// Source: "Software Design ...", John A Robinson, Newnes, 2004, page 158.
#include <fstream>
using namespace std;
#include "student.h"
float student_list::average_mark() const
	{
	float sum_marks = 0.0;
	for (int i = 0; i < num_students; i++)
		sum_marks += st[i]->get_mark();
	return(sum_marks/num_students);
	}

// The load_data method is the only one that needs to know the
// format of the data in the database file.
// This is shown in the following example line:
// a Alice_Brown 12345678 75.2 82.3
// The first character indicates the stream.
int student_list::load_data(const char *fname)
	{
	ifstream in(fname);
	if (!in)
		return(-1);
	in >> num_students;
	int i;
        char name[MAXNAMELENGTH];
        long idnumber;
        float mark1, mark2;
        char type;
	for (i = 0; i < num_students; i++)
		{
                in >> type >> name >> idnumber >> mark1 >> mark2;
		// Now set up appropriate type of student structure
		// and set pointer in st[]
		if (type == 'b')
			st[i] = new b_stream_student(name,
			idnumber, mark1, mark2);
		else
			st[i] = new a_stream_student(name,
			idnumber, mark1, mark2);
		}
	in.close();
	return(num_students);
	}


int software_design::work_out_marks()
	{
	for (int i = 0; i < num_students; i++)
		st[i]->calc_mark();
	return(0);
	}