.AddDays is a _function_ that returns the _new_ value, not a method
that changes the existing value. Thus when you do

d.AddDays(3);

you are saying: Take the value of d, add three days to it, then do
nothing with the result. The three days does get added to it; but the
result is then thrown away.

But when you say

d=DateTime.Now.AddDays(4);

you are saying: Take the value of DateTime.Now, add four days to it,
and _assign the resulting value to d_.

If you want to change d from its current value to (its current value
plus three days), you should say

d = d.AddDays(3);

Hi Madhur,

You have added 3 days to d, but you did not store the value to any variable.
So as intialized in the first step d has the present time alone.
Moreover you have used DateTime.Now(), Now is the property but it is used
like a method.

This might work correctly.
DateTime d = DateTime.Now;

d=d.AddDays(3);

Regards,

Valli.

www.syncfusion.com

Whenever something surprising happens, it's best to consult the
documentation. Here's part of what MSDN says about DateTime.AddDays in
the "Remarks" section:

<quote>
This method does not change the value of this DateTime. Instead, a new
DateTime is returned whose value is the result of this operation.
</quote>