iOS计算两天相差多少天

只需传入两个日期

/**任意两天相差天数*/

+ (NSInteger)getTheCountOfTwoDaysWithBeginDate:(NSString *)beginDate endDate:(NSString *)endDate{

    

    NSDateFormatter *inputFormatter = [[NSDateFormatter alloc] init];

    [inputFormatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"en_US"]];

    [inputFormatter setDateFormat:@"yyyy-MM-dd"];

    NSDate *startD =[inputFormatter dateFromString:beginDate];

    NSDate *endD = [inputFormatter dateFromString:endDate];

    // 当前日历

    NSCalendar *calendar = [NSCalendar currentCalendar];

    // 需要对比的时间数据

    NSCalendarUnit unit = NSCalendarUnitYear | NSCalendarUnitMonth

    | NSCalendarUnitDay;

    // 对比时间差

    NSDateComponents *dateCom = [calendar components:unit fromDate:startD toDate:endD options:0];

    

    return dateCom.day;

}