/* 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 <streambuf>#include <locale>#include <cstdio>class outbuf : public std::streambuf{  protected:    /* central output function     * - print characters in uppercase mode     */    virtual int_type overflow (int_type c) {        if (c != EOF) {            // convert lowercase to uppercase            c = std::toupper(c,getloc());            // and write the character to the standard output            if (putchar(c) == EOF) {                return EOF;            }        }        return c;    }};