Mailing List Archive: 49091 messages

## [REBOL] Re: How to...? Convert Date of Birth to Age

### From: al:bri:xtra at: 4-Jul-2002 16:58

```
Joel Neely wrote:
> Good questions, to which I'll add another:
>
>     If you were born on 29 Feb 2000, when did your next
>     birthday occur?
>
> Given the irregularities in the current calendar scheme, I guess I'd have
to wonder about the purpose of the calculation before forming opinions re
date arithmetic including/surrounding leap days.

Birthday parties usually occur on the same day and month each year as one's
birthdate. If one is born on a leap-year day, like:
>> leap-year? 29/Feb/2000
== true
then one has less birthdays than most other people. But, one can still
calculate one's age as that's just the number of years, months and days that
have elapsed since one's birth date.

>> now
== 4-Jul-2002/16:56:42+12:00
>> probe age now 29/Feb/2000

make object! [
Years: 2
Months: 4
Days: 5
]

Age: function [
"Calulates Age in Years, Months & Days."
Date1 [date!]
Date2 [date!]
] [Difference Years Months Days] [
if Date1 < Date2 [
Years: Date1
Date1: Date2
Date2: Years
]
Difference: Date1 - Date2
Years: Date1/year
Months: Date1/month
Days: subtract Date1/day Date2/day
if negative? Days [
Months: Months - 1
Days: Days + pick system/locale/days-per-month either 1 <= Months [
Months
] [
length? system/locale/days-per-month
]
if all [
2 = Months ; Previous month = February?
leap-year? Date1
] [
Days: Days + 1
]
]
Months: Months - Date2/month
if negative? Months [
Years: Years - 1
Months: Months + 12
]
Years: Years - Date2/year
make object! compose [Years: (Years) Months: (Months) Days: (Days)]
]

Andrew Martin
ICQ: 26227169 http://valley.150m.com/
```