/*----------------------------------------------------------------------
     Sphere                                   Susan L. Weller           
  ----------------------------------------------------------------------
         This program will generate a given number of points that lie
    on the unit sphere. The number of points is given on  the command line.
  ---------------------------------------------------------------------- */
#include <stdio.h>
#include <math.h>

#define MAX_INT    	2147483647     /* Max int is 2^31 - 1 */
#define FUZZ 		0.000001

main( argc, argv )
int argc;
char *argv[];
{
int n;
double x, y, z, r;

	srandom( (int) time((long *) 0 ) );
	if ( argc != 2 )
   	printf( "Usage: sphere <number of random points> \n" ),
   	exit(1);

	n = atoi( argv[1] );            /* n is number of points */

	while (n--) {
    	      do {
            	    /* the do-while will generate points until one
               	       is inside the unit sphere.               */
	    	    x = 2.0 * (double) random() / MAX_INT  - 1.0;
	    	    y = 2.0 * (double) random() / MAX_INT  - 1.0;
	    	    z = 2.0 * (double) random() / MAX_INT  - 1.0;
	    	    r = sqrt( x*x + y*y + z*z );
	      
    	      } while ( r <= FUZZ || r > 1.);
    	      printf ("%6d  %6d  %6d\n", (int) (100 * x/r), 
				      (int) (100 * y/r), (int) (100 * z/r) );
    	}
}