How i campare two dates in Iphone?

I want to set date and time two days after my current date and time.How i set it using NSDate and dateformatter. I want compare date after two days, it was perviously set or not.

I write code now for it, NSCalendar *calendar = [NSCalendar autoupdatingCurrentCalendar];

NSDate *pickerDate = [self.datePicker date];

NSDateComponents *dateComponents = [calendar components:( NSYearCalendarUnit | NSMonthCalendarUnit |  NSDayCalendarUnit ) 
                                               fromDate:pickerDate];

NSDateComponents *timeComponents = [calendar components:( NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit ) 
                                               fromDate:pickerDate];

NSDateComponents *dateComps = [[NSDateComponents alloc] init];

[dateComps setDay:[dateComponents day]];
[dateComps setMonth:[dateComponents month]];
[dat开发者_如何学PythoneComps setYear:[dateComponents year]];
[dateComps setHour:[timeComponents hour]];
[dateComps setMinute:[timeComponents minute]];
[dateComps setSecond:00];

NSDate *itemDate = [calendar dateFromComponents:dateComps];
[dateComps release];
appDelegate.setTimerByUser = [itemDate retain];

How i compare it with current time and date? Thanks

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Look in NSDate.h and read Apple's docs for the -compare function on NSDates.

You can do for example:

NSDate  *now = [NSDate date];
NSDate  *future = [now dateByAddingTimeInterval: 2 * 24 * 60 * 60]; // add two days

if ( [now compare: future] == NSOrderedAscending ) {
    // now is earlier than future so we will always get here
} else {
    // never reached but illustrates how you might use compare
}

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I think you need NSDateComponents. You can use this class to get year, month, day, and other attributes about date and time.

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NSDate * now = [NSDate date];
NSDate * twoDaysFromNow = [now dateByAddingTimeInterval:(2 * 24* 60 * 60)];

You can compare with NSDate's -earlierDate: or -laterDate: methods.