Calculating Age In Java From Birth Date
Kushal Paudyal February 11th, 2010
Playing around with dates is tricky and can sometimes make you use your head, specially with the boundary conditions. In this tutorial, I am presenting a code that can take any birth date as the input and then calculates what is his / her age now.
Here is the algorithm:
- Subtract birth year from current year.
- Check if birth month is greater than current month (condition 1)
- If birth month is same, check if birth day of the month is latter than the current day of the month (condition 2)
- If condition 1 or condition 2 is satisfied, subtract 1 year from the difference calculated in step 1.
- This value is the correct age of the individual.
Having said that, here is the Java implementation of this algorithm.
package com.kushal.utils.date;
/**
* @Author Kushal Paudyal
* www.sanjaal.com/java
* Last Modified On 2009-10-13
*
* Takes any birth date as input
* Calculates the current age
*/
import java.util.GregorianCalendar;
import java.util.Calendar;
public class AgeCalculation {
/**
* Month Representations
*/
static final int JAN = 0;
static final int FEB = 1;
static final int MAR = 2;
static final int APR = 3;
static final int MAY = 4;
static final int JUN = 5;
static final int JUL = 6;
static final int AUG = 7;
static final int SEP = 8;
static final int OCT = 9;
static final int NOV = 10;
static final int DEC = 11;
public static void main(String[] args) {
System.out.println("Born In 1982-JUL-11. Current Age: "
+ calculateMyAge(1982, JUL, 11));
System.out.println("Born In 1957-DEC-09. Current Age: "
+ calculateMyAge(1957, DEC, 9));
}
/**
*
* @param year --> Birth Year
* @param month --> Birth Month
* @param day --> Birth Day
* @return --> Calculated Age
*/
private static int calculateMyAge(int year, int month, int day) {
Calendar birthCal = new GregorianCalendar(year, month, day);
Calendar nowCal = new GregorianCalendar();
int age = nowCal.get(Calendar.YEAR) - birthCal.get(Calendar.YEAR);
boolean isMonthGreater = birthCal.get(Calendar.MONTH) >= nowCal
.get(Calendar.MONTH);
boolean isMonthSameButDayGreater = birthCal.get(Calendar.MONTH) == nowCal
.get(Calendar.MONTH)
&& birthCal.get(Calendar.DAY_OF_MONTH) > nowCal
.get(Calendar.DAY_OF_MONTH);
if (isMonthGreater || isMonthSameButDayGreater) {
age=age-1;
}
return age;
}
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*
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}
Here is the output of the program above:
Born In 1982-JUL-11. Current Age: 27 Born In 1957-DEC-09. Current Age: 51
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Originally posted 2009-10-13 10:18:55.
