NSDate / NSCalender count days in year - xcode

Question

I am making an app that calculates salaries based on the years somebody is working for a firm. The user enter 2 dates, the first one is the day he started working (let's say 1/12/2010) and the second is the end date (let's say 1/02/2012). So far i know the total days he worked but i want to be more specific in order to calculate that he worked:
30 days in 2010 * 30$ per day = 90$
365 days in 2011 * 35$ per day = 12775$
32 days in 2012 * 40$ per day = 1280$
It's the first time i am working with dates and calendars and as you can guess i am totally unfamiliar with them.

Answer 1

Try this code :
-(NSInteger)daysBetweenTwoDates:(NSDate *)fromDateTime andDate:(NSDate*)toDateTime{
NSDate *fromDate;
NSDate *toDate;
NSCalendar *calendar = [NSCalendar currentCalendar];
[calendar rangeOfUnit:NSDayCalendarUnit startDate:&fromDate interval:NULL forDate:fromDateTime];
[calendar rangeOfUnit:NSDayCalendarUnit startDate:&toDate interval:NULL forDate:toDateTime];
NSDateComponents *difference = [calendar components:NSDayCalendarUnit fromDate:fromDate toDate:toDate options:0];
return [difference day]+1;//+1 as if start and end both date are same, so 1 day worked.
}
- (IBAction)calculate:(id)sender {
NSDate *startDate=[self.startDate dateValue];//taking from datepicker
NSDate *endDate=[self.endDate dateValue];//taking from datepicker
NSTimeZone *gmt=[NSTimeZone timeZoneWithAbbreviation:#"GMT"];
NSDateFormatter *dateFormatterYYYY=[NSDateFormatter new];
[dateFormatterYYYY setTimeZone:gmt];
[dateFormatterYYYY setDateFormat:#"YYYY"];
NSDateFormatter *dateFormatterDDMMYYYY=[NSDateFormatter new];
[dateFormatterDDMMYYYY setDateFormat:#"dd/mm/YYYY"];
[dateFormatterDDMMYYYY setTimeZone:gmt];
//1. startDate to 31/12/StartDateYear
//2. loop to endDateYear
//3. 01/01/endDateYear to endDate
/* step 1 */
//find 31/12/StartDateYear
NSLog(#"YYYY ; %#",[dateFormatterYYYY stringFromDate:startDate]);
NSString *lastDateOfStartYearString=[NSString stringWithFormat:#"31/12/%#",[dateFormatterYYYY stringFromDate:startDate]];
NSDateFormatter *dateFormatddMMyyyy=[NSDateFormatter new];
[dateFormatddMMyyyy setDateFormat:#"dd'/'MM'/'yyyy"];
NSDate *lastDateOfStartYear=[dateFormatddMMyyyy dateFromString:lastDateOfStartYearString];
//no. of days
NSInteger year=[[dateFormatterYYYY stringFromDate:startDate]integerValue];
NSInteger days=[self daysBetweenTwoDates:startDate andDate:lastDateOfStartYear];
//add in dictionary
NSMutableDictionary *daysForYearDictionary=[NSMutableDictionary new];
[daysForYearDictionary setValue:#(days) forKey:[NSString stringWithFormat:#"%ld",year]];
/* step 2*/
NSInteger nextYearAfterStart=[[dateFormatterYYYY stringFromDate:startDate]integerValue]+1;
NSInteger previousYearBeforeEnd=[[dateFormatterYYYY stringFromDate:endDate]integerValue]-1;
for (NSInteger yearCounter=nextYearAfterStart; yearCounter<=previousYearBeforeEnd; yearCounter++) {
NSString *firstDateString=[NSString stringWithFormat:#"1/1/%ld",yearCounter];
NSDate *firstDate=[dateFormatddMMyyyy dateFromString:firstDateString];
NSString *lastDateString=[NSString stringWithFormat:#"31/12/%ld",yearCounter];
NSDate *lastDate=[dateFormatddMMyyyy dateFromString:lastDateString];
//no. of days
days=[self daysBetweenTwoDates:firstDate andDate:lastDate];
//add in dictionary
[daysForYearDictionary setValue:#(days) forKey:[NSString stringWithFormat:#"%ld",yearCounter]];
}
/* step 3 */
//find 1/1/EndDateYear
NSString *firstDateOfStartYearString=[NSString stringWithFormat:#"1/1/%#",[dateFormatterYYYY stringFromDate:endDate]];
NSDate *firstDateOfEndYear=[dateFormatddMMyyyy dateFromString:firstDateOfStartYearString];
//no. of days
year=[[dateFormatterYYYY stringFromDate:endDate]integerValue];
days=[self daysBetweenTwoDates:firstDateOfEndYear andDate:endDate];
//add in dictionary
[daysForYearDictionary setValue:#(days) forKey:[NSString stringWithFormat:#"%ld",year]];
//printing
for (NSString *yearStr in daysForYearDictionary) {
NSLog(#"Year : %#, Days Worked : %#",yearStr,[daysForYearDictionary valueForKey:yearStr]);
}
}