io/streamreadwrite1.cpp

The following code example is taken from the book
The C++ Standard Library - A Tutorial and Reference, 2nd Edition
by Nicolai M. Josuttis, Addison Wesley Longman, 2012
Copyright © 2012 by Pearson Education, Inc. and Nicolai M. Josuttis


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

int main()
{
    // open file "example.dat" for reading and writing
    filebuf buffer;
    ostream output(&buffer);
    istream input(&buffer);
    buffer.open ("example.dat", ios::in | ios::out | ios::trunc);

    for (int i=1; i<=4; i++) {
        // write one line
        output << i << ". line" << endl;

        // print all file contents
        input.seekg(0);          // seek to the beginning
        char c;
        while (input.get(c)) {
            cout.put(c);
        }
        cout << endl;
        input.clear();           // clear  eofbit and  failbit
    }
}