Help in c++ fstream file position example

#include <fstream>
#include <iostream>
#include <vector>

using namespace std;

int main()
{
    fstream file("highscores.txt",ios::in | ios::out);
    file.seekp(0);
    file.seekg(0);
    if (! file.is_open())
    {
        cout << "Could not open the file";
        return 0;
    }
    int new_high_score;
    cout << "Enter a new high score : ";
    cin >> new_high_score;
    streampos pre_score_pos = file.tellg();
    int cur_score;
    while (file >> cur_score)
    {
        if (new_high_score > cur_score)
        {
            break;
        }
        pre_score_pos = file.tellg();
    }
    if (file.fail() && !file.eof())
    {
        cout << "Some bad inputs";
        return 0;
    }
    file.clear();
    file.seekg(pre_score_pos);
    vector<int> scores;
    while (file >> cur_score)
    {
        scores.push_back(cur_score);
    }
    if (!file.eof())
    {
        cout<< "Some bad inputs";
        return 0;
    }
    file.clear();
    file.seekp(pre_score_pos);
    if (pre_score_pos != 0)
    {
        file << endl;
    }
    file << new_high_score << endl;
    for (vector<int>::iterator itr = scores.begin(); itr != scores.end(); ++itr)
    {
        file << *itr << endl;
    }
}