【Objective-c】小ネタ 年齢を計算する

さっきC#で書いたけど、やっぱりこっちでも必要になったので実装しましたw

- (NSInteger)getAgeByYear:(NSInteger)year month:(NSInteger)month day:(NSInteger)day
{
    NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
    
    NSDateComponents *components = [[NSDateComponents alloc] init];
    components.year = year;
    components.month = month;
    components.day = day;
    NSDate *birthDay = [calendar dateFromComponents:components];
    return [calendar components:NSYearCalendarUnit fromDate:birthDay toDate:[NSDate date] options:0].year;
}