = begDate; begDate = endDate; endDate = x
begYear   = oconv(begDate, 'D4Y')
begMonth  = oconv(begDate, 'DM')
begDay    = oconv(begDate, 'DD')
begJulian = oconv(begDate, 'DJ')
endYear   = oconv(endDate, 'D4Y')
endMonth  = oconv(endDate, 'DM')
endDay    = oconv(endDate, 'DD')
endJulian = oconv(endDate, 'DJ')
diffYear  = endYear - begYear - (endJulian < begJulian) ;* bool = 1/0
diffMonth = (endMonth - begMonth) - (endDay < begDay) ;* bool = 1/0
if diffMonth < 0 then diffMonth += 12
diffDay   = endDay - begDay
if diffDay < 0 then diffDay += oconv(iconv('01/' : (if begMonth = 12 then 1 else begMonth + 1) : '/' : (begYear + (begMonth = 12)), 'd4/') - 1, 'DD') ;* first day of next month -1 , DD minus begDate 

RETURN (diffYear : @am : diffMonth : @am : diffDay)
​

usage 

DEFFUN DateDiff(startDate, stopDate, opt)

prompt ''
crt 'begin date' :;input d1
crt 'end   date' :;input d3
diff = DateDiff(d1,d2)
crt diff ;* <1> = year(s), <2> = month(s), <3> = day(s) 

I hope this can help 

------------------------------
Manu Fernandes
------------------------------

---

Seems so simple but, i'm trying to get ones exact age, on any given day, using their internal birthday. If I do the obvious, subtract internal birthdate from current date and divide by 36525, I get the accurate year but months and days comes out as a fraction of a year...

Anyone have an easy calc for this?

Thanks

------------------------------
Kathleen Hambrick
PROGRAMMER
William C Earhart Co Inc
Portland OR United States
------------------------------

Thanks all, I have what I need now.

------------------------------
Kathleen Hambrick
PROGRAMMER
William C Earhart Co Inc
Portland OR United States
------------------------------

---