Objective-c: Calculate The Number Of Days Between Two Dates

diffDayBetweenTwoDates.m

NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"MM-dd-yyy"];
 
// To use a specific start date
//  NSDate *startDate = [formatter dateFromString:@"02-16-2013"];
 
// Start with todays date
NSDate *startDate = [NSDate date];
 
// End date
NSDate *endDate = [formatter dateFromString:@"12-28-2013"];
[formatter release];
 
NSCalendar *gregorianCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
 
// Notice the components:NSDayCalendarUnit specifier
NSDateComponents *components = [gregorianCalendar components:NSDayCalendarUnit
                                                    fromDate:startDate
                                                      toDate:endDate
                                                     options:0];
[gregorianCalendar release];
 
NSLog(@"Days between %@ and %@ is: %d", startDate, endDate, [components day]);