How do I populate an object array from a csv text file with multiple lines cpp

Question

I have a file, 'staff.txt' that I populate using the function below:

void writeToFile(){
    ofstream myFile;
    myFile.open("staff.txt",std::ofstream::out | std::ofstream::app);
    myFile << staffCode << ",";
    myFile << firstName << endl;    
    myFile.close();  
  }

The file stores instances of the Staff class:

class Staff{
public:
  int staffCode;
  string firstName;
  string lastName;

  void getData(){
    cout << "\nPlease enter the following information" << endl;
    cout << "Staff Code: ";
    cin >> staffCode;
    cout << "First Name: ";
    cin >> firstName;
    cout << "Last Name: ";
    cin >> lastName;
  }
  void showData(){
    cout << "Staff Code: " << staffCode << endl;
    cout << "Name: " << firstName + " " + lastName << endl;
  }

  void writeToFile(){
    ofstream myFile;
    myFile.open("staff.txt",std::ofstream::out | std::ofstream::app);
    myFile << staffCode << ",";
    myFile << firstName << endl;    
    myFile.close();  
  }
};

I would like to read the data in the file into an object array of the Staff class.

This is what I currently have:

int linesInFile = 0;
    int i = 0;
    string line;
    ifstream myFile("staff.txt");

    while (getline(myfile, line)){
        ++linesInFile;
    }
    Staff myStaff[linesInFile];
    if (myFile.is_open()){
        while (myFile.good()){
            myFile.getline()
        }
    }