How to find last day of week in iPhone? - iphone

Question

In my application I'm using following codes to retrieve current date and day :-
NSDate *today1 = [NSDate date]; NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init]; [dateFormat setDateFormat:#"dd/MM/yyyy :EEEE"]; NSString *dateString11 = [dateFormat stringFromDate:today1];
NSLog(#"date: %#", dateString11);
//[dateFormat release];
NSCalendar *gregorian11 = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];  
NSDateComponents *components1 = [gregorian11 components:NSWeekdayCalendarUnit | NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit fromDate:today1];
[components1 setDay:([components1 day]-([components1 weekday]-1))];
NSDate *beginningOfWeek1 = [gregorian11 dateFromComponents:components1];
NSDateFormatter *dateFormat_first = [[NSDateFormatter alloc] init];
[dateFormat_first setDateFormat:#"dd/MM/yyyy :EEEE"];
NSString *dateString_first = [dateFormat_first stringFromDate:beginningOfWeek1];
NSLog(#"First_date: %#", dateString_first);
[components1 setDay:([components1 day]-([components1 weekday]-1) + 6)]; now =[gregorian dateFromComponents:components1]; [format setDateFormat:#"dd/MM/yyyy :EEEE"]; dateString = [format stringFromDate:now]; NSLog(#" week Last_date: %#", dateString);
but using above code I only got the current day and Date and first day of week but I need to get last day of week. But it gives the wrong output. Where am I wrong in my code and what modification is needed to get last day/date of week?

Answer 1

When you call setDay: you are sometimes setting it to a negative day. I don't know if setDay and/or dateFromComponents: will handle that.
To create a NSDate for a date/time that is in the past (or future) you can subtract (or add) the number of seconds that you want to go back (or forward), like this:
// convert to seconds
NSTimeInterval tmpSecs = [[NSDate date] timeIntervalSinceReferenceDate];
// Shift the date/time (in seconds) to a new date X days away:
tmpSecs += daysOffset * 86400; // 86400 seconds per day
// convert back to NSDate and return the result
return [NSDate dateWithTimeIntervalSinceReferenceDate:tmpSecs];