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

#include "point.h"


/* --------------------------------------------------------------------- */


point * Create_point () 
{
  point * ptr ;
  ptr = (point *) calloc( 1 , sizeof(point) ) ;
  return ptr ;
}


/* --------------------------------------------------------------------- */


void Destroy_point (point * ptr)
{
  free(ptr) ;
}


/* --------------------------------------------------------------------- */


void Load_point ( point * pt , float x , float y , float z )
{
  pt->x = x ;
  pt->y = y ;
  pt->z = z ;
}


/* --------------------------------------------------------------------- */


void Print_point ( point pt , FILE * stream )
{
  char message[100] ;
  char format[] = "x=%7.3f  y=%7.3f  z=%7.3f\n" ;
  sprintf ( message , format , pt.x , pt.y , pt.z ) ;
  if ( stream ) fprintf(stream,message) ; else printf(message) ;
}


/* --------------------------------------------------------------------- */


float radius ( point pt ) 
{
  return (float) sqrt( (double)(pt.x*pt.x) + (double)(pt.y*pt.y) + (double)(pt.z*pt.z) ) ;
}


/* --------------------------------------------------------------------- */


point sum ( point p1 , point p2 ) 
{
  point p ;
  p.x = p1.x + p2.x ;
  p.y = p1.y + p2.y ;
  p.z = p1.z + p2.z ;
  return p ;
}


/* --------------------------------------------------------------------- */


point diff ( point p1 , point p2 ) 
{
  point p ;
  p.x = p1.x - p2.x ;
  p.y = p1.y - p2.y ;
  p.z = p1.z - p2.z ;
  return p ;
}


/* --------------------------------------------------------------------- */


point scale ( point p1 , float d ) 
{
  point p ;
  p.x = p1.x * d ;
  p.y = p1.y * d ;
  p.z = p1.z * d ;
  return p ;
}


/* --------------------------------------------------------------------- */


float dist ( point p1 , point p2 )
{
  return radius ( diff ( p1 , p2 ) ) ;
}