[Qt-interest] Iterate over weeks of a timespan

[Sven Grunewaldt]

Sven Grunewaldt schrieb:
> Hi,
> 
> I need to iterate over all the weeks of a specific time period
> (f.e. 09.2006 to 06.2009)
> 
> My current approach:
> 	int startYear = 2006;
> 	int startMonth = 9;
> 	int endYear = 2009;
> 	int endMonth = 6;
> 	QDate startDate = QDate(startYear, startMonth, 1);
> 	QDate endDate = QDate(endYear, endMonth, 30); // I know that the  day
> value here is stupid, it will be replaced by a Date Edit
> 
> 	for (int i = startYear; i <= endYear; i++)
> 	{
> 		int firstWeek;
> 		int lastWeek;
> 
> 		if (i == startYear)
> 			firstWeek = startDate.weekNumber();
> 		else
> 			firstWeek = QDate(i, 1, 1).weekNumber();
> 
> 		if (i == endYear)
> 			lastWeek = endDate.weekNumber();
> 		else
> 			lastWeek = QDate(i, 12, 31).weekNumber();
> 		
> 		for (int j = firstWeek; j <= lastWeek; j++)
> 			do_something(i, j);
> 	}
> 
> The first problem is:
> I can't figure out the last Week of a year.
> 
> The second problem is:
> If the startMonth or endMonth happens to be at the very beginning or end
> of a year, the week could 53 for the startMonth or 1 for the endMonth,
> which breaks the whole for-loop.
> I think I can solve this for myself, I only mention it to avoid confusion.
> 
> Sadly I'm at a complete loss how to solve this puzzle.
> It would be great if someone could give me a pointer how to do it correctly.
> Regards,
> Sven Grunewaldt
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Oups, forgot to mention the position of the first problem.
It occures here when the loop is not in the end year:

> 		if (i == endYear)
> 			lastWeek = endDate.weekNumber();
> 		else
> 			lastWeek = QDate(i, 12, 31).weekNumber();

The last day of december could be the first week of the next year, but I
need the last week of year "i". At least in my approach...