How to implement object selection and sorting in Unity3D?

Question

C++ / C#

How to implement object selection and sorting in Unity3D?
I have a cannon on the stage, approaching it, at a certain distance it selects an object and shoots at it, after death it selects another one that is in its radius of action, the
objects are
spammed but only one, and after his death (going out of the action boundary) she chose another
one . distance If the target is within a radius We enter the target (targets) into an array How exactly is better Since I think that with triggers this is a disastrous business
Or maybe
not I don't know
Thank you

Answer 1

I think what you need habrahabr.ru/post/148410
There are answers to most of your questions, and the rest you can think of yourself