Diff between NSDates in seconds

gistfile1.txt

#import <Foundation/Foundation.h>

int main(int argc, char *argv[]) {
  @autoreleasepool {
	    unsigned int unitFlags = NSHourCalendarUnit | NSMinuteCalendarUnit | NSDayCalendarUnit | NSMonthCalendarUnit;
		
		NSDateFormatter *dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
		[dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];

		NSDate *date1 = [dateFormatter dateFromString:@"2013-06-28 00:00:00"];
		NSDate *date2 = [dateFormatter dateFromString:@"2013-06-29 00:00:00"];

		NSTimeInterval diff = [date2 timeIntervalSinceDate:date1];
		
		NSLog(@"%f", diff);
	}
}