/*
 * files.cpp
 *
 *  Created on: 17.10.2012
 *      Author: trifon
 */

#include <fstream>
#include <iostream>
#include <cstring>
using namespace std;

void essay() {
	fstream f("essay.txt");
	char line[100];
	f.getline(line, 100);
	f << "DO NOT READ THIS!\n";
	cout << "The line is: " << line;
}

class Student {
private:
	int fn;
	double grade;
	char name[40];
public:
	Student(int _fn, double _grade, char const* _name) :
		fn(_fn), grade(_grade)
	{
		strncpy(name, _name, 39);
		name[39] = '\0';
	}
	friend istream& operator>>(istream&, Student&);
	friend ostream& operator<<(ostream&, Student const&);
};

istream& operator>>(istream& is, Student& s) {
	is >> s.fn >> s.grade;
	is.getline(s.name, 40);
	return is;
}

ostream& operator<<(ostream& os, Student const& s) {
	os << s.fn << " " << s.grade << " " << s.name << endl;
	return os;
}

void writeText() {
	Student s1(40000, 5.50, "Иван Петров");
	Student s2(40001, 3.50, "Петър Иванов");
	Student s3(40002, 6.00, "Петър Петров");
	ofstream fo("students.txt");
	fo << s1 << s2 << s3;
}

void readText() {
	Student s(0, 0, "");
	ifstream fi("students.txt");
	ofstream fo("students.dat", ios::out | ios::binary);
	while (fi >> s)
	{
		cout << "Прочетох студент: " << s;
		fo.write((char const*)&s, sizeof(s));
	}
}

void readBinary() {
	Student s(0, 0, "");
	ifstream fi("students.dat", ios::in | ios::binary);
	while (fi.read((char*)&s, sizeof(s))) {
		cout << "От students.dat: " << s;
	}
}

Student readStudent(int i) {
	Student s(0, 0, "");
	ifstream fi("students.dat", ios::in | ios::binary);
	fi.seekg(i * sizeof(Student));
	fi.read((char*)&s, sizeof(s));
	if (!fi)
	{
		cerr << "Няма такъв студент!";
		return s;
	}
	cout << "Студент с пореден номер " << i;
	cout << ": " << s;
	return s;
}

void writeStudent(int i, Student const& s) {
	fstream fo("students.dat", ios::in | ios::out | ios::binary);
	fo.seekp(i * sizeof(Student));
	fo.write((char const*)&s, sizeof(s));
}


int main() {
//	essay();
//	writeText();
//	readText();
//	Student s(0, 0,"");
//	cin >> s;
	readBinary();
//	writeStudent(2, readStudent(1));
//	Student s(40003, 3.20, "Георги Петров");
//	writeStudent(10000, s);

	return 0;
}