# 2.11BSD/src/games/trek/compkl.c

Compare this file to the similar file:
Show the results in this format:

```/*
* Copyright (c) 1980 Regents of the University of California.
* specifies the terms and conditions for redistribution.
*/

#ifndef lint
static char sccsid[] = "@(#)compkl.c	5.1 (Berkeley) 5/30/85";
#endif not lint

# include	"trek.h"

/*
**  compute klingon distances
**
**	The klingon list has the distances for all klingons recomputed
**	and sorted.  The parameter is a Boolean flag which is set if
**	we have just entered a new quadrant.
**
**	This routine is used every time the Enterprise or the Klingons
**	move.
*/

compkldist(f)
int	f;		/* set if new quadrant */
{
register int		i, dx, dy;
double			d;
double			temp;

if (Etc.nkling == 0)
return;
for (i = 0; i < Etc.nkling; i++)
{
/* compute distance to the Klingon */
dx = Ship.sectx - Etc.klingon[i].x;
dy = Ship.secty - Etc.klingon[i].y;
d = dx * dx + dy * dy;
d = sqrt(d);

/* compute average of new and old distances to Klingon */
if (!f)
{
temp = Etc.klingon[i].dist;
Etc.klingon[i].avgdist = 0.5 * (temp + d);
}
else
{
/* new quadrant: average is current */
Etc.klingon[i].avgdist = d;
}
Etc.klingon[i].dist = d;
}

/* leave them sorted */
sortkl();
}

/*
**  sort klingons
**
**	bubble sort on ascending distance
*/

sortkl()
{
struct kling		t;
register int		f, i, m;

m = Etc.nkling - 1;
f = 1;
while (f)
{
f = 0;
for (i = 0; i < m; i++)
if (Etc.klingon[i].dist > Etc.klingon[i+1].dist)
{
bmove(&Etc.klingon[i], &t, sizeof t);
bmove(&Etc.klingon[i+1], &Etc.klingon[i], sizeof t);
bmove(&t, &Etc.klingon[i+1], sizeof t);
f = 1;
}
}
}
```