Ios 如何计算两个日期之间特定日期的计数？

我想要两个日期之间某一天的总计数。我想要做一个函数，返回某一天的总计数。 例如：如果我通过了星期一、开始日期和结束日期，那么它将返回这些日期之间星期一的总计数

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如果我将日期作为星期一，开始日期为2014-10-04，结束日期为2014-10-18，那么函数应该是星期一的返回计数为2，我可以告诉你一个简单的计算逻辑。如果是星期一（开始日期A），下一个星期一将是7天后。。。因此，在开始日期加上7天，检查下一个日期（开始日期B）是否小于结束日期，如果不是，再次在开始日期（开始日期B）加上7天，再次检查这是否小于结束日期。据此计算。做这样的事

    NSDateComponents *dateComponents = [NSDateComponents new];
        dateComponents.day = 7;
        NSDate *DateWithAdditon = [[NSCalendar currentCalendar]dateByAddingComponents:dateComponents   toDate: StartDate
                                                                      options:0];

        NSDateFormatter *dateFormatter=[[NSDateFormatter alloc]init];
        [dateFormatter setDateFormat:@"dd/MM/yyyy"];
        [dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];
        NSString *DateWithAdditonString=  [ dateFormatter stringFromDate:DateWithAdditon];

        NSLog(@"your next monday will be here %@ ",DateWithAdditonString );


//Write code to check wheather the DateWith addition is lesser than the End date if not add another 7 days and increase the count accordingly

我自己找到了解决办法

-(int)countDays:(int)dayCode startDate:(NSDate *)stDate endDate:(NSDate *)endDate 
{

    // day code is Sunday = 1 ,Monday = 2,Tuesday = 3,Wednesday = 4,Thursday = 5,Friday = 6,Saturday = 7

    NSInteger count = 0;

    // Set the incremental interval for each interaction.
    NSDateComponents *oneDay = [[NSDateComponents alloc] init];
    [oneDay setDay:1];

    // Using a Gregorian calendar.
    NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

    NSDate *currentDate = stDate;

    // Iterate from fromDate until toDate
    while ([currentDate compare:endDate] == NSOrderedAscending) {

        NSDateComponents *dateComponents = [calendar components:NSWeekdayCalendarUnit fromDate:currentDate];

        if (dateComponents.weekday == dayCode) {
            count++;
        }

        // "Increment" currentDate by one day.
        currentDate = [calendar dateByAddingComponents:oneDay
                                            toDate:currentDate
                                           options:0];
    }
    NSDateComponents* component = [calendar components:NSWeekdayCalendarUnit fromDate:endDate];
    int weekDay = [component weekday];
    if (weekDay == dayCode) { // Condition if end date contain your day then count should be increase
        count ++ ;
    }
    return count; // Return your day count
}