#include<conio.h>
#include<stdio.h>
#include<iostream.h>
#include<iomanip.h>
#include<windows.h>
void main()
{
  cout<<setiosflags(ios::unitbuf); 
  cout<<"This program toggles the bits for Port A and Port B.";
  _outp(0x303,0x80); 
  do
  {
    _outp(0x300,0x55); 
    _outp(0x301,0x55); 
    _sleep(500); 
    _outp(0x300,0xAA); 
    _outp(0x301,0xAA);
    _sleep(500);
    }
  while(!kbhit());
  }