Basic Game Logic - 3D Game Development Practical Introduction - page 137

floatdistance=
Vector3.Distance(
transform.position,
t.transform.position);
//Distance between projectile
//and nearest target
floatminDistance=
Vector3.Distance(
transform.position,
nearest.transform.position);
//Update the nearest target if necessary if(distance <
minDistance){
nearest = t;
}