Calculating the end of a month, or its last second

Question

I have the simplest of tasks that I can't figure out how to do correctly. With the snippet below I can find out the beginning of a month.

NSCalendar *cal = [NSCalendar currentCalendar];
NSDate *beginning = nil;
[cal rangeOfUnit:NSMonthCalendarUnit startDate:&beginning interval:NULL forDate:self];
return beginning;

Now I want to determine the end of that same month (the last second at 23:59:59 would suit my purposes). My first thought was to start at the first day of the next month and subtract a second. But I couldn't break down the date in an NSDateComponent instance to [dateComponents setMonth:[dateComponents month] + 1], because in the case of December that method wouldn't accept 12 + 1 = 13 to get to January, right?

Then how would I get to the last second of a month?

Answer 1

Do this to get the beginning of next month:

NSDateComponents *comps = [[NSDateComponents alloc] init];
[comps setMonth:1];
NSDate *beginningOfNextMonth = [cal dateByAddingComponents:comps toDate:beginning options:0];
[comps release];