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

#define BASEFREQ 1024

typedef struct note NOTE;

struct note {
  double phi;
  int age;
  double freq;
  double fade;
  double fadefactor;
  } ;

static NOTE notes[4];

static int nint(double d)
{
 if (d < 0) return(d-.5); else return(d+.5);
}

static void write_sample(int s)
{
 if (s < -32767) s = -32767;
 if (s > 32767) s = 32767;
 putchar((s>>8)&0xff);
 putchar(s&0xff);
}

static void init_note(NOTE *n, int start, double freq, double fade)
{
 n->phi = 0;
 n->age = -start;
 n->freq = freq;
 n->fade = 1;
 n->fadefactor = pow(.5,fade/5000);
}

static double note_value(NOTE *n)
{
 n->age ++;
 n->phi += (n->freq*2*M_PI) / 8000;
 if (n->phi >= 2*M_PI) n->phi -= 2*M_PI;
 if (n->age < 0)
  { return(0);
  }
 else if (n->age < 200)
  { return(n->age*sin(n->phi)/200);
  }
 else
  { return(sin(n->phi)*(n->fade*=n->fadefactor));
  }
}

int main(void);
int main(void)
{
 int i;

 /* some kind of fanfare? */
 init_note(&notes[0],0,BASEFREQ,3);
 init_note(&notes[1],200,(3*BASEFREQ)/2,8);
 init_note(&notes[2],400,(5*BASEFREQ)/3,6);
 init_note(&notes[3],600,2*BASEFREQ,4);
 for (i=0;i<8000;i++)
  { write_sample(nint( ( note_value(&notes[0]) +
			 note_value(&notes[1]) +
			 note_value(&notes[2]) +
			 note_value(&notes[3]) ) * 3000 ));
  }
 exit(0);
}