Question

Possible Duplicate:
How can I calculate the difference between two dates?
NSDate, comparing two dates

I have got two dates. How to check if theres a difference of 30 days in between them?
I actually have an In-App purchase which needs to be disabled after every 30-days of purchase.
When the user buys the feature, the Date is saved and so I need to check the dates. If 30-days have passed, I need to disable the feature again.

Answer 1

You can convert both dates to seconds with timeIntervalSince1970 and then check if difference is bigger than 2592000 (30*24*60*60 which is 30 days * 24 hours * 60 minutes * 60 seconds).

NSTimeInterval difference = [date1 timeIntervalSince1970] - [date2 timeIntervalSince1970];

if(difference >2592000)
{
 //do your stuff here
}

EDIT:
For more compact version you can use – (NSTimeInterval)timeIntervalSinceDate:(NSDate *)anotherDate

NSTimeInterval difference = [date1 timeIntervalSinceDate:date2];
if(difference >2592000)
{
    //do your stuff here
}