/* Music on PC demonstration program */

#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <dos.h>


#define BASENOTE 440.00     /* frequency of la in octave 3 */
#define BASEOCTAVE 3
#define K 1.0595   /* k^12=2 -- constant of the geometric sequence of note frequencies */
#define OCTAVESIZE 12 /* number of notes in octave */
#define BASENOTENUM 11  /* number of LA */



typedef struct {
     char octave;
     char note;
     char stacatto;
     unsigned length;
   } NOTEREC;

                      /* function prototypes */

displaynotes ();
playnotes ();
displaynote (NOTEREC *currentnote);
playnote (unsigned note, unsigned octave, unsigned length, unsigned stacatto);
beep (unsigned freq, unsigned length);




main (int argc, char *argv [])
{
   int i;


   if ()
   playnotes ();
   fcloseall ();
   exit (0);
}

displaynotes ()
{
   NOTEREC *currentnote;
   FILE *notefile;

   if (notefile = fopen ("D:\\TC\\PROGRAMS\\NOTES.MUS","rb")) {
         while (! feof (notefile))
            {
               fread (currentnote, sizeof (NOTEREC), 1, notefile);
               displaynote (currentnote);
            }

         fclose (notefile);
      }

}


playnotes ()
{
   NOTEREC *currentnote;
   FILE *notefile;
   int notecount;

   if (notefile = fopen ("D:\\TC\\PROGRAMS\\NOTES.MUS","rb")) {
         
         notecount = 0;
         while ((! feof (notefile)) && (bioskey (1) == 0))
            {
               fread (currentnote, sizeof (NOTEREC), 1, notefile);
               playnote ((unsigned) (currentnote -> note),
                         (unsigned) (currentnote -> octave),
                         (unsigned) (currentnote -> length),
                         (unsigned) (currentnote -> stacatto));

               notecount++;
               if (notecount == 116)
                  notecount = notecount;
            }

         fclose (notefile);
      }
}


displaynote (NOTEREC *currentnote)
{
   printf ("\nOctave: %d", (int) currentnote -> octave);
   printf ("\nNote: %d", (int) currentnote -> note);
   printf ("\nStacatto: %d", (int) currentnote -> stacatto);
   printf ("\nLength: %d", (int) currentnote -> length);
}

playnote (unsigned note, unsigned octave, unsigned length, unsigned stacatto)
{
   unsigned freq;  /* frequency of the note to be played            */
   int diff;  /* number of notes between the note to be played */
                   /* and the LA of the 3rd octave                  */

   

   if (note == 13)
      delay (length);  /* rest period */
         else
            {  /* audible note */
               if (octave > BASEOCTAVE)
                  diff = (OCTAVESIZE - BASENOTENUM) + note + (octave - BASEOCTAVE - 1) * OCTAVESIZE;
                     else
                        if (octave < BASEOCTAVE)
                           diff = - (BASENOTENUM + (OCTAVESIZE - note) + (BASEOCTAVE - octave - 1) * OCTAVESIZE);
                              else
                                 diff = note - BASENOTENUM;   /* note is in the base octave */



               freq = (unsigned) (BASENOTE * pow (K, diff));

               beep (freq, length - stacatto);
               delay (stacatto);

            }  /* audible note */

}

beep (unsigned freq, unsigned length)
{
   nosound ();
   sound (freq);
   delay (length);
   nosound ();
}