iOS 获取某年某月的天数的示例

在限定一个月的时间间隔为第一天和最后一天，需要知道这个月有多少天，才能知道最后一天是多少号，而且还要知道是否是闰年，可能2月只有28天。
附上代码：

- (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;
}