streambuf.cc File Reference

Demonstration of streambuf inheritance. More...

#include <iostream>
#include <cstdio>

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Classes
class	dmsg
	Demonstration of streambuf inheritance. More...

Functions
int	main (int argc, char **argv)

Detailed Description

Demonstration of streambuf inheritance.

Purpose:

Program that demonstrates inheriting from streambuf to act just like cout. The program comes from chapter 13 of "The C++ Standard Library" (Josuttis).

Also demonstrates the values of various types of variables when instantiated.

Definition in file streambuf.cc.

Function Documentation

int main	(	int	argc,
		char **	argv
	)

Definition at line 47 of file streambuf.cc.

References dmsg::i, and dmsg::p.

{
  dmsg X;
  std::ostream out(&X);

  out << "xxx " 
      << 123
      << " yyy"
      << std::endl;

  std::cout << "blah" << std::endl;


  /* demonstrate compound input from a stream
     (for example type "2xx4y [enter]" at the prompt)
  */
  int i;
  char ch;
  std::cout << std::endl;
  std::cout << "i="<< i << "|ch="<<ch<<std::endl;
  std::cout << "prompt:";
  std::cin >> i >> ch;
  std::cout << "i="<< i << "|ch="<<ch<<std::endl;

  /* demonstrate the contents of variables when they are created
   */
  dmsg *msg_p = new dmsg();

  if(msg_p->p == NULL)
    std::cout << "msg_p->p is NULL" << std::endl;

  if(msg_p->i == 0)
    std::cout << "msg_p->i is ZERO" << std::endl;

  delete msg_p;


  int *i_p;

  if(i_p)
    std::cout << "i_p is VALID" << std::endl;

  if(i_p == NULL)
    std::cout << "i_p is NULL" << std::endl;
  else
    if(i_p == 0)
      std::cout << "i_p is ZERO" << std::endl;

  i_p = new int;

  if(*i_p == 0)
    std::cout << "*i_p is ZERO" << std::endl;
  else
    std::cout << "*i_p=" << *i_p <<std::endl;

  delete i_p;
}