/* The following code example is taken from the book * "The C++ Standard Library - A Tutorial and Reference" * by Nicolai M. Josuttis, Addison-Wesley, 1999 * * (C) Copyright Nicolai M. Josuttis 1999. * Permission to copy, use, modify, sell and distribute this software * is granted provided this copyright notice appears in all copies. * This software is provided "as is" without express or implied * warranty, and with no claim as to its suitability for any purpose. */#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    }}