/*
 * Speed Fraction
 * by: Charlton Harrison
 * Computes the best approximate fractions for a decimal
 */

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <sys/types.h>

/* for kbhit() */
#include <sys/time.h>
#include <unistd.h>

/* Function for kbhit() - the gcc way */
/* Only works for the <return> key though... */
int kbhit()
{
    struct timeval wait;
    int ret;
    fd_set readfd;

    FD_ZERO(&readfd);
    FD_SET(0, &readfd);
    wait.tv_sec  = 0;   /* Wait zero seconds */
    wait.tv_usec = 0;
				    
    ret = select(1, &readfd, NULL, NULL, &wait);
    return(ret);
}


void main(int argc, char *argv[])
{
    int kcount=0;
    double x, h, m=0.5, lastp=0.0, p=0.0;
    long last10, lpa=0, lasta=0, a=0, lastb=0, b=0, e, t=0, c=1;


    /* Initializations */
    if (argc != 2) {
	printf("Usage: spfrcn [decimal]\n");
	exit(1);
    }
    printf("\nHit return at any time to stop...\n");
    x = atof(argv[1]);
    printf("Ok: %.16f\n", x);

    while (1) {						/* Main Loop */

	t++;  m+=x;  e=m;
	h=((double)e / (double)t);
	if (fabs(h-x) < fabs(p-x)) {
	    p=h;  a=e;  b=t;
	}

	if (a != lpa) {
	    if (h==x) {
		printf("%ld / %ld  :  %.16f\n", a, b, p);
		exit(1);
	    }
	    last10 = pow(10, ((int)log10(e)));
	    if ((int)(e/last10) != (int)(a/last10)) {
		printf("%ld / %ld  :  %.16f\n", a, b, p);
		lpa=a;
	    }
	}

	kcount++;
	if (kcount==1000) {     /* every 1000 loops check to see if kbhit */
	    kcount=0;
	    if (kbhit()) {
		exit(1);
	    }
	}

    }						/* End of Main Loop */

}