// shared_ptr_grades.cc
// for g++ compiled with: 
// g++ -std=c++11 -o shared_ptr_grades shared_ptr_grades.cc
#include <iostream>
#include <string>
#include <vector>
#include <memory>  // for shared_ptr
using namespace std;

class ClassGrades
{
  private:
    string Name;
    int* Grades;
  
  public:
    ClassGrades(string inName) {
      cout << "In constructor for record " << inName << endl;
      Name = inName;
      Grades = new int[3]; // assume 3 assignments
      for (int i=0; i<3; i++) { Grades[i] = 0; }
    }
    ~ClassGrades() {
      cout << "In destructor for record " << Name << endl;
      if (Grades != NULL) delete [] Grades; 
    }
    int& operator [] (int Index) {
      if (Index >=0 && Index < 3) {
        return Grades[Index];
      }
    }
    void PrintGrades() {
      cout << "Student " << Name << " has grades: ";
      for (int i=0; i<3; i++) {
        cout << Grades[i] << " ";
      }
      cout << endl;
    }
};

int main()
{
  // This time we will dynamically allocate students using new, and we
  // will handle the pointers using smart pointers so we don't have to
  // explicitly remember to delete the ClassGrades objects
  vector<shared_ptr<ClassGrades>> StudentList;

  // Just make 2 of them for simplicity
  int NumStudents = 2;
  for (int i=0; i<NumStudents; i++) {
    // make a shared pointer to a new student
    if (i==0) {
      shared_ptr<ClassGrades> NewStudent(new ClassGrades("John Smith"));
      (*NewStudent)[0] = 70; (*NewStudent)[1] = 72; (*NewStudent)[2] = 86;
      StudentList.push_back(NewStudent);
    }
    else if (i==1) {
      shared_ptr<ClassGrades> NewStudent(new ClassGrades("Sally Brown"));
      (*NewStudent)[0] = 82; (*NewStudent)[1] = 90; (*NewStudent)[2] = 80;
      StudentList.push_back(NewStudent);
    }
  }

  // iterate through the vector
  for (int i=0; i<StudentList.size(); i++) {
    cout << "Grades for student #" << i << ":" << endl;
    StudentList[i]->PrintGrades();
  }

  // we created the ClassGrades objects with new but they will delete
  // themselves when the smart pointers go out of scope
}