Is there a better way to calculate age?

[Jamie Robertson]

requirements: input into method are 3 Strings representing the person's birth year, month and day ( YYYY, MM, DD ). Returns the person's age as an integer.
current method:

private int getAge(String year, String month, String day)
{
//set up date of birth
Calendar calDOB = Calendar.getInstance();
calDOB.set( Integer.parseInt(year), Integer.parseInt(month), Integer.parseInt(day) );
//setup calNow as today.
Calendar calNow = Calendar.getInstance();
calNow.setTime(new java.util.Date());
//calculate age in years.
int ageYr = (calNow.get(Calendar.YEAR) - calDOB.get(Calendar.YEAR));
// calculate additional age in months, possibly adjust years.
int ageMo = (calNow.get(Calendar.MONTH) - calDOB.get(Calendar.MONTH));
if (ageMo < 0)
{
//adjust years by subtracting one
ageYr--;
}
return ageYr;
}

it seems a little clunky to me. Someone out there must have a cleaner way.
Thanx,
Jamie

[SoonAnn Lim]

You may convert the birthday in second unit(note that before 1970 is negative value). Then get the current time using System.getCurrentTimeMillis() and change it to second by dividing 1000. Define number of second in a year which is 365*24*60*60. Then age should be (current_time-birthday)/second_year. Just a thought.

[Irene Loos]

Try this

  
Calendar dob = Calendar.getInstance();
dob.setTime(dateOfBirth);
Calendar today = Calendar.getInstance();
int age = today.get(Calendar.YEAR) - dob.get(Calendar.YEAR);
if (today.get(Calendar.DAY_OF_YEAR) < dob.get(Calendar.DAY_OF_YEAR))
age--;
return age;

[Ade Gray]

Correct, excellent, neat solution except that:-

Calendar dob = Calendar.getInstance();
dob.setTime(dateOfBirth);
Calendar today = Calendar.getInstance();
int age = today.get(Calendar.YEAR) - dob.get(Calendar.YEAR);
if (today.get(Calendar.DAY_OF_YEAR) < dob.get(Calendar.DAY_OF_YEAR))
age--;
return age;

should be

Calendar dob = Calendar.getInstance();
dob.setTime(dateOfBirth);
Calendar today = Calendar.getInstance();
int age = today.get(Calendar.YEAR) - dob.get(Calendar.YEAR);
if (today.get(Calendar.DAY_OF_YEAR) <= dob.get(Calendar.DAY_OF_YEAR))
age--;
return age;

Noting <= .

Try testing both versions for a birthday with tomorrow's date and you will see what I mean.
[ September 23, 2008: Message edited by: Ade Gray ]

[Henry Wong]

Please read this...

http://faq.javaranch.com/java/DontWakeTheZombies


Adding to a topic that is over 6 years old isn't very productive.

Henry

[Campbell Ritchie]

. . . but welcome to JavaRanch anyway

By the way, I think < was correct, not <=. There will be problems in leap years; 29th February 2008 returns the same DAY_OF_YEAR as 1st March 2007.