#include <iostream> 
#include <string>
using namespace std; 
//
// Base class
//
class lu_student 
{ 
public:
    lu_student(int ssn);
    string  get_name();
    int     get_ssn();
    int     get_total_hr();
    double  get_gpa();
    void    change_name(string new_name);
    double  update(int hr, char grade);
private:
    int     my_ssn;
    string  my_name;
    double  my_gpa; 
    int     total_hr;
};

lu_student::lu_student(int ssn)
:my_ssn(ssn), my_gpa(0), total_hr(0)
{}

string lu_student::get_name()
{
    return my_name;
}

int lu_student::get_ssn()
{
    return my_ssn;
}

int lu_student::get_total_hr()
{
    return total_hr;
}

double lu_student::get_gpa()
{
    return my_gpa;
}

void lu_student::change_name(string new_name)
{
    my_name = new_name;
}

double lu_student::update(int hr, char grade)
{
    int p;

    switch (toupper(grade))
    {
    case 'A': p=4; break;
    case 'B': p=3; break;
    case 'C': p=2; break;
    case 'D': p=1; break;
    case 'F': p=0; break;
    default : cout << "Invalid Grade!!";
              return my_gpa;
    }
    my_gpa = (my_gpa*total_hr + p*hr)/(total_hr+hr);
    total_hr += hr;
    return my_gpa;
}


void print_lu_student(lu_student s)
{
    cout << s.get_name() << " SSN:" << s.get_ssn();
    cout << "  Total Hr: " << s.get_total_hr();
    cout << " GPA = " << s.get_gpa() << endl;
}

void use_lu_student()
{
    char grade;
    string name;
    lu_student s(123456789);

    cout << "Input name:";
    cin >> name;
    s.change_name(name);

    while (true)
    {
        cout << "\n Input a grade (x to exit):";
        cin >> grade;
        if (toupper(grade) == 'X') break;
        s.update(3,grade);
        print_lu_student(s);
    }
}

//
//
//  Derived class 
//
class cs_student : public lu_student 
{ 
public:
    cs_student(int ssn);
    int     get_cs_hr();
    double  get_cs_gpa();
    double  cs_update(int hr, char grade);
    void    change_name(string first_name, string last_name);
private:
    double  my_cs_gpa; 
    int     cs_hr;
};


cs_student::cs_student(int ssn)
:lu_student(ssn), my_cs_gpa(0), cs_hr(0)
{
}

int cs_student::get_cs_hr()
{
    return cs_hr;
}

double cs_student::get_cs_gpa()
{
    return my_cs_gpa;
}


void cs_student::change_name(string first_name, string last_name)
{
    lu_student::change_name(first_name + " " + last_name);
}

double cs_student::cs_update(int hr, char grade)
{
    int p;

    switch (toupper(grade))
    {
    case 'A': p=4; break;
    case 'B': p=3; break;
    case 'C': p=2; break;
    case 'D': p=1; break;
    case 'F': p=0; break;
    default : cout << "Invalid Grade!!";
              return my_cs_gpa;
    }
    my_cs_gpa = (my_cs_gpa*cs_hr + p*hr)/(cs_hr+hr);
    cs_hr += hr;
    update(hr,grade);
    return my_cs_gpa;
}



void print_cs_student(cs_student s)
{
    cout << endl << s.get_name() << " SSN:" << s.get_ssn();
    cout << "\nTotal Hr: " << s.get_total_hr();
    cout << "    GPA = " << s.get_gpa();
    cout << "\n   CS Hr: " << s.get_cs_hr();
    cout << " CS GPA = " << s.get_cs_gpa() << endl;
}


void use_cs_student()
{
    char grade;
    string fname,lname;
    cs_student s(123456789);

    cout << "Input first name:";
    cin >> fname;
    cout << "Input last name:";
    cin >> lname;
    s.change_name(fname,lname);

    while (true)
    {
        cout << "\n Input a CS grade (x to exit):";
        cin >> grade;
        if (toupper(grade) == 'X') break;
        s.cs_update(3,grade);
        cout << "Input a none CS grade (x to exit):";
        cin >> grade;
        if (toupper(grade) == 'X') break;
        s.update(3,grade);
        print_cs_student(s);
    }

    print_lu_student(s);   // No problem!!
}

//
//
//  Derived class 
//
class cpp_student : public cs_student 
{ 
public:
    cpp_student(int ssn);
    int     get_score();
    char    get_grade();
    void    update(int score);
private:
    int     my_score;
};


cpp_student::cpp_student(int ssn)
: cs_student(ssn), my_score(0)
{
}

int cpp_student::get_score()
{
    return my_score;
}
    
char cpp_student::get_grade()
{
    if (my_score >= 90) return 'A';
    if (my_score >= 80) return 'B';
    if (my_score >= 70) return 'C';
    if (my_score >= 60) return 'D';
    return 'F';
}

void cpp_student::update(int score)
{
    my_score = score;
    cs_student::cs_update(3, get_grade());
}



void main()
{
    cout << "\n***** use_lu_student():: *******\n";
    use_lu_student();
    cout << "\n***** use_cs_student():: *******\n";
    use_cs_student();
}