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How would you calculate age in C # using date of birth (given leap years)

Here is the problem. I have seen many solutions, but no one seems to fulfill the criteria that I want ...

I want to show age in this format

20 y(s) 2 m(s) 20 d(s)
20 y(s) 2 m(s)
2 m(s) 20 d(s)
20 d(s)

etc...

I tried several solutions, but a leap year causes me a problem. My unit tests always fail due to leap years, and no matter how many days go between them, the leap will grant the number of extra days.

Here is my code ....

public static string AgeDiscription(DateTime dateOfBirth)
{
    var today = DateTime.Now;
    var days = GetNumberofDaysUptoNow(dateOfBirth);
    var months = 0;
    var years = 0;
    if (days > 365)
    {
        years = today.Year - dateOfBirth.Year;
        days = days % 365;
    }
    if (days > DateTime.DaysInMonth(today.Year, today.Month))
    {
        months = Math.Abs(today.Month - dateOfBirth.Month);
        for (int i = 0; i < months; i++)
        {
            days -= DateTime.DaysInMonth(today.Year, today.AddMonths(0 - i).Month);
        }
    }

    var ageDescription = new StringBuilder("");

    if (years != 0)
        ageDescription = ageDescription.Append(years + " y(s) ");
    if (months != 0)
        ageDescription = ageDescription.Append(months + " m(s) ");
    if (days != 0)
        ageDescription = ageDescription.Append(days + " d(s) ");

    return ageDescription.ToString();
}

public static int GetNumberofDaysUptoNow(DateTime dateOfBirth)
{
    var today = DateTime.Now;
    var timeSpan = today - dateOfBirth;
    var nDays = timeSpan.Days;
    return nDays;
}

Any ideas ???

UPDATE:

I want the difference between two dates like:

var dateOfBirth = DateTime.Now.AddYears(-20);
string expected = "20 y(s) ";
string actual; // returns 20 y(s) 5 d(s)
actual = Globals.AgeDiscription(dateOfBirth);
Assert.AreEqual(expected, actual);
+3
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6 answers

The age is quite complicated. Here are the relevant excerpts from the structure I'm using.

public struct Age
{
    private readonly Int32 _years;
    private readonly Int32 _months;
    private readonly Int32 _days;
    private readonly Int32 _totalDays;

    /// <summary>
    /// Initializes a new instance of <see cref="Age"/>.
    /// </summary>
    /// <param name="start">The date and time when the age started.</param>
    /// <param name="end">The date and time when the age ended.</param>
    /// <remarks>This </remarks>
    public Age(DateTime start, DateTime end)
        : this(start, end, CultureInfo.CurrentCulture.Calendar)
    {
    }

    /// <summary>
    /// Initializes a new instance of <see cref="Age"/>.
    /// </summary>
    /// <param name="start">The date and time when the age started.</param>
    /// <param name="end">The date and time when the age ended.</param>
    /// <param name="calendar">Calendar used to calculate age.</param>
    public Age(DateTime start, DateTime end, Calendar calendar)
    {
        if (start > end) throw new ArgumentException("The starting date cannot be later than the end date.");

        var startDate = start.Date;
        var endDate = end.Date;

        _years = _months = _days = 0;
        _days += calendar.GetDayOfMonth(endDate) - calendar.GetDayOfMonth(startDate);
        if (_days < 0)
        {
            _days += calendar.GetDaysInMonth(calendar.GetYear(startDate), calendar.GetMonth(startDate));
            _months--;
        }
        _months += calendar.GetMonth(endDate) - calendar.GetMonth(startDate);
        if (_months < 0)
        {
            _months += calendar.GetMonthsInYear(calendar.GetYear(startDate));
            _years--;
        }
        _years += calendar.GetYear(endDate) - calendar.GetYear(startDate);

        var ts = endDate.Subtract(startDate);
        _totalDays = (Int32)ts.TotalDays;
    }

    /// <summary>
    /// Gets the number of whole years something has aged.
    /// </summary>
    public Int32 Years
    {
        get { return _years; }
    }

    /// <summary>
    /// Gets the number of whole months something has aged past the value of <see cref="Years"/>.
    /// </summary>
    public Int32 Months
    {
        get { return _months; }
    }

    /// <summary>
    /// Gets the age as an expression of whole months.
    /// </summary>
    public Int32 TotalMonths
    {
        get { return _years * 12 + _months; }
    }

    /// <summary>
    /// Gets the number of whole weeks something has aged past the value of <see cref="Years"/> and <see cref="Months"/>.
    /// </summary>
    public Int32 Days
    {
        get { return _days; }
    }

    /// <summary>
    /// Gets the total number of days that have elapsed since the start and end dates.
    /// </summary>
    public Int32 TotalDays
    {
        get { return _totalDays; }
    }

    /// <summary>
    /// Gets the number of whole weeks something has aged past the value of <see cref="Years"/> and <see cref="Months"/>.
    /// </summary>
    public Int32 Weeks
    {
        get { return (Int32) Math.Floor((Decimal) _days/7); }
    }

    /// <summary>
    /// Gets the age as an expression of whole weeks.
    /// </summary>
    public Int32 TotalWeeks
    {
        get { return (Int32) Math.Floor((Decimal) _totalDays/7); }
    }
}

Here is an example unit test that passes:

    [Test]
    public void Should_be_exactly_20_years_old()
    {
        var now = DateTime.Now;
        var age = new Age(now.AddYears(-20), now);

        Assert.That(age, Has.Property("Years").EqualTo(20)
            .And.Property("Months").EqualTo(0)
            .And.Property("Days").EqualTo(0));
    }
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Timespan interval = DateTime.Now - DateOfBirth;


interval.Days
interval.TotalDays;
interval.Hours;
interval.TotalHours;
interval.Minutes;
interval.TotalMinutes;
interval.Seconds;
interval.TotalSeconds;
interval.Milliseconds;
interval.TotalMilliseconds;
interval.Ticks;

.

+2
static int AgeInYears(DateTime birthday, DateTime today)
{
    return ((today.Year - birthday.Year) * 372 + (today.Month - birthday.Month) * 31 + (today.Day - birthday.Day)) / 372;
}
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write this little function to have the number of days of a leap year between the current year and the date of the year of birth and add the returned days to part of your age:

 private static int NumberOfLeapYears(int startYear, int endYear)
 {         
 int counter = 0;
 for (int year = startYear; year <= endYear; year++)
 counter += DateTime.IsLeapYear(year) ? 1 : 0;
 return counter;
 }
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Check this code:

{                                                    
    dif = int(datediff("D", Convert.ToDateTime("01/" + Q101m.text + "/" + Q101y.Text), (Convert.ToDateTime(Vdate.text)))/365.25)

    //If dif < 15 Or dif > 49 
    {
           MessageBox.Show("xxxxxxx");
           Q101m.Focus();
    }

}
0
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I created the solution as an extension method in the DateTime class, which is "inherited" from @HackedByChinese:

    /// <summary>
    /// Calculate age in years relative to months and days, for example Peters age is 25 years 2 months and 10 days
    /// </summary>
    /// <param name="startDate">The date when the age started</param>
    /// <param name="endDate">The date when the age ended</param>
    /// <param name="calendar">Calendar used to calculate age</param>
    /// <param name="years">Return number of years, with considering months and days</param>
    /// <param name="months">Return calculated months</param>
    /// <param name="days">Return calculated days</param>
    public static bool GetAge(this DateTime startDate, DateTime endDate, Calendar calendar, out int years, out int months, out int days)
    {
        if (startDate > endDate)
        {
            years = months = days = -1;
            return false;
        }

        years = months = days = 0;
        days += calendar.GetDayOfMonth(endDate) - calendar.GetDayOfMonth(startDate);

        // When negative select days of last month
        if (days < 0)
        {
            days += calendar.GetDaysInMonth(calendar.GetYear(startDate), calendar.GetMonth(startDate));
            months--;
        }

        months += calendar.GetMonth(endDate) - calendar.GetMonth(startDate);

        // when negative select month of last year
        if (months < 0)
        {
            months += calendar.GetMonthsInYear(calendar.GetYear(startDate));
            years--;
        }

        years += calendar.GetYear(endDate) - calendar.GetYear(startDate);

        return true;
    }

But I realized that the results of the days may be slightly different from other calculators.

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