IOS获取指定年月的当月天数

- (void)viewDidLoad {
  [super viewDidLoad];
  // Do any additional setup after loading the view, typically from a nib.
  NSLog(@"%ld",(long)[self howManyDaysInThisYear:2016 withMonth:1]);
  NSLog(@"%ld",(long)[self howManyDaysInThisYear:2016 withMonth:2]);
  NSLog(@"%ld",(long)[self howManyDaysInThisYear:2016 withMonth:3]);
  NSLog(@"%ld",(long)[self howManyDaysInThisYear:2016 withMonth:4]);
  NSLog(@"%ld",(long)[self howManyDaysInThisYear:2016 withMonth:5]);
  NSLog(@"%ld",(long)[self howManyDaysInThisYear:2016 withMonth:6]);
  NSLog(@"%ld",(long)[self howManyDaysInThisYear:2016 withMonth:7]);
  NSLog(@"%ld",(long)[self howManyDaysInThisYear:2016 withMonth:8]);
}
#pragma mark - 获取某年某月的天数
- (NSInteger)howManyDaysInThisYear:(NSInteger)year withMonth:(NSInteger)month{
  if((month == 1) || (month == 3) || (month == 5) || (month == 7) || (month == 8) || (month == 10) || (month == 12))
    return 31 ;
 
  if((month == 4) || (month == 6) || (month == 9) || (month == 11))
    return 30;
 
  if((year % 4 == 1) || (year % 4 == 2) || (year % 4 == 3))
  {
    return 28;
  }
 
  if(year % 400 == 0)
    return 29;
 
  if(year % 100 == 0)
    return 28;
 
  return 29;
}