Program to calculate the Typing Speed

/*Program is written in c u just save it with extension .cpp . Because this program uses class and friend function so it's a cpp programm */

#include  <stdio.h>
#include  <dos.h>
#include  <conio.h>
#define   ESC 0x1b
#define   BSPACE 0x08

const unsigned long far * const dosTime = (const unsigned long far * const)MK_FP( 0x40, 0x6C );

class Timer
{

public:

    Timer();
    void start();
    void stop();
    void reset();
    int status();
    double time();
    static double resolution();
private:

    static unsigned adjust;
    static unsigned calibrate();
    int running;
    struct TIME
         {
         unsigned long dosCount;
         unsigned timerCount;
         };
    TIME startTime;
    double time_;
};

inline double Timer::time()
{
    return time_/1.E6;
}

inline double Timer::resolution()
{
    return 839/1.E9;
}

unsigned Timer::adjust = calibrate();

Timer::Timer() : time_(0), running(0)
{
}

void Timer::start()
{
    if( !running )
         {
         outportb( 0x43, 0x34 );
         asm jmp __1;
    __1:
         outportb( 0x40, 0 );
         asm jmp __2;
    __2:
         outportb( 0x40, 0 );
         startTime.dosCount = *dosTime;
         startTime.timerCount = 0;
         running = 1;
         }
}

void Timer::stop()
{
    outportb( 0x43, 0 );
    unsigned char temp = inportb( 0x40 );

    TIME stopTime;
    stopTime.timerCount = (inportb( 0x40 ) << 8) + temp;
    stopTime.dosCount = *dosTime;

    TIME elapsedTime;
    elapsedTime.dosCount = stopTime.dosCount - startTime.dosCount;
    elapsedTime.timerCount = -( stopTime.timerCount - adjust );

    const double fudge = 83810.0/100000.0;
    time_ += ((elapsedTime.dosCount << 16) +
elapsedTime.timerCount)*fudge;

    running = 0;

}

void Timer::reset()
{
    time_ = 0;
    if( running )
         start();
}

unsigned Timer::calibrate()
{
    adjust = 0;
    unsigned long sum = 0;
    Timer w;
    for( int i = 0; i < 100; i++ )
         {
         w.start();
         w.stop();
         sum += w.time();
         w.reset();
         }
    return (unsigned)((sum+5)/100);
}


void main()
{
 clrscr();
 Timer t;
 char text[1000];
 int i = 0, space_count = 0, letter_count = 0;
 float duration;
 printf("PROGRAM TO TEST TYPING SPEED\n");
 printf("Hit any key to start timer..\n");
 if(getch())
   {
    printf("Your time has started. Start typing. Hit Esc when done.\n");
    t.start();
   }
 while(1)
 {
   text[i] = getche();
   letter_count++;
   if(text[i] == ' ')
      space_count++;
   if(text[i] == ' ')
      printf("");
   if(text[i] == BSPACE)
      printf(" "); // to erase previous character instead of cursoring over
   if(text[i] == ESC)
    {
      printf(" ");
      // to eliminate a special character that is printed for Esc
      // A Backspace followed by Space erases previous character.
      break;
    }
 }

 t.stop();
 duration = t.time();
 printf("\nYour typing speed is :");
 printf("\n%6.2f  characters per minute",60*letter_count/duration);
 printf("\n%6.2f  words per minute (Actual)",60*space_count/duration);
 printf("\n%6.2f  words per minute (Average)",60*letter_count/duration/5);

 getch();
}