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

int main()
{
    const char* filename = "ex2data.bin";

    ofstream fout(filename);
    if (!fout) {
        cerr << "Unable to open output file " << filename << endl;
        exit(1);
    }

    fout.write("Have a nice day",strlen("Have a nice day."));

    int age = 35;
    double gpa = 3.5;

    fout.write(reinterpret_cast<char*>(&age),sizeof(int));
    fout.write(reinterpret_cast<char*>(&gpa),sizeof(gpa));

    cout << fout.tellp() << endl;
    fout.seekp(0,ios::end);
    cout << fout.tellp() << endl;

    fout.seekp(sizeof("Have a ")-1,ios::beg);
    cout << fout.tellp() << endl;
    fout.write("good",4);
    cout << fout.tellp() << endl;
    fout.close();
}