Sort QVector of pointers to custom objects

Question

My Question:

What is the best way to assign numbers to each Camera in a QVector<Camera*> where the following specifications should apply:

• The unsorted QVector should keep its order
• The int number of each Camera should be assigned depending on its QString macAddress
• The int number should start with 0 for the "lowest" macAddress (QString::operator<)

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Sources:

class Camera {
    int number;
    QString macAddress;
}

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Current solution:

My curent solution is to:

• Implement Camera::operator<

  bool Camera::operator<(const Camera &cam) const {
      return(this->macAddress < cam.macAddress);
  }
  

• Implement a compare struct

  struct CameraCompare {
      bool operator()(const Camera *a, const Camera *b) {
          return(*a < *b);
      }
  }
  

• Create a temporary QVector of pointers to the same Camera-objects and then using std::sort on the temporary vector and assigning the numbers like the following:

  QVector<Camera*> tempVector;
  for(quint8 i = 0; i < cameras->size(); i++) {
      Camera *temp = (*cameras)[i];
      tempVector.append(temp);
  }
  std::sort(tempVector.begin(), tempVector.end(), CameraCompare());
  for(quint8 i = 0; i < tempVector.size(); i++) {
      tempVector[i]->setNumber(i); // Edited
  }
  

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Edit: My question now is: Is there a better way to accomplish this?

Answer 1

There's nothing wrong with your solution. It sorts the vector fine. But it seems there's something wrong here:

for(quint8 i = 0; i < tempVector.size(); i++) {
    cameras->at(i)->setNumber(i);
}

This code sets the number of each camera, the index of it in the original vector NOT the sorted vector. I think it should be replaced with:

for(quint8 i = 0; i < tempVector.size(); i++) {
    int number = tempVector.indexOf(cameras.at(i));
    cameras->at(i)->setNumber(number);
}