cpp

multithread.cpp

QList<QVector<int> > resultContainter;

QVector<int> Calculate(int begin, int end)
{
	QVector<int> localResult(30);
	for (int i = begin; i < end; ++i)
	{
		localResult[aData[i]]++;
	}
	return localResult;
}

int main(int argc, char *argv[])
{
	QApplication a(argc, argv);

	int nThreadCount = QThread::idealThreadCount();
	int nOffset = qCeil(aData.count() / (double)nThreadCount);

	QFutureSynchronizer<QVector<int>> synchronizer;

	for (int i = 0; i < aData.count(); i += nOffset)
	{
		if ((i + nOffset) >= aData.count())
			break;
		
		synchronizer.addFuture(QtConcurrent::run(Calculate, i, i + nOffset));
	}

	synchronizer.waitForFinished();

	for (int i = 0; i < synchronizer.futures().count(); i++)
	{
		resultContainter.append(synchronizer.futures().at(i).result());
	}

	synchronizer.clearFutures();

	return a.exec();
}