C++ OOP, problem with reading file, EOF used two times, leaderboard - c++

Question

I am working on a little game and I want to make a leaderboard. I have class leaderboard and I am creating dynamic table, depending on how many players in the leaderboard.txt are. So that's one while eof loop. Then i want to asign names and points to these dynamic tables in leaderboard class. Problem is that i get random numbers instead of names and points. For me the code looks good. Any help?
class Leaderboard
{
int max_counter;
int counter;
int *points;
string *name;
string filename;
public:
Leaderboard(string n_file)
{
counter = 0;
filename = n_file;
}
string get_file(){return filename;}
void set_counter(int n_counter)
{
max_counter = n_counter;
points = new int[n_counter];
name = new string[n_counter];
}
void add_value(string n_name, int n_points)
{
name[counter] = n_name;
points[counter] = n_points;
counter++;
}
void show()
{
for(int i=0;i<max_counter;i++)
{
cout << name[i] << " " << points[i] << endl;
}
}
};
AND main:
Leaderboard *top = new Leaderboard("leaderboard.txt");
fstream file;
file.open(top->get_file(), ios::in);
if(file.good())
{
string name;
int points;
int counter = 0;
while(!(file.eof()))
{
file >> name >> points;
counter++;
}
counter--;
top->set_counter(counter);
while(!(file.eof()))
{
file >> name >> points;
top->add_value(name,points);
}
cout << "Dodano pomyslnie" << endl;
system("pause");
top->show();
file.close();
}
else cout << "Blad z plikiem!" << endl;
delete top;
break;

Answer 1

A couple of errors
while(!(file.eof()))
{
file >> name >> points;
counter++;
}
should be
while (file >> name >> points)
{
counter++;
}
Second error, you can't expect the file to magically go back to the beginning just because you want it to. You have to tell it to.
while (file >> name >> points)
{
...
}
file.clear(); // clear error state
file.seekg(0); // go to beginning of file
while (file >> name >> points)
{
...
}

Answer 2

Allow me to suggest that the general approach you're using here is open to considerable improvement.
Right now, our main knows (and has to know) a great deal about the internals of the Leaderboard to do its job.
It would be better if that were not required. The Leaderboard itself should be the only part that knows about its internals.
Let me go a bit further though: a leaderboard is basically just a collection of scores. It shouldn't know or care about the internal details of an individual score either.
Finally, let me suggest that you consider using a container from the standard library. In your case, it appears that std::vector will work quite nicely.
#include <iostream>
#include <vector>
#include <iterator>
#include <vector>
#include <fstream>
#include <algorithm>
class score {
std::string name;
int points;
public:
friend std::istream& operator>>(std::istream& is, score& s) {
return is >> s.name >> s.points;
}
friend std::ostream& operator<<(std::ostream& os, score const& s) {
return os << s.name << ": " << s.points;
}
};
class leaderboard {
std::vector<score> scores;
public:
friend std::istream& operator>>(std::istream& is, leaderboard& l) {
std::copy(
std::istream_iterator<score>(is), std::istream_iterator<score>(),
std::back_inserter(l.scores));
return is;
}
friend std::ostream& operator<<(std::ostream& os, leaderboard const& l) {
for (auto const& s : l.scores)
os << s << "\n";
return os;
}
};
int main() {
leaderboard scores;
std::ifstream in("leaderboard.txt");
in >> scores;
std::cout << "Top scores\n";
std::cout << scores;
}
Of course there's more that almost certainly should be done, such as sorting the scores in descending order by score, so the person with the top score shows up first--but that's kind of a separate issue.