iOS - Comparing NSDate with another NSDate

Question

i know how to get difference between two NSDate as follow

NSTimeInterval timeInterval = [[NSDate date] timeIntervalSinceDate:anyPreviousDate];

and i know it will return me NSTimeInterval in positive seconds. what I want to know is what it will return if my anyPreviousDate is greater than [NSDate date] i.e. anyPreviousDate has not been passed it will come in future.

just curious if anybody has done that before.

Thanks in advance.

Answer 1

I have found another very nice approach to do the same... here is the code, i thought to share it with stackoverflow. Cocoa has couple of methods for this:

in NSDate

– isEqualToDate:  
– earlierDate:  
– laterDate:  
– compare:

When you use - (NSComparisonResult)compare:(NSDate *)anotherDate ,you get back one of these:

The receiver and anotherDate are exactly equal to each other, NSOrderedSame
The receiver is later in time than anotherDate, NSOrderedDescending
The receiver is earlier in time than anotherDate, NSOrderedAscending.

example:

NSDate * now = [NSDate date];
NSDate * mile = [[NSDate alloc] initWithString:@"2001-03-24 10:45:32 +0600"];
NSComparisonResult result = [now compare:mile];

NSLog(@"%@", now);
NSLog(@"%@", mile);

switch (result)
{
    case NSOrderedAscending: NSLog(@"%@ is in future from %@", mile, now); break;
    case NSOrderedDescending: NSLog(@"%@ is in past from %@", mile, now); break;
    case NSOrderedSame: NSLog(@"%@ is the same as %@", mile, now); break;
    default: NSLog(@"erorr dates %@, %@", mile, now); break;
}

[mile release];