Today I was given the task of finding the age of a person, provided the birth date. When I was given the task, I just said, just use the DateDiff function. But it is not that simple.
One thing I wanted was to keep the code simple and in a few lines of code. Here goes my first iteration.
static void CalculateAge()
{
DateTime dateOfBirth;
DateTime.TryParse("02/18/2008", out dateOfBirth);
DateTime currentDate = DateTime.Now;
TimeSpan difference = currentDate.Subtract(dateOfBirth);
// This is to convert the timespan to datetime object
DateTime age = DateTime.MinValue + difference;
// Min value is 01/01/0001
// Actual age is say 24 yrs, 9 months and 3 days represented as timespan
// Min Valye + actual age = 25 yrs , 10 months and 4 days.
// subtract our addition or 1 on all components to get the actual date.
int ageInYears = age.Year - 1;
int ageInMonths = age.Month - 1;
int ageInDays = age.Day - 1;
Console.WriteLine("{0}, {1}, {2}", ageInYears, ageInMonths, ageInDays);
}
But then, there were problems with this method. If the current date is ’06/18/2009′ and the birth date was ’04/18/2000′, it returns, 9 yrs, 2 months and 2 days. The 2 days part is wrong. I didn’t have any clue as to why it appears.
Then I went down to the basics, using elementary mathematics of subtraction. Here goes the second iteration of the code.
static void CalculateAge2()
{
DateTime dateOfBirth = new DateTime(2000, 6, 18);
int ageInYears = 0;
int ageInMonths = 0;
int ageInDays = 0;
CalculateAge(dateOfBirth, out ageInYears, out ageInMonths, out ageInDays);
Console.WriteLine("{0}, {1}, {2}", ageInYears, ageInMonths, ageInDays);
}
///
/// Calculate the Age of a person given the birthdate.
///
static void CalculateAge(DateTime adtDateOfBirth, out int aintNoOfYears, out int aintNoOfMonths, out int aintNoOfDays)
{
// get current date.
DateTime adtCurrentDate = DateTime.Now;
// find the literal difference
aintNoOfDays = adtCurrentDate.Day - adtDateOfBirth.Day;
aintNoOfMonths = adtCurrentDate.Month - adtDateOfBirth.Month;
aintNoOfYears = adtCurrentDate.Year - adtDateOfBirth.Year;
if (aintNoOfDays < 0)
{
aintNoOfDays += DateTime.DaysInMonth(adtCurrentDate.Year, adtCurrentDate.Month);
aintNoOfMonths--;
}
if (aintNoOfMonths < 0)
{
aintNoOfMonths += 12;
aintNoOfYears--;
}
}
And it works like a charm for all scenarios I throw upon it.
Scenario 1:
Current Date : 15 – 09 – 2009
Birth Date : 09 – 03 – 2000
Just a difference gives the result
Age : 6 – 6 – 9 Result is 9 yrs, 6 months, 6 days.
Scenario 2:
Current Date : 15 – 09 – 2009
Birth Date : 28 – 07 – 2000
Here since 15 – 28 < 0: we borrow one from the month and then add the no of days in the month to the current date. 15 + 30 = 45: 45 – 28 = 17 days
Then since one month is borrowed: 08 – 07 = 01 months
Remaining is normal difference
Age : 17 – 1 – 9 Result is 9 yrs, 1 months, 17 days.
Scenario 3:
Current Date : 15 – 09 – 2009
Birth Date : 28 – 12 – 2000
Here since 15 – 28 < 0: we borrow one from the month and then add the no of days in the current month to the current date. 15 + 30 = 45: 45 – 28 = 17 days
Then since one month is borrowed: 08 – 12: So we are supposed to borrow a year and add no of months in current year to current month. 08 + 12 = 20: 20 – 12 = 8 months
Since a year was borrowed: 2008 – 2000: 8 yrs
Remaining is normal difference
Age : 17 – 8 – 8 Result is 8 yrs, 8 months, 17 days.
But I know there must be better ways to do it. Feel free to drop in code snippets. Comments too are most welcome.
Raasukutty's 