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Age calculation

Hi,
I have a method that calculates a person's current age in years (which I now have rewritten). Now I'd like to calculate the age in years, months and days as well.
On the web I found a Javascript method that did this, but I found that it didn't calculate correctly every time.
The code looks like this after I've ported it to Delphi:

procedure CalculateAge(var nYears, nMonths, nDays: Integer; const dtBirthday, dtToday: TDateTime);
var
yyBd, mmBd, ddBd, yyTd, mmTd, ddTd: Word;
nY, nM, nD: Integer;
begin
DecodeDate(dtToday, yyTd, mmTd, ddTd);
DecodeDate(dtBirthday, yyBd, mmBd, ddBd);

nY := yyTd - yyBd;

if (mmTd >= mmBd) then
nM := mmTd - mmBd
else
begin
Dec(nY);
nM := 12 + mmTd - mmBd;
end;

if (ddTd >= ddBd) then
nD := ddTd - ddBd
else
begin
Dec(nM);
nD := 31 + ddTd - ddBd;

if (nM < 0) then
begin
nM := 11;
Dec(nY);
end;
end;
nYears := nY;
nMonths := nM;
nDays := nD;
end;

Could someone please tell me what is wrong with the code snipet above? Does anyone have a better solution? I'm completely stuck. I've tried almost everything.

Hope someone could help me...

-Jorgen
0
jorged
1 Solution

Commented:
I don't know Delphi, but here is a simple answer that you can use. Basically the first thing I do is convert the birthday and the current date  in to days, and subtract the two. From that value you get all your answers. This doesn't take into account leap years. You could easily include this by either dividing by 365.25 (approximate answer) or by determining the number of leap days between now and then adding it to the total (tYear-days % 4 (modulos))

class AgeCalculator {
public final static int[] DAYSINMONTH = {12,28,31,30,31,30,31,31,30,31,30,31};

public static void main(String[] args){
CalculateAge(21, 5, 75, 20, 3, 100);
}

public static void CalculateAge(int day, int month, int year, int tDay, int tMonth, int tYear){
int then = year*365;
for(int i = 0; i<month; i++) then += DAYSINMONTH[i];
then += day;

int today = tYear*365;
for(int i = 0; i<tMonth; i++) today += DAYSINMONTH[i];
today += tDay;

double daysOld = today - then;
double monthsOld = daysOld/12;
double yearsOld = daysOld/365;
System.out.println("Days Old = " + daysOld);
System.out.println("Months Old = " + monthsOld);
System.out.println("Years Old = " + yearsOld);

}

}
0

Author Commented:
Thank you,
I ported your code to Delphi and it works fine, but the code I've written myself while you wrote me this code, looks like it's a similar solution.

I also seem to have posted this question on the wrong forum, so this won't happen again. Sorry.

-Jorgen
0
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