C# - convert 'days old' to date of birth?

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Hi,

I need to convert how many 'days Old' someone is (e.g. 3 years old = 1,095 days old) to a 'date of birth' answer i.e. dd/MM/yyyy. I have tried many different ways how to do this, but to no avail (yet) - e.g. using a mathematical formula but it gets a bit complicated, especially when considering how to implement that into C# (for a beginner, at least).

What is in the box below is one of the many ways I have tried thus far. I know it's wrong but it's one of many of my attempts. What is the simplest way to go about this (assuming 1 year is 365 days, if the computer doesn't have it's own automated calculation to include leap years)?

Finally, if I am to include leap years, would the adjustment to simply be to take into consideration that 1 year = 365.25 years? Or would there be more complexity to this?

Kind regards.

What I have tried:

public static string GetBirthDate(int daysOld)
{
    var dateToday = Convert.ToInt32(DateTime.Now);

    var calc = (dateToday - 365.25 * daysOld);

    return Convert.ToString(calc);
}

Posted 14-Jul-17 2:56am

Member 13302374

Updated 14-Jul-17 3:24am

v2

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3 solutions

Solution 1

If I were doing something like this, I would do it like this:

C#

public static DateTime(int days)
{
  return new DateTime.Now.Subtract(TimeSpan.FromDays(days));
}

Posted 14-Jul-17 3:07am

Pete O'Hanlon

Comments

Richard Deeming 14-Jul-17 9:30am

You'll need a function name in there! :)

Pete O'Hanlon 14-Jul-17 10:05am

It's in there, but only if you can read subatomic :)

Solution 3

C#

public static string GetBirthDate(int daysOld)
{
    // DateTime.Now.AddDays(-daysOld).To... has many format options
    // beware AddDays: daysOld conversion to type double

    return DateTime.Now.AddDays(-daysOld).ToString("dd'/'MM'/'yyyy")
}

Posted 14-Jul-17 3:24am

User 7407470

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F-ES Sitecore · Accepted Answer · 2017-07-14T03:08:00

Solution 2

int daysOld = 1095;
DateTime dob = DateTime.Now.AddDays(daysOld * -1);

Posted 14-Jul-17 3:08am

F-ES Sitecore