You could do the distance calculation while scanning through the baddies:
PHP Code:
temp.close = -1; //index of closest baddy
temp.smallestdist = 9999; //distance from closest baddy
for (temp.i = 0; temp.i < compuscount; temp.i++) {
temp.dist = ((compus[temp.i].x - x)^2 + (compus[temp.i].y - y)^2) ^ 0.5;
if (temp.dist < temp.smallestdist) {
//This baddy is the closest, so update
temp.smallestdist = temp.dist;
temp.close = temp.i;
}
}