Qt 5.7 | Qt Charts | Box and Whiskers Example | boxdatareader.cpp Example File

Qt 5.7.1 Reference Documentation

# boxdatareader.cpp Example File

boxplotchart/boxdatareader.cpp

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      ** Contact: https://www.qt.io/licensing/
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      #include "boxdatareader.h"

      BoxDataReader::BoxDataReader(QIODevice *device) :
          QTextStream(device)
      {
      }

      void BoxDataReader::readFile(QIODevice *device)
      {
          QTextStream::setDevice(device);
      }

      QBoxSet *BoxDataReader::readBox()
      {
          QString line = readLine();
          if (line.startsWith("#"))
              return 0;

          QStringList strList = line.split(" ", QString::SkipEmptyParts);

          sortedList.clear();
          for (int i = 1; i < strList.count(); i++)
              sortedList.append(strList.at(i).toDouble());

          qSort(sortedList.begin(), sortedList.end());

          int count = sortedList.count();

          QBoxSet *box = new QBoxSet(strList.first());
          box->setValue(QBoxSet::LowerExtreme, sortedList.first());
          box->setValue(QBoxSet::UpperExtreme, sortedList.last());
          box->setValue(QBoxSet::Median, findMedian(0, count));
          box->setValue(QBoxSet::LowerQuartile, findMedian(0, count / 2));
          box->setValue(QBoxSet::UpperQuartile, findMedian(count / 2 + (count % 2), count));

          return box;
      }

      qreal BoxDataReader::findMedian(int begin, int end)
      {
          int count = end - begin;
          if (count % 2) {
              return sortedList.at(count / 2 + begin);
          } else {
              qreal right = sortedList.at(count / 2 + begin);
              qreal left = sortedList.at(count / 2 - 1 + begin);
              return (right + left) / 2.0;
          }
      }