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

Question

0.00/5 (No votes)

See more:

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

Add a Solution

3 solutions

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

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 :)

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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