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Check if the dates are more than 1 year apart [duplicate]

This question already has an answer here:
Timespan contains leapyear
(1 answer)
Closed 1 year ago.
I am trying to check if the total of two dates is more than 1 year or not. Below is the code that I am using but this code accepts 1 year. Which I find it wrong.
public bool CheckDate(DateTime Date1, DateTime Date2)
{
DateTime BaseTime = new DateTime(1, 1, 1);
TimeSpan span = Date2- Date1;
int years = (BaseTime + span).Year - 1;
if (years >= 1)
return true;
else
return false;
}
Is there a way to make it count as days and considering leap years?

You can simply add a year and compare the value, like this.
public bool CheckDate(DateTime Date1, DateTime Date2)
{
return (Date2.AddYears(1) > Date1);
}

You can check out NodaTime for this kind of date calculations. Also, you can benefit from NodaTime's period feature (that will take care of leap years as well) to find a period between two dates. Folowing is an example similar to your function that you can have a look at and you can read further about date time arithmetics here.
private static bool CheckDate(DateTime date1, DateTime date2)
{
var localDate1 = new LocalDate(date1.Year, date1.Month, date1.Day);
var localDate2 = new LocalDate(date2.Year, date2.Month, date2.Day);
var period = Period.Between(localDate1, localDate2, PeriodUnits.Days | PeriodUnits.Years);
Console.WriteLine("Years: {0} & Days: {1}", period.Years, period.Days);
if (period.Years >= 1)
{
return true;
}
return false;
}

Will this be a good answer?
public bool CheckDate(DateTime Date1, DateTime Date2)
{
double Days = (Date2- Date1).TotalDays;
if (Days > 365)
return true;
else
return false;
}

How to do I invert the week returned from Calendar.GetWeekOfYear back to a DateTime? [duplicate]

This question already has answers here:
Calculate date from week number
(26 answers)
Closed 9 years ago.
The problem is there does not seem to be a built-in way to get a DateTime from a previously calculated "week number".
What I want to do is basically have this work for all times and all cultural calendars.
DateTime dt1 = new DateTime.Now;
int week = cal.GetWeekOfYear(dt);
DateTime dt2 = GetDateTimeFromYearAndWeek(dt.Year, week);
if (dt1 < dt2 || dt2 > dt2.AddDays(7.0))
{
throw new Exception("new datetime limits do not span existing datetime;
}
I think one of the issues is that for some cultures, the cal.GetWeekOfYear(dt) call will return the correct week number for a different year from dt.Year. That means you can't use it in the call to my fictious GetDateTimeFromYearAndWeek call.

My own answer is three-fold. First, I came up with a wrapper to Calendar.GetWeekOfYear that returns the "year" of the week, since this year may not be the same as the year of the DateTime object.
public static void GetWeek(DateTime dt, CultureInfo ci, out int week, out int year)
{
year = dt.Year;
week = ci.Calendar.GetWeekOfYear(dt, ci.DateTimeFormat.CalendarWeekRule, ci.DateTimeFormat.FirstDayOfWeek);
int prevweek = ci.Calendar.GetWeekOfYear(dt.AddDays(-7.0), ci.DateTimeFormat.CalendarWeekRule, ci.DateTimeFormat.FirstDayOfWeek);
if (prevweek + 1 == week) {
// year of prevweek should be correct
year = dt.AddDays(-7.0).Year;
} else {
// stay here
year = dt.Year;
}
}
Next, here is the meat of the answer. This inverts the year and weekOfYear back into a DateTime object. Note that I used the middle of the year, because this seems to avoid the problems with the singularities of the new year (where 52 or 53 may or not wrap around to 1). I also synchronize the date by finding a date that is indeed the first day of the week, avoiding problems with negative offsets comparing two DayOfWeek values.
public static DateTime FirstDateOfWeek(int year, int weekOfYear, CultureInfo ci)
{
DateTime jul1 = new DateTime(year, 7, 1);
while (jul1.DayOfWeek != ci.DateTimeFormat.FirstDayOfWeek)
{
jul1 = jul1.AddDays(1.0);
}
int refWeek = ci.Calendar.GetWeekOfYear(jul1, ci.DateTimeFormat.CalendarWeekRule, ci.DateTimeFormat.FirstDayOfWeek);
int weekOffset = weekOfYear - refWeek;
return jul1.AddDays(7 * weekOffset );
}
And finally to all those who doubt it, here is my unit test that cycles through lots of dates and cultures to make sure it works on all of them.
public static void TestDates()
{
foreach (CultureInfo ci in CultureInfo.GetCultures(CultureTypes.AllCultures).Where((x)=>!x.IsNeutralCulture && x.Calendar.AlgorithmType == CalendarAlgorithmType.SolarCalendar))
{
for (int year = 2010; year < 2040; year++)
{
// first try a bunch of hours in this year
// convert from date -> week -> date
for (int hour = 0; hour < 356 * 24; hour+= 6)
{
DateTime dt = new DateTime(year, 1, 1).AddHours(hour);
int ww;
int wyear;
Gener8.SerialNumber.GetWeek(dt, ci, out ww, out wyear);
if (wyear != year)
{
//Console.WriteLine("{0} warning: {1} {2} {3}", ci.Name, dt, year, wyear);
}
DateTime dt1 = Gener8.SerialNumber.FirstDateOfWeek(wyear, ww, ci);
DateTime dt2 = Gener8.SerialNumber.FirstDateOfWeek(wyear, ww, ci).AddDays(7.0);
if (dt < dt1 || dt > dt2)
{
Console.WriteLine("{3} Bad date {0} not between {1} and {2}", dt, dt1, dt2, ci.Name);
}
}
// next try a bunch of weeks in this year
// convert from week -> date -> week
for (int week = 1; week < 54; week++)
{
DateTime dt0 = FirstDateOfWeek(year, week, ci);
int ww0;
int wyear0;
GetWeek(dt0, ci, out ww0, out wyear0);
DateTime dt1 = dt0.AddDays(6.9);
int ww1;
int wyear1;
GetWeek(dt1, ci, out ww1, out wyear1);
if ((dt0.Year == year && ww0 != week) ||
(dt1.Year == year && ww1 != week))
{
Console.WriteLine("{4} Bad date {0} ww0={1} ww1={2}, week={3}", dt0, ww0, ww1, week, ci.Name);
}
}
}
}
}

Calculate age from date in textbox in C# [duplicate]

This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Calculating age from birthday
How do you calculate age in years, taking input from TextBox in the format dd/MM/yyyy?
e.g.
input: txtDOB.Text 20/02/1989 (String format)
output: txtAge.Text 23

You can use the Substract method of DateTime (link) and then use the Days property to determine the actual age:
DateTime now = DateTime.Now;
DateTime givenDate = DateTime.Parse(input);
int days = now.Subtract(givenDate).Days
int age = Math.Floor(days / 365.24219)

TimeSpan TS = DateTime.Now - new DateTime(1989, 02, 20);
double Years = TS.TotalDays / 365.25; // 365 1/4 days per year

As already noted in a comment, the correct answer is here: Calculate age in C#
You just need to get the birthday as a DateTime:
DateTime bday = DateTime.ParseExact("20/02/1989", "dd/MM/yyyy", CultureInfo.InvariantCulture);

The following will work once you have parsed the birth date into a DateTime:
static int AgeInYears(DateTime birthday, DateTime today)
{
return ((today.Year - birthday.Year) * 372 + (today.Month - birthday.Month) * 31 + (today.Day - birthday.Day)) / 372;
}
Parse the date like so:
DateTime dob = DateTime.ParseExact("20/02/1989", "dd/MM/yyyy", CultureInfo.InvariantCulture);
And a sample program:
using System;
namespace Demo
{
class Program
{
static void Main(string[] args)
{
DateTime dob = new DateTime(2010, 12, 30);
DateTime today = DateTime.Now;
int age = AgeInYears(dob, today);
Console.WriteLine(age); // Prints "1"
}
static int AgeInYears(DateTime birthday, DateTime today)
{
return ((today.Year - birthday.Year) * 372 + (today.Month - birthday.Month) * 31 + (today.Day - birthday.Day)) / 372;
}
}
}

This answer isn't the most efficient as it uses a loop, but it doesn't rely on using 365.25 magic numbers either.
A function to return the whole number of years from a datetime to today:
public static int CalcYears(DateTime fromDate)
{
int years = 0;
DateTime toDate = DateTime.Now;
while (toDate.AddYears(-1) >= fromDate)
{
years++;
toDate = toDate.AddYears(-1);
}
return years;
}
Usage:
int age = CalcYears(DateTime.ParseExact(txtDateOfBirth.Text, "dd/MM/yyyy", CultureInfo.InvariantCulture));

var date = DateTime.ParseExact("20/02/1989", "dd/MM/yyyy", System.Globalization.CultureInfo.InvariantCulture);
var age = (DateTime.Today.Year - date.Year);
Console.WriteLine(age);

Try this
string[] AgeVal=textbox.text.split('/');
string Year=AgeVal[2].tostring();
string CurrentYear= DateTime.Now.Date.Year.ToString();
int Age=Convert.ToInt16((Current))-Convert.ToInt16((Year));
Subtract the two values and get your age.

How to calculate the number of years between 2 dates?

I would like to compare 2 dates to confirm that the number of years between is >= 18. For example, if my 2 dates are 03-12-2011 and 03-12-1983 then this should pass validation, however, if my 2 dates are 03-12-2011 and 03-12-1995 then this should fail validation.
Can anyone help me?

hope this is what you are looking for
public bool CheckDate(DateTime date1, DateTime date2)
{
return date1.AddYears(-18) < date2;
}

I re-jigged your question title & description to make it a bit more clear. From what I gathered from your original post you are looking for an Age Verification function. Here is what I would do:
function VerifyAge(DateTime dateOfBirth)
{
DateTime now = DateTime.Today;
int age = now.Year - dateOfBirth.Year;
if (now.Month < dateOfBirth.Month || (now.Month == dateOfBirth.Month && now.Day < dateOfBirth.Day))
age--;
return age >= 18;
}

Use TimeSpan structure.
TimeSpan span= dateSecond - dateFirst;
int days=span.Days;
//or
int years = (int) (span.Days / 365.25);

Check the TimeSpan structure:
http://msdn.microsoft.com/en-us/library/system.timespan.aspx

Use Timespan:
TimeSpan day = 03-12-2011 - 03-12-1983;
double year = day.TotalDays / 365.25;
if (year > 18)
{
}
Maybe instead of 03-12-2011 you should use DateTime.Now

Here's a method to check if the age is more than 18:
private bool IsMoreThan18(DateTime from, DateTime to)
{
int age = to.Year - from.Year;
if (from > to.AddYears(-age)) age--;
return age >= 18;
}

DateTime zeroTime = new DateTime(1, 1, 1);
DateTime a = new DateTime(2008, 1, 1);
DateTime b = new DateTime(2016, 1, 1);
TimeSpan span = b - a;
// because we start at year 1 for the Gregorian
// calendar, we must subtract a year here.
int years = (zeroTime + span).Year - 1;
Console.WriteLine("Years elapsed: " + years);
Refrence Link

Try this....
Using this you can get the exact no of years between two days. Only you need to do is divide the date difference by 365.25
TimeSpan span = DateTime.Parse(To_Date) - DateTime.Parse(From_Date);
int years = (int)(span.Days / 365.25);

Create two DateTime objects and substract them from eachother.
The result is a DateTime object aswel:
DateTime dt = new DateTime(2011, 12, 03);
DateTime dt2 = new DateTime(1983, 12, 03);
DateTime dt3 = dt - dt2;
Now you can check dt3.Year for the number of years between them

Date difference in years using C# [duplicate]

This question already has answers here:
How do I calculate someone's age based on a DateTime type birthday?
(74 answers)
Closed 6 years ago.
How can I calculate date difference between two dates in years?
For example: (Datetime.Now.Today() - 11/03/2007) in years.

I have written an implementation that properly works with dates exactly one year apart.
However, it does not gracefully handle negative timespans, unlike the other algorithm. It also doesn't use its own date arithmetic, instead relying upon the standard library for that.
So without further ado, here is the code:
DateTime zeroTime = new DateTime(1, 1, 1);
DateTime a = new DateTime(2007, 1, 1);
DateTime b = new DateTime(2008, 1, 1);
TimeSpan span = b - a;
// Because we start at year 1 for the Gregorian
// calendar, we must subtract a year here.
int years = (zeroTime + span).Year - 1;
// 1, where my other algorithm resulted in 0.
Console.WriteLine("Yrs elapsed: " + years);

Use:
int Years(DateTime start, DateTime end)
{
return (end.Year - start.Year - 1) +
(((end.Month > start.Month) ||
((end.Month == start.Month) && (end.Day >= start.Day))) ? 1 : 0);
}

We had to code a check to establish if the difference between two dates, a start and end date was greater than 2 years.
Thanks to the tips above it was done as follows:
DateTime StartDate = Convert.ToDateTime("01/01/2012");
DateTime EndDate = Convert.ToDateTime("01/01/2014");
DateTime TwoYears = StartDate.AddYears(2);
if EndDate > TwoYears .....

If you need it for knowing someone's age for trivial reasons then Timespan is OK but if you need for calculating superannuation, long term deposits or anything else for financial, scientific or legal purposes then I'm afraid Timespan won't be accurate enough because Timespan assumes that every year has the same number of days, same # of hours and same # of seconds).
In reality the length of some years will vary (for different reasons that are outside the scope of this answer). To get around Timespan's limitation then you can mimic what Excel does which is:
public int GetDifferenceInYears(DateTime startDate, DateTime endDate)
{
//Excel documentation says "COMPLETE calendar years in between dates"
int years = endDate.Year - startDate.Year;
if (startDate.Month == endDate.Month &&// if the start month and the end month are the same
endDate.Day < startDate.Day// AND the end day is less than the start day
|| endDate.Month < startDate.Month)// OR if the end month is less than the start month
{
years--;
}
return years;
}

var totalYears =
(DateTime.Today - new DateTime(2007, 03, 11)).TotalDays
/ 365.2425;
Average days from Wikipedia/Leap_year.

int Age = new DateTime((DateTime.Now - BirthDateTime).Ticks).Year;
To calculate the elapsed years (age), the result will be minus one.
var timeSpan = DateTime.Now - birthDateTime;
int age = new DateTime(timeSpan.Ticks).Year - 1;

Here is a neat trick which lets the system deal with leap years automagically. It gives an accurate answer for all date combinations.
DateTime dt1 = new DateTime(1987, 9, 23, 13, 12, 12, 0);
DateTime dt2 = new DateTime(2007, 6, 15, 16, 25, 46, 0);
DateTime tmp = dt1;
int years = -1;
while (tmp < dt2)
{
years++;
tmp = tmp.AddYears(1);
}
Console.WriteLine("{0}", years);

It's unclear how you want to handle fractional years, but perhaps like this:
DateTime now = DateTime.Now;
DateTime origin = new DateTime(2007, 11, 3);
int calendar_years = now.Year - origin.Year;
int whole_years = calendar_years - ((now.AddYears(-calendar_years) >= origin)? 0: 1);
int another_method = calendar_years - ((now.Month - origin.Month) * 32 >= origin.Day - now.Day)? 0: 1);

I implemented an extension method to get the number of years between two dates, rounded by whole months.
/// <summary>
/// Gets the total number of years between two dates, rounded to whole months.
/// Examples:
/// 2011-12-14, 2012-12-15 returns 1.
/// 2011-12-14, 2012-12-14 returns 1.
/// 2011-12-14, 2012-12-13 returns 0,9167.
/// </summary>
/// <param name="start">
/// Stardate of time period
/// </param>
/// <param name="end">
/// Enddate of time period
/// </param>
/// <returns>
/// Total Years between the two days
/// </returns>
public static double DifferenceTotalYears(this DateTime start, DateTime end)
{
// Get difference in total months.
int months = ((end.Year - start.Year) * 12) + (end.Month - start.Month);
// substract 1 month if end month is not completed
if (end.Day < start.Day)
{
months--;
}
double totalyears = months / 12d;
return totalyears;
}

public string GetAgeText(DateTime birthDate)
{
const double ApproxDaysPerMonth = 30.4375;
const double ApproxDaysPerYear = 365.25;
int iDays = (DateTime.Now - birthDate).Days;
int iYear = (int)(iDays / ApproxDaysPerYear);
iDays -= (int)(iYear * ApproxDaysPerYear);
int iMonths = (int)(iDays / ApproxDaysPerMonth);
iDays -= (int)(iMonths * ApproxDaysPerMonth);
return string.Format("{0} år, {1} måneder, {2} dage", iYear, iMonths, iDays);
}

I found this at TimeSpan for years, months and days:
DateTime target_dob = THE_DOB;
DateTime true_age = DateTime.MinValue + ((TimeSpan)(DateTime.Now - target_dob )); // Minimum value as 1/1/1
int yr = true_age.Year - 1;

If you're dealing with months and years you need something that knows how many days each month has and which years are leap years.
Enter the Gregorian Calendar (and other culture-specific Calendar implementations).
While Calendar doesn't provide methods to directly calculate the difference between two points in time, it does have methods such as
DateTime AddWeeks(DateTime time, int weeks)
DateTime AddMonths(DateTime time, int months)
DateTime AddYears(DateTime time, int years)

DateTime musteriDogum = new DateTime(dogumYil, dogumAy, dogumGun);
int additionalDays = ((DateTime.Now.Year - dogumYil) / 4); //Count of the years with 366 days
int extraDays = additionalDays + ((DateTime.Now.Year % 4 == 0 || musteriDogum.Year % 4 == 0) ? 1 : 0); //We add 1 if this year or year inserted has 366 days
int yearsOld = ((DateTime.Now - musteriDogum).Days - extraDays ) / 365; // Now we extract these extra days from total days and we can divide to 365

Works perfect:
internal static int GetDifferenceInYears(DateTime startDate)
{
int finalResult = 0;
const int DaysInYear = 365;
DateTime endDate = DateTime.Now;
TimeSpan timeSpan = endDate - startDate;
if (timeSpan.TotalDays > 365)
{
finalResult = (int)Math.Round((timeSpan.TotalDays / DaysInYear), MidpointRounding.ToEven);
}
return finalResult;
}

Simple solution:
public int getYearDiff(DateTime startDate, DateTime endDate){
int y = Year(endDate) - Year(startDate);
int startMonth = Month(startDate);
int endMonth = Month(endDate);
if (endMonth < startMonth)
return y - 1;
if (endMonth > startMonth)
return y;
return (Day(endDate) < Day(startDate) ? y - 1 : y);
}

This is the best code to calculate year and month difference:
DateTime firstDate = DateTime.Parse("1/31/2019");
DateTime secondDate = DateTime.Parse("2/1/2016");
int totalYears = firstDate.Year - secondDate.Year;
int totalMonths = 0;
if (firstDate.Month > secondDate.Month)
totalMonths = firstDate.Month - secondDate.Month;
else if (firstDate.Month < secondDate.Month)
{
totalYears -= 1;
int monthDifference = secondDate.Month - firstDate.Month;
totalMonths = 12 - monthDifference;
}
if ((firstDate.Day - secondDate.Day) == 30)
{
totalMonths += 1;
if (totalMonths % 12 == 0)
{
totalYears += 1;
totalMonths = 0;
}
}

Maybe this will be helpful for answering the question: Count of days in given year,
new DateTime(anyDate.Year, 12, 31).DayOfYear //will include leap years too
Regarding DateTime.DayOfYear Property.

The following is based off Dana's simple code which produces the correct answer in most cases. But it did not take in to account less than a year between dates. So here is the code that I use to produce consistent results:
public static int DateDiffYears(DateTime startDate, DateTime endDate)
{
var yr = endDate.Year - startDate.Year - 1 +
(endDate.Month >= startDate.Month && endDate.Day >= startDate.Day ? 1 : 0);
return yr < 0 ? 0 : yr;
}