In this lesson, you will use the csv reader functionality to input this visit data from a csv file. You use the classes IloCsvReader, IloCsvReader::Iterator, and IloCsvLine. This code is provided for you:

void RoutingModel::createVisits(const char* visitsFileName) {
  IloCsvReader csvVisitReader(_env, visitsFileName);
  IloCsvReader::LineIterator  it(csvVisitReader);
  while(it.ok()){
    IloCsvLine line = *it;
    //read visit data from files
    char * visitName =  line.getStringByHeader("name");
    char * nodeName = line.getStringByHeader("node");
    IloNum quantity = line.getFloatByHeader("quantity");
    IloNum minTime  = line.getFloatByHeader("minTime");
    IloNum maxTime  = line.getFloatByHeader("maxTime");
    IloNum dropTime = line.getFloatByHeader("dropTime");

Next, you use the static member function IloNode::Find to find the node associated with the visit.

Add the following code after the comment //Find the visit node

    IloNode node = IloNode::Find(_env, nodeName);

Next, you create a visit using an instance of IloVisit. The constructor for IloVisit takes two parameters: an instance of IloNode and a name for debug and trace purposes. The instance of IloNode represents the location of the visit. You add the constraint that the amount of delay time at the visit must equal the drop time. You add the constraint that the amount of weight dropped off at the visit must equal the quantity of goods to be delivered at the visit. You also add the constraint that the visit must be performed within the visit time window.

Add the following code after the comment
//Create the visit and add constraints

    IloVisit visit(node, visitName);
    _mdl.add(visit.getDelayVar(_time) == dropTime);
    _mdl.add(visit.getTransitVar(_weight) == quantity);
    _mdl.add(minTime <= visit.getCumulVar(_time) <= maxTime);

Then, you add the visit to the model.

Add the following code after the comment //Add the visit to the model

    _mdl.add(visit);

Finally, you move to the next line in the csv file. When the end of the file is reached, you deallocate the memory used by the csv reader. This code is provided for you:

    ++it;
  }
  csvVisitReader.end();
}